tag:theconversation.com,2011:/africa/topics/carbohydrates-925/articles
Carbohydrates – The Conversation
2024-03-11T13:10:39Z
tag:theconversation.com,2011:article/224305
2024-03-11T13:10:39Z
2024-03-11T13:10:39Z
Want to build muscle? Why carbs could be just as important as protein
<figure><img src="https://images.theconversation.com/files/580113/original/file-20240306-24-ezfwd5.jpg?ixlib=rb-1.1.0&rect=0%2C20%2C6987%2C4637&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Porridge was one of the carbs Mark Taylor, 2023's "Mr Universe", included in his diet.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-caucasian-man-eating-muesli-bowl-2221418437">Ripio/ Shutterstock</a></span></figcaption></figure><p>High-protein, low-carb diets have long been considered the gold standard method for gym-goers and bodybuilders aiming to gain muscle and lose fat. But one bodybuilding champion has shown that this might not necessarily be the only way of achieving a chiselled physique. </p>
<p>Mark Taylor, a 52-year-old bodybuilding veteran who in 2023 won the coveted “Mr Universe” title, <a href="https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-68308809">said in a recent interview</a> that the key to his success was actually embracing carbs. </p>
<p>For years, Taylor religiously stuck to a traditional <a href="https://www.healthline.com/nutrition/high-protein-low-carb-diet">high protein, low carb diet</a>, yet he felt tired all the time. It wasn’t until Taylor abandoned this thinking and his strict diet, to prioritise carbs and more calories, that he finally achieved his dream. </p>
<p>While this strategy might go against the norm, what does the science say? </p>
<h2>Building muscle with nutrition</h2>
<p>To shape up and gain muscle you <a href="https://pubmed.ncbi.nlm.nih.gov/9252485/">have to train</a> – there’s no getting around this. Muscle gains come from <a href="https://www.healthline.com/health/progressive-overload">progressive overload training</a>, which means either gradually increasing the weight you lift or performing more reps or sets of an exercise. </p>
<p>If the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6950543/">training is demanding</a> enough, <a href="https://pubmed.ncbi.nlm.nih.gov/11238774/">muscle adaptations</a> during the recovery period can lead to <a href="https://pubmed.ncbi.nlm.nih.gov/37382939/">improvements over time</a>.</p>
<p>More specifically, <a href="https://pubmed.ncbi.nlm.nih.gov/33487181/">muscle growth</a> is a balance between two processes: “<a href="https://pubmed.ncbi.nlm.nih.gov/34697259/">muscle protein synthesis</a>” (where new muscle tissue is made or repaired) and “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5790854/">muscle protein breakdown</a>” (where muscle tissue is degraded). Because these two processes are always occurring, the rate and balance between them, will affect overall gains. </p>
<p>Appropriate nutrition, alongside structured training, <a href="https://pubmed.ncbi.nlm.nih.gov/35389932/">supports these processes</a>. Proteins are essential as they contain amino acids (such as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848650/">leucine</a>) which provide the building blocks of muscle. </p>
<p>Evidence highlights that <a href="https://pubmed.ncbi.nlm.nih.gov/30255023/">daily protein intake</a> alongside <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6710320/">eating enough calories</a> may be most important for overall muscle gains. Other nutrients, such as essential <a href="https://pubmed.ncbi.nlm.nih.gov/21501117/">fats</a>, vitamins and minerals, are also relevant to the muscle building process. Conversely, <a href="https://pubmed.ncbi.nlm.nih.gov/31915482/">consuming fewer calories</a> than your body needs may negatively affect your training. </p>
<p>After training, it has also been shown that consuming <a href="https://pubmed.ncbi.nlm.nih.gov/19056590/">20g-40g</a> of “fast releasing” proteins (such as whey protein) may <a href="https://pubmed.ncbi.nlm.nih.gov/28642676/">accelerate muscle protein synthesis</a> in the short-term. Many gym goers also consume “slow releasing” proteins (such as casein protein) <a href="https://pubmed.ncbi.nlm.nih.gov/22330017/">before going to sleep</a> to reach daily protein needs or optimise recovery. </p>
<h2>So where do carbs fit in?</h2>
<p>While some studies show combining carbs and protein after exercise can lead to increased <a href="https://www.sciencedirect.com/science/article/pii/S0022316622097206">muscle protein synthesis</a>, other studies show that this is not the case when compared to consuming <a href="https://pubmed.ncbi.nlm.nih.gov/24149627/">protein alone</a>. This is because amino acids are key to this process, and carbs simply do not provide these building blocks so <a href="https://pubmed.ncbi.nlm.nih.gov/14594866/">cannot directly drive muscle protein synthesis</a>.</p>
<p>But carbs may have an influence on the degree of <a href="https://journals.physiology.org/doi/full/10.1152/japplphysiol.00333.2003">muscle protein breakdown</a> that happens. This is because carbs trigger the body to produce the hormone insulin, which has been shown to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2804964/">reduce protein breakdown</a>. </p>
<p>However, protein also influences insulin production, creating a similar effect. So if you have sufficient <a href="https://pubmed.ncbi.nlm.nih.gov/21131864/">protein post-exercise</a>, you could argue there’s no <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3850644/">need for additional carbs</a> from a muscle building perspective. So how do we explain Taylor’s success?</p>
<p>Many bodybuilders tend to go through a “bulking” phase, increasing the number of calories they eat daily by <a href="https://pubmed.ncbi.nlm.nih.gov/15107010/">around 15% or more</a> in an attempt to increase muscle mass. This is followed by a “cutting” phase to strategically reduce body fat in order to make muscles more visible. Using a low-carb approach can <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7911670/">promote fat loss</a>, resulting in a lean physique. This is why many gym enthusiasts and bodybuilders opt for this method. </p>
<figure class="align-center ">
<img alt="An assortment of carbs, including potatoes, pasta and porridge." src="https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=381&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=381&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=381&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=479&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=479&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580117/original/file-20240306-26-fhkipb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=479&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Carbs are important for energy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthy-food-best-sources-carbs-on-389062576">Tatjana Baibakova/ Shutterstock</a></span>
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<p>But low-carb diets also means less energy, which could lead to <a href="https://pubmed.ncbi.nlm.nih.gov/34205107/">weakened immunity, greater fatigue</a> and <a href="https://pubmed.ncbi.nlm.nih.gov/17617997/">reduced performance</a>. Low-carb diets can also disrupt <a href="https://journals.lww.com/nutritiontodayonline/abstract/2023/03000/low_energy_availability_in_athletes__understanding.4.aspx">menstrual function</a> in women, and <a href="https://pubmed.ncbi.nlm.nih.gov/21058750/">lower testosterone</a> (needed for muscle development) – particularly in men. So these popular “cutting” strategies could be detrimental for some people. </p>
<p>Carbohydrates supply us with energy in the form of glucose, which is then stored in the muscle as glycogen for later use. Training in the gym can be demanding, which means we use <a href="https://pubmed.ncbi.nlm.nih.gov/29444266">glycogen stores</a> to fuel us more rapidly. </p>
<p>This allows us to train more intensely, which indirectly influences muscle protein synthesis. If you don’t <a href="https://pubmed.ncbi.nlm.nih.gov/32826640/">refuel with carbs</a> and continue to train in a low-glycogen state, it may not only <a href="https://pubmed.ncbi.nlm.nih.gov/31100798/">affect the muscle-building process</a>, but overall training results. </p>
<p>Choice of carbs also makes a difference. In Taylor’s case, choosing sweet potatoes and porridge meant that his diet favoured a <a href="https://pubmed.ncbi.nlm.nih.gov/9108636/">lower glycaemic approach</a>. </p>
<p>The glycaemic index (GI) is a measure of how quickly the carbohydrates in a particular food increase blood sugar. Low GI foods (such as porridge) have a slower releasing effect. This not only <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5154680/">affects mood</a>, but also leads to sustained energy throughout the day – combating feelings of fatigue while benefiting <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2654909">other aspects of health</a> – such as <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/low-glycemic-index-diet/art-20048478">lowering blood pressure</a>.</p>
<p>But while low GI foods are beneficial over the course of the day, research shows that higher GI foods (such as white pasta, bagels or granola) after hard or prolonged training support <a href="https://pubmed.ncbi.nlm.nih.gov/8226443/">rapid recovery of glycogen</a>. So a combination of low GI and high GI foods throughout the day could be a useful training and recovery strategy.</p>
<p>Athlete or not, increasing muscle mass requires work and our diet can <a href="https://pubmed.ncbi.nlm.nih.gov/28698222/">influence this</a>. <a href="https://pubmed.ncbi.nlm.nih.gov/27023595/">Feeding our muscles</a> with protein, while <a href="https://pubmed.ncbi.nlm.nih.gov/29371857/">fuelling workouts</a> with carbs, may well offer a more effective way to achieve your goal. </p>
<p>If, like Taylor, you’re not seeing the results you want, perhaps carbs are the missing piece of the puzzle.</p><img src="https://counter.theconversation.com/content/224305/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Professor Justin Roberts works for Danone Nutricia Research and Anglia Ruskin University, and has previously received external research funding unrelated to this article.</span></em></p><p class="fine-print"><em><span>Henry Chung and Joseph Lillis do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Nutrition plays a very important role in the muscle building process.
Justin Roberts, Professor of Nutritional Physiology, Anglia Ruskin University
Henry Chung, Lecturer in Sport and Exercise Science, University of Essex
Joseph Lillis, PhD Candidate in Nutritional Physiology, Anglia Ruskin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/223731
2024-02-28T19:15:27Z
2024-02-28T19:15:27Z
‘Naked carbs’ and ‘net carbs’ – what are they and should you count them?
<figure><img src="https://images.theconversation.com/files/578191/original/file-20240227-30-zvycnf.jpg?ixlib=rb-1.1.0&rect=9%2C18%2C6097%2C4001&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/tasty-soft-buns-in-wicker-basket-4197986/">Pexels/Karolina Grabowska</a></span></figcaption></figure><p>According to <a href="https://www.tiktok.com/channel/carbs?lang=en">social media</a>, carbs come in various guises: naked carbs, net carbs, complex carbs and more. </p>
<p>You might be wondering what these terms mean or if all carbs are really the same. If you are into “carb counting” or “cutting carbs”, it’s important to make informed decisions about what you eat. </p>
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Read more:
<a href="https://theconversation.com/stop-hating-on-pasta-it-actually-has-a-healthy-ratio-of-carbs-protein-and-fat-197416">Stop hating on pasta – it actually has a healthy ratio of carbs, protein and fat</a>
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<h2>What are carbs?</h2>
<p>Carbohydrates, or “carbs” for short, are one of the main sources of <a href="https://www.tandfonline.com/doi/full/10.1080/10408398.2017.1392287">energy</a> we need for brain function, muscle movement, digestion and pretty much everything our bodies do. </p>
<p>There are two classifications of carbs, <a href="https://www.ncbi.nlm.nih.gov/books/NBK459280/">simple and complex</a>. Simple carbs have one or two sugar molecules, while complex carbs are three or more sugar molecules joined together. For example, table sugar is a simple carb, but starch in potatoes is a complex carb. </p>
<p>All carbs need to be broken down into individual molecules by our digestive enzymes to be absorbed. Digestion of complex carbs is a much slower process than simple carbs, leading to a more gradual blood sugar increase. </p>
<p>Fibre is also considered a complex carb, but it has a structure our body is not capable of digesting. This means we don’t absorb it, but it helps with the movement of our <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-3010.2007.00616.x">stool and prevents constipation</a>. Our good gut bacteria also love fibre as they can digest it and use it for energy – important for a healthy gut. </p>
<h2>What about ‘naked carbs’?</h2>
<p>“Naked carbs” is a popular term usually used to refer to foods that are mostly simple carbs, without fibre or accompanying protein or fat. White bread, sugary drinks, jams, sweets, white rice, white flour, crackers and fruit juice are examples of these foods. Ultra-processed foods, where the grains are stripped of their outer layers (including fibre and most nutrients) leaving “refined carbs”, also fall into this category.</p>
<p>One of the problems with naked carbs or refined carbs is they <a href="https://link.springer.com/article/10.1007/s11033-020-05611-3">digest and absorb quickly</a>, causing an immediate rise in blood sugar. This is followed by a rapid spike in <a href="https://diabetesjournals.org/diabetes/article/25/9/741/4132/Plasma-Glucose-and-Insulin-Responses-to-Orally">insulin</a> (a hormone that signals cells to remove sugar from blood) and then a drop in blood sugar. This can lead to hunger and cravings – a vicious cycle that only gets worse with eating more of the same foods. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-want-to-eat-healthily-so-why-do-i-crave-sugar-salt-and-carbs-212114">I want to eat healthily. So why do I crave sugar, salt and carbs?</a>
</strong>
</em>
</p>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="donut with sprinkles in close up" src="https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578193/original/file-20240227-24-ibtpni.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Naked carbs can make blood sugars spike then crash.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/pink-doughnut-with-colorful-sprinkles-intilt-shift-lens-3784440/">Pexels/Alexander Grey</a></span>
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<h2>What about ‘net carbs’?</h2>
<p>This is another popular term tossed around in dieting discussions. Net carbs refer to the part of the carb food that we actually absorb. </p>
<p>Again, fibre is not easily digestible. And some carb-rich foods contain sugar alcohols, such as sweeteners (like xylitol and sorbitol) that have limited absorption and little to no effect on blood sugar. Deducting the value of fibre and sugar alcohols from the total carbohydrate content of a food gives what’s considered its net carb value. </p>
<p>For example, canned pear in juice has around <a href="https://afcd.foodstandards.gov.au/fooddetails.aspx?PFKID=F006593">12.3g of “total carbohydrates” per 100g</a>, including 1.7g carb + 1.7g fibre + 1.9g sugar alcohol. So its net carb is 12.3g – 1.7g – 1.9g = 8.7g. This means 8.7g of the 12.3g total carbs impacts blood sugar.</p>
<p>The nutrition labels on packaged foods in Australia and New Zealand usually list fibre separately to carbohydrates, so the net carbs have already been calculated. This is not the case in other countries, where “total carbohydrates” are listed.</p>
<p><div data-react-class="TiktokEmbed" data-react-props="{"url":"https://www.tiktok.com/@andydoeshealthy/video/7040499646451502342"}"></div></p>
<h2>Does it matter though?</h2>
<p>Whether or not you should care about net or naked carbs depends on your dietary preferences, health goals, food accessibility and overall nutritional needs. Generally speaking, we should try to limit our consumption of simple and refined carbs. </p>
<p>The latest <a href="https://iris.who.int/bitstream/handle/10665/370420/9789240073593-eng.pdf?sequence=1">World Health Organization guidelines</a> recommend our carbohydrate intake should ideally come primarily from whole grains, vegetables, fruits and pulses, which are rich in complex carbs and fibre. This can have significant health benefits (to <a href="https://pubmed.ncbi.nlm.nih.gov/33096647/">regulate hunger, improve cholesterol or help with weight management</a>) and reduce the risk of conditions <a href="https://pubmed.ncbi.nlm.nih.gov/33096647/">such as heart disease, obesity and colon cancer</a>.</p>
<p>In moderation, naked carbs aren’t necessarily bad. But pairing them with fats, protein or fibre <a href="https://www.thelancet.com/article/S0140-6736(18)31809-9/fulltext">can slow down the digestion</a> and absorption of sugar. This can help to stabilise blood sugar levels, prevent spikes and crashes and <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-3010.2007.00616.x">support personal weight management goals</a>. If you’re managing diabetes or insulin resistance, paying attention to the composition of your meals, and the quality of your carbohydrate sources is essential.</p>
<p>A <a href="https://theconversation.com/what-are-ketogenic-diets-can-they-treat-epilepsy-and-brain-cancer-83401">ketogenic (high fat, low carb) diet</a> typically restricts carb intake to between 20 and 50g each day. But this carb amount refers to net carbs – so it is possible to eat more carbs from high-fibre sources.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="salad with quinoa and vegetables" src="https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578196/original/file-20240227-24-vpjsg8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Choose complex carbohydrates with lots of fibre.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthy-salad-spinachquinoa-roasted-vegetables-201536141">Shutterstock</a></span>
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<p>
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Read more:
<a href="https://theconversation.com/how-much-protein-do-i-need-as-i-get-older-and-do-i-need-supplements-to-get-enough-215695">How much protein do I need as I get older? And do I need supplements to get enough?</a>
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</em>
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<h2>Some tips to try</h2>
<p>Some simple strategies can help you get the most out of your carb intake:</p>
<ul>
<li><p>reduce your intake of naked carbs and foods high in sugar and white flour, such as white bread, table sugar, honey, lollies, maple syrup, jam, and fruit juice</p></li>
<li><p>opt for protein- and fibre-rich carbs. These include oats, sweet potatoes, nuts, avocados, beans, whole grains and broccoli</p></li>
<li><p>if you are eating naked carbs, dress them up with some protein, fat and fibre. For example, top white bread with a nut butter rather than jam </p></li>
<li><p>if you are trying to reduce the carb content in your diet, be wary of any <a href="https://link.springer.com/article/10.1007/s12603-020-1417-1">symptoms of low blood glucose</a>, including headaches, nausea, and dizziness </p></li>
<li><p>working with a health-care professional such as an accredited practising dietitian or your GP can help develop an individualised diet plan that meets your specific needs and goals.</p></li>
</ul>
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<p><em>Correction: this article has been updated to indicate how carbohydrates are listed on food nutrition labels in Australia and New Zealand.</em></p><img src="https://counter.theconversation.com/content/223731/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
All carbs need to be broken down by our digestive enzymes to be absorbed. Digestion of complex carbs is a much slower process than simple carbs, leading to a more gradual blood sugar increase.
Saman Khalesi, Senior Lecturer and Discipline Lead in Nutrition, School of Health, Medical and Applied Sciences, CQUniversity Australia
Anna Balzer, Lecturer, Medical Science School of Health, Medical and Applied Sciences, CQUniversity Australia
Charlotte Gupta, Postdoctoral research fellow, CQUniversity Australia
Chris Irwin, Senior Lecturer in Nutrition and Dietetics, School of Health Sciences & Social Work, Griffith University
Grace Vincent, Senior Lecturer, Appleton Institute, CQUniversity Australia
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/217622
2023-11-17T13:29:07Z
2023-11-17T13:29:07Z
Thanksgiving sides are delicious and can be nutritious − here’s the biochemistry of how to maximize the benefits
<figure><img src="https://images.theconversation.com/files/560008/original/file-20231116-25-qa3919.jpg?ixlib=rb-1.1.0&rect=371%2C19%2C1212%2C1371&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Side dishes made with colorful vegetables are a holiday staple for many. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/thanksgiving-table-with-turkey-and-sides-royalty-free-image/1036967058?phrase=thanksgiving+vegetables&adppopup=true">VeselovaElena/iStock via Getty Images</a></span></figcaption></figure><p>While people usually think first about the turkey or the ham during holiday meals, the sides are what help balance your plate. Colorful vegetables like green beans, collard greens, roasted carrots and mashed sweet potatoes are loaded with important micronutrients. But how you prepare them will help determine whether you get the most nutritional value out of each bite this holiday season.</p>
<p>As <a href="https://blog.richmond.edu/pollocklab/">a biochemist</a>, I know that food is made up of many chemical substances that are crucial for human growth and function. These chemical substances are called nutrients and can be divided into macronutrients, such as carbohydrates, fats and proteins, and micronutrients, such as vitamins and minerals.</p>
<p>Vegetables are <a href="https://www.cdc.gov/nutrition/micronutrient-malnutrition/micronutrients/index.html">full of micronutrients</a> that human bodies need for metabolism – or converting food into energy – as well as to form and maintain cells and tissues. These micronutrients can be classified into three types: minerals, water-soluble vitamins and fat-soluble vitamins.</p>
<h2>Minerals</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Alt text" src="https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=135&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=135&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=135&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=169&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=169&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559444/original/file-20231114-25-uczoq8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=169&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The dietary minerals found in vegetables.</span>
<span class="attribution"><span class="source">Julie Pollock</span></span>
</figcaption>
</figure>
<p>The greens – collard greens, kale, spinach, green beans – on your table are rich sources of the elements <a href="https://ods.od.nih.gov/factsheets/Magnesium-Consumer/">magnesium</a> and <a href="https://ods.od.nih.gov/factsheets/Calcium-Consumer/">calcium</a>. Your body needs these two major minerals for muscle movement and bone health. </p>
<p>Magnesium is essential for many of the enzymes that play important roles in DNA synthesis and repair, as well as protein production and metabolic function. The cellular processes, especially <a href="https://www.sciencedirect.com/topics/neuroscience/dna-synthesis">accurate DNA synthesis</a>, are important in protecting your body from developing diseases such as cancer. Calcium helps regulate <a href="https://www.news-medical.net/health/pH-in-the-Human-Body.aspx">the pH in your body</a>, influences your metabolism and strengthens your nerve impulses. Nerve impulses are important for your senses and your memory. </p>
<p>Greens are also <a href="https://ods.od.nih.gov/factsheets/Iron-Consumer/">a source of iron</a> – you were right, Popeye! – which is particularly important for the oxygen-binding proteins hemoglobin and myoglobin that transfer and store oxygen in your body, respectively. In addition, human bodies require iron for processes that help generate energy, protect against oxidative damage and make hormones.</p>
<p>Orange vegetables – carrots, pumpkin, sweet potatoes and squash – contain some levels of calcium and iron as well as <a href="https://doi.org/10.3945/an.112.003533">high levels of potassium</a>. Potassium is important for muscle movement, nerve impulses and maintaining low blood pressure. Although not a colorful vegetable, white potatoes also contain very <a href="https://doi.org/10.3945/an.112.003533">high levels of potassium</a>. </p>
<h2>Water-soluble vitamins</h2>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two diagrams showing Vitamin B6, a hexagon with three branches with 'OH' attached, and vitamin C, a hexagon with two Os and four branches with OH coming off." src="https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=320&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=320&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559445/original/file-20231114-15-is56e7.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=320&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The structures of water-soluble vitamins found in vegetables.</span>
<span class="attribution"><span class="source">Julie Pollock</span></span>
</figcaption>
</figure>
<p>Most green and orange vegetables contain <a href="https://doi.org/10.1146/annurev.nu.14.070194.002103">high levels of vitamin C</a>. Vitamin C is an important water-soluble vitamin because it acts as an antioxidant. <a href="https://theconversation.com/13-ways-to-get-more-antioxidants-and-why-you-need-to-70035">Antioxidants protect your cells</a> against certain types of damage caused by very reactive molecules known as free radicals. </p>
<p>In addition, vitamin C can enhance immune response and is essential for the <a href="https://www.healthline.com/nutrition/collagen">synthesis of collagen</a> – the major protein in your skin. Although taking large levels of vitamin C will not <a href="https://www.ncbi.nlm.nih.gov/books/NBK279544/">keep you from ever getting sick</a>, a healthy amount can help your skin stay soft, help you avoid diseases like scurvy and potentially shorten the length of a cold.</p>
<p>The white potatoes on the table have high levels of <a href="https://doi.org/10.3390/nu13093229">vitamin B6</a>, which is a component of enzymes essential for carbohydrate, fat and protein metabolism. It also helps create healthy blood cells and is important in the production of neurotransmitters such as <a href="https://brain.harvard.edu/hbi_news/exploring-how-serotonin-and-dopamine-interact/">serotonin and dopamine</a>, which both regulate pleasure and happiness.</p>
<h2>Fat-soluble vitamins</h2>
<figure class="align-center ">
<img alt="Two diagrams, the left showing the chemical structure of Vitamin K, the right showing the chemical structure of Vitamin A" src="https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=151&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=151&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=151&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=190&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=190&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559446/original/file-20231114-29-d1rqea.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=190&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The structures of fat-soluble vitamins found in vegetables.</span>
<span class="attribution"><span class="source">Julie Pollock</span></span>
</figcaption>
</figure>
<p>One of the most important vitamins you get from the green vegetables, especially leafy ones like kale, spinach, collards and Brussels sprouts, is <a href="https://ods.od.nih.gov/factsheets/VitaminK-Consumer/">vitamin K</a>. Vitamin K is an essential component of enzymes that make proteins in bone and proteins that help clot blood after injuries. </p>
<p><a href="https://ods.od.nih.gov/factsheets/VitaminA-Consumer/">Vitamin A</a> is another important fat-soluble vitamin found in spinach and orange vegetables. The source of vitamin A in vegetables is actually <a href="https://www.healthline.com/health/beta-carotene-benefits">beta carotene</a>, which gets broken into two molecules of active vitamin A after consumption. Vitamin A is essential to vision as well as cell differentiation, reproduction, bone health and immune system function. </p>
<h2>Absorption of micronutrients</h2>
<p>Consuming vegetables that contain micronutrients is very important, but just as important is your body’s ability to absorb the nutrients and transport them to the cells that need them. Macronutrients like carbohydrates, fats and proteins that primarily make up the food we eat are very efficiently absorbed into your bloodstream. </p>
<p>However, only 3%-10% of some micronutrients <a href="https://www.pearson.com/en-us/subject-catalog/p/science-of-nutrition-the/P200000007016/9780135371565">actually get distributed throughout your body</a>. Other ingredients and factors in your food can moderate whether you absorb vitamins and minerals.</p>
<p>Therefore, it is important to prepare vegetables in a way that can enhance the body’s ability to absorb their essential vitamins and minerals.</p>
<p>One good example of this is iron – specifically, the <a href="https://doi.org/10.3390/nu11051049">iron in the food you consume</a>. Heme iron, which is the form necessary for incorporation into your body, comes only from animal products and is the most easily absorbed. </p>
<p>The plant-based iron contained in green and orange vegetables, on the other hand, is not bound to a heme, and your body can’t absorb it as readily. Consuming vitamin C alongside vegetables can <a href="https://doi.org/10.1111/j.1749-6632.1980.tb21325.x">increase the uptake of nonheme iron</a>. So, a squeeze of lemon or orange juice can not only enhance the flavor of your vegetables but the micronutrients you obtain from them.</p>
<p>Fat-soluble vitamins, like vitamin K and vitamin A, are best absorbed when the meal <a href="https://medlineplus.gov/ency/article/002399.htm">contains some dietary fat</a>, which you can get from oil. This is particularly important for vitamin K because green vegetables are its primary dietary source. This is in contrast to the other minerals and vitamins discussed that can also be obtained from animals or legumes that contain some amounts of dietary fat already.</p>
<p>After consumption, vitamin K must be packaged with other fats in <a href="https://doi.org/10.1093/nutrit/nuab061">structures called micelles or lipoproteins</a> that can move around in the bloodstream. That means that it’s a good idea to prepare your greens with some source of fat – olive oil, avocado oil, butter or even a little bacon grease.</p>
<p>So, if you’re staring at the southern style collard greens on your plate and wondering whether they’re as healthy as eating a raw green leaf, think about it in terms of the biochemistry. While raw greens provide you with plenty of fiber and minerals, they won’t help your vitamin K levels as greens cooked in oil will. </p>
<p>Enjoy your time around the holiday table. Load up your plate with everything you like to eat, and make sure to not go completely fat-free in order to help your body process and use all the micronutrients.</p><img src="https://counter.theconversation.com/content/217622/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julie Pollock receives funding from the National Institutes of Health. </span></em></p>
The turkey doesn’t have to be the star this Thanksgiving. Vegetable side dishes are packed with nutrients − depending on how you prepare them, they can help keep you energized this holiday season.
Julie Pollock, Associate Professor of Chemistry, University of Richmond
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/214388
2023-10-24T19:18:09Z
2023-10-24T19:18:09Z
Brown, red, black, riceberry – what are these white rice alternatives, and are they actually healthier?
<figure><img src="https://images.theconversation.com/files/555154/original/file-20231023-25-6g0lg2.jpg?ixlib=rb-1.1.0&rect=66%2C225%2C5043%2C3076&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.pexels.com/photo/rice-in-white-ceramic-bowl-1306548/">Suzy Hazelwood/Pexels</a></span></figcaption></figure><p>Throughout history, rice has remained an important food staple. It supports the nutritional needs of more than <a href="https://education.nationalgeographic.org/resource/wbt-staple-food-crops-world/">half of the global population</a>. </p>
<p>While you might be familiar with a handful of types, there are <a href="https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-019-0017-3">more than 40,000 different varieties</a> of cultivated rice – a testament to the diversity and adaptability of this staple crop.</p>
<p>Rice, much like other grains, is the edible starchy kernel of a grass plant. In fact, the vast majority of rice varieties (although not all) belong to just one species – <em>Oryza sativa</em>.</p>
<p>If you have ever found yourself at the supermarket, overwhelmed by the number of rice options available, you are not alone. From aromatic Thai “jasmine” rice used in curries, to the “basmati” rice of India and the sticky “arborio” for making creamy Italian risotto, each variety, or cultivar, is distinguished by its grain length, shape and colour. </p>
<p>Each cultivar also has its own flavour, texture and unique nutrient properties. To make things more complicated, some varieties are higher in anthyocyanins – antioxidants that protect the body’s cells from damage. These rice varieties are known by their colour – for example, red or black rice.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a yellow-green plant cascading with elongated seeds" src="https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555155/original/file-20231023-21-rohqa5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><em>Oryza sativa</em> is a major food crop – a grass plant cultivated into thousands of varieties.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/paddy-oryza-sativa-major-crop-which-1829709263">Lakhan Rakshit/Shutterstock</a></span>
</figcaption>
</figure>
<h2>What is brown rice?</h2>
<p>Compared to white rice, brown rice is a whole grain with only the inedible outer hull removed. It is largely <a href="https://www.ers.usda.gov/topics/crops/rice/rice-sector-at-a-glance/">grown in</a> India, Pakistan and Thailand.</p>
<p>To make white rice, the bran (outer shell) of the grains is removed. In brown rice, the bran and germ (core of the grain) are still intact, giving this type of rice its tan colour and high fibre content. Brown rice naturally contains <a href="https://afcd.foodstandards.gov.au/fooddetails.aspx?PFKID=F007641">more nutrients</a> than white rice, including double the amount of dietary fibre and substantially higher magnesium, iron, zinc and B group vitamins, including folic acid.</p>
<p>Brown rice also contains polyphenols and flavonoids – types of antioxidants that protect the body from stress.</p>
<p>It is often sold as a longer grain option and has a similar nutty flavour to black and red rice cultivars, though some chefs suggest the texture is slightly chewier. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dark bowl with clumpy tan coloured rice being picked up with wooden chopsticks" src="https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555157/original/file-20231023-17-9f64xh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Brown rice owes its colour and texture to the fact it contains bran – the fibrous outer layer of the grain.</span>
<span class="attribution"><span class="source">pro ust/Shutterstock</span></span>
</figcaption>
</figure>
<h2>Fancy black rice</h2>
<p>While not as common as other varieties, black rice – also called purple rice due to its colouring – is high in anthocyanins. In fact, black rice <a href="https://pubs.acs.org/doi/epdf/10.1021/jf0606609">contains the same antioxidant</a> type that gives “superfoods” like <a href="https://doi.org/10.1016/j.jfca.2022.104697">blueberries and blackberries</a> their deep purple colour.</p>
<p>The <em>Oryza sativa</em> variant of <a href="https://www.sciencedirect.com/science/article/pii/S0308814619314165">black rice</a> is grown primarily in Asia and exported globally, while the <em>Oryza glaberrima</em> variant is native to and grown only in Africa. Among black rices there are also different shades, from japonica black rice, Chinese black rice, Thai black rice through to Indonesian black rice. </p>
<p>With its antioxidant properties, some would argue black rice is one of the healthiest choices due to its protective effects for <a href="https://link.springer.com/article/10.1007/s13668-023-00496-7">heart health and metabolic diseases</a>.</p>
<p>Black rice can be a short, medium or long grain and has only the outermost layer (inedible hull) removed for consumption. The bran and germ remain intact, similar to brown rice, making it a high fibre food. Black rice has been described by some foodies to have a mild nutty and even slightly sweet flavour. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a salad on a dark plate with chickpeas, tomato slices and purple rice in the foreground" src="https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555193/original/file-20231023-17-f2431i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Black rice is also known as purple rice due to its colour when cooked.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthy-black-rice-salad-turmeric-chickpea-1679613025">Alp Aksoy/Shutterstock</a></span>
</figcaption>
</figure>
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</em>
</p>
<hr>
<h2>Iron-rich red rice</h2>
<p>Similar to black rice, red rice, or <em>Oryza rufipogon</em>, is a medium or long grain variety coloured by its anthocyanin content. Interestingly, it is considered an <a href="https://weeds.org.au/profiles/red-rice-wild-rice/">edible weed</a> growing alongside other rice varieties and primarily grown in Asia as well as Northern Australia. </p>
<p>The difference in colour compared to black rice types is due to the <a href="https://www.sciencedirect.com/science/article/pii/S0963996922007840">amount and type</a> of anthyocyanins (specifically catechins and epicatechins) in red rice. </p>
<p><a href="https://journalofethnicfoods.biomedcentral.com/articles/10.1186/s42779-019-0017-3">Red rice</a> also contains more iron and zinc compared to white, black or brown varieties. The anthocyanins found in red rice are used as a <a href="https://pubs.acs.org/doi/epdf/10.1021/jf0606609">pigment for colouring other foods</a> such as liquor, bread and ice cream.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A person rinsing orange coloured rice grains in an aluminium rice cooker pot" src="https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/555195/original/file-20231023-27-hxhj22.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Red rice has different types of antioxidants in it, giving the grains their russet red colour.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/washing-preparing-black-rice-healthy-concept-1203144292">sungong/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Is riceberry a type of rice, too?</h2>
<p>Despite the slightly confusing name, riceberry rice was originally developed in Thailand as a cross between a local jasmine rice and local purple rice variety, creating a lighter, <a href="https://www.openaccessgovernment.org/riceberry-rice-for-well-being/119541/">purple-coloured grain</a>. </p>
<p>Increasingly available in Asian grocers across Australia, this type of rice has a more favourable nutrient profile than brown rice and has a shorter cooking time similar to that of white jasmine rice. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/four-simple-food-choices-that-help-you-lose-weight-and-stay-healthy-112054">Four simple food choices that help you lose weight and stay healthy</a>
</strong>
</em>
</p>
<hr>
<h2>Rice is not just another carb</h2>
<p>Rice has many nutritional benefits besides providing the body with carbohydrates – its primary fuel source. Rice contains more than 15 essential vitamins and minerals including folic acid, magnesium, iron and zinc and is naturally gluten free, making it an appropriate substitute for people living with coeliac disease.</p>
<p>Brown, red and black rices are also whole grains, recommended as part of a healthy eating pattern. </p>
<p>In addition, different cultivars of rice have a low glycaemic index or GI – a measure of the speed at which carbohydrates raise blood sugar levels.</p>
<p>Generally speaking, the more colourful the rice variety, the lower its GI. This is a particularly important consideration for people living with diabetes. </p>
<p>Less frequently consumed rice varieties have nutritional benefits, including their anthocyanin and fibre content. However, they can be harder to find and are often pricier than more common white and brown varieties. </p>
<p>If you enjoy trying foods with unique flavours, try experimenting with black or red rice varieties. Whatever the colour, all types of rice have a place in a balanced diet.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/do-you-need-to-wash-rice-before-cooking-heres-the-science-204692">Do you need to wash rice before cooking? Here's the science</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/214388/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yasmine Probst receives funding from Multiple Sclerosis Australia and has previously received funding from various industry groups that are not affiliated with the topic of this article. She is affiliated with the National Health and Medical Research Council, Multiple Sclerosis Plus and Multiple Sclerosis Limited. </span></em></p><p class="fine-print"><em><span>Karen Zoszak receives funding from the Australian Government Research Training Program. </span></em></p><p class="fine-print"><em><span>Olivia Wills receives funding from Multiple Sclerosis Australia.</span></em></p>
There are more than 40,000 varieties of cultivated rice. If you’ve ever wondered about the differences between all the colourful rices at the supermarket, here’s a rundown.
Yasmine Probst, Associate professor, University of Wollongong
Karen Zoszak, Accredited Practising Dietitian, PhD Candidate, University of Wollongong
Olivia Wills, Accredited Practising Dietitian, PhD candidate, University of Wollongong
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/210565
2023-08-24T20:20:43Z
2023-08-24T20:20:43Z
Why do I crave sugar and carbs when I’m sick?
<figure><img src="https://images.theconversation.com/files/544126/original/file-20230823-24-jor56l.jpg?ixlib=rb-1.1.0&rect=0%2C179%2C5991%2C3808&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/imAfCYq7KH0">Adrian Swancar/Unsplash</a></span></figcaption></figure><p>Your nose is running, your head hurts and you feel like you’re coming down with a cold. You’re settling in on the couch for a sick day. Then you reach for the snacks. </p>
<p>When you’re sick, your appetite often decreases. So why, at other times, do you crave sugary treats and carbohydrate-loaded comfort foods?</p>
<p>A food <a href="https://pubmed.ncbi.nlm.nih.gov/28375878/">craving</a> goes beyond a mere desire to eat, it encompasses a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7399671/#CR1">complex mix</a> of emotional, behavioural, cognitive and physiological processes. Whether it’s the need for a quick energy source or a temporary relief from discomfort, our bodies and minds work in tandem to drive our food preferences.</p>
<p>Here we’ll explore the science behind why our bodies crave sugar and carbs – especially when we’re sick.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/3-reasons-you-feel-hungrier-and-crave-comfort-foods-when-the-weather-turns-cold-202831">3 reasons you feel hungrier and crave comfort foods when the weather turns cold</a>
</strong>
</em>
</p>
<hr>
<h2>Fuelling the immune system</h2>
<p>When sickness strikes, our immune system springs into action, requiring additional energy to combat invaders. </p>
<p>This heightened activity often leads to an increase in our <a href="https://pubmed.ncbi.nlm.nih.gov/36505552/">metabolic rate</a>, energy demands and nutritional requirements. </p>
<p>Sugary treats and carbs are quick sources of energy, satisfying this increased demand. </p>
<figure class="align-center ">
<img alt="Person eats a biscuit" src="https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544124/original/file-20230823-5286-u508sw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sugary treats are a quick source of energy.</span>
<span class="attribution"><a class="source" href="https://www.pexels.com/photo/person-holding-biscuit-with-both-hands-1204222/">Cats coming/Pexels</a></span>
</figcaption>
</figure>
<p>But while a high sugar diet during times of illness may help meet increased metabolic demands, it could also exacerbate the immune and inflammatory response, potentially impeding recovery. </p>
<p>In the longer term, high-sugar diets promote chronic <a href="https://pubmed.ncbi.nlm.nih.gov/33339337/">inflammation</a>, <a href="https://www.science.org/doi/10.1126/scitranslmed.aay6218?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">alter gut microbiota</a> composition, and are associated with chronic disease. For a <a href="https://www.mdpi.com/2072-6643/12/4/1181">well-functioning immune system</a>, aim for a <a href="https://www.who.int/news-room/fact-sheets/detail/healthy-diet">balanced intake</a> of <a href="https://pubmed.ncbi.nlm.nih.gov/31267783/">fruits, vegetables</a>, fibre, protein, and low-glycaemic carbohydrates.</p>
<h2>The stress response</h2>
<p>Being sick is stressful for the body. Acute mild or intense stress, like we’d see if we’re sick, boosts the “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921333/">flight or fight</a>” hormones adrenaline and cortisol. This mobilises stored energy to meet increased demands, but it can also curb appetite. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/31125634/">Prolonged stress</a> can disrupt energy balance, and cause nutritional deficiencies and alterations in gut and brain functions. This can reduce a person’s threshold for craving sugar and salt, increasing their preferences towards energy-dense foods.</p>
<p>The stress hormone cortisol can also increase your <a href="https://pubmed.ncbi.nlm.nih.gov/24123563/">preference</a> for high-calorie, comfort foods, which can <a href="https://pubmed.ncbi.nlm.nih.gov/36615866/">temporarily alleviate stress</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-happens-in-our-body-when-we-encounter-and-fight-off-a-virus-like-the-flu-sars-cov-2-or-rsv-207023">What happens in our body when we encounter and fight off a virus like the flu, SARS-CoV-2 or RSV?</a>
</strong>
</em>
</p>
<hr>
<h2>The brain’s reward system</h2>
<p>Comfort foods trigger your brain’s reward system, releasing feel-good neurotransmitters like <a href="https://pubmed.ncbi.nlm.nih.gov/30595479/">dopamine</a> and serotonin. </p>
<p>But “<a href="https://pubmed.ncbi.nlm.nih.gov/30951762/">sugar rushes</a>” are often short-lived and can lead to decreased alertness and heightened fatigue within an hour of consumption. </p>
<p>The link between carbohydrates (which the body converts to sugar) and serotonin can be traced back to 1971 when <a href="https://www.science.org/doi/10.1126/science.174.4013.1023?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed">researchers</a> found elevated tryptophan levels (serotonin’s precursor) in rats’ plasma and brains after a carbohydrate-rich diet. </p>
<p>Subsequent studies in humans established connections between carbohydrates and mood, especially in relation to <a href="https://pubmed.ncbi.nlm.nih.gov/2903717/">obesity, depression and seasonal affective disorder</a>. Therapies enhancing serotonin have since been shown to <a href="https://pubmed.ncbi.nlm.nih.gov/2903717/">reduce carbohydrate intake</a>.</p>
<figure class="align-center ">
<img alt="McDonald's French fries" src="https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/544140/original/file-20230823-27-lqld1n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">There’s more to our cravings than just a desire to eat.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/MyuR5q3KDmw">Unsplash/Brett Jordan</a></span>
</figcaption>
</figure>
<p>Remarkably, around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8911970/pdf/molecules-27-01680.pdf">90% of serotonin</a> production occurs in the gut. The vast microbial population in our gut exerts a potent influence on <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106557/">immunity, metabolism</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8293578/pdf/40168_2021_Article_1093.pdf">appetite</a>. </p>
<p>Recent mouse studies have even identified specific microbes linked to <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(22)01750-X">sugar binges after antibiotic treatment</a>.</p>
<h2>Some people eat less when they’re sick</h2>
<p>Not everyone craves sugar and carbs when they are sick. Some people eat less for a few reasons:</p>
<ul>
<li><p>they have less of an appetite. While <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610818/pdf/JDR2017-4527980.pdf">ghrelin</a> (the “hunger” hormone) levels might initially rise, prolonged illness can suppress appetite due to nausea, fatigue and discomfort. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5921333/">Critically ill</a> patients have reduced food intake and are at risk of malnutrition</p></li>
<li><p><a href="https://pubmed.ncbi.nlm.nih.gov/30777142/">metabolic adaptation</a>. The body might slow specific metabolic processes to conserve energy, reducing overall calorie requirements</p></li>
<li><p>altered taste perception. <a href="https://pubmed.ncbi.nlm.nih.gov/32195512/#:%7E:text=The%20ability%20of%20an%20individual%20to%20perceive%20tastes,intake%2C%20playing%20an%20important%20role%20in%20promoting%20satiation%2Fsatiety.">Taste</a> is an important component that affects both appetite and energy intake. Alterations in taste and smell is a common symptom when we are sick and was common with <a href="https://doi.org/10.1101/2020.04.05.20048421">COVID</a></p></li>
<li><p>consuming fluids like water, tea or broths might be more appealing and manageable than solid foods. These fluids provide hydration but contribute minimally to calorie intake.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-to-eat-when-you-have-covid-and-why-reaching-for-the-chicken-soup-is-not-a-bad-idea-202338">What to eat when you have COVID – and why reaching for the chicken soup is not a bad idea</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/210565/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hayley O'Neill is a wellness coach for Hayley M O'Neill Enterprises.</span></em></p>
A quick energy source or a temporary relief from discomfort? Here’s what drives our food preferences when we’re sick.
Hayley O'Neill, Assistant Professor, Faculty of Health Sciences and Medicine, Bond University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/205159
2023-07-03T11:53:03Z
2023-07-03T11:53:03Z
Fiber is your body’s natural guide to weight management – rather than cutting carbs out of your diet, eat them in their original fiber packaging instead
<figure><img src="https://images.theconversation.com/files/529655/original/file-20230601-21-meilfi.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Whole foods like unprocessed fruits, vegetables and grains are typically high in fiber.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/pattern-of-variety-fresh-of-organic-fruits-and-royalty-free-image/1455279498">Tanja Ivanova/Moment via Getty Images</a></span></figcaption></figure><p>Fiber might just be the key to healthy weight management – and nature packages it in perfectly balanced ratios with carbs when you eat them as whole foods. Think unprocessed fruits, vegetables, whole grains, beans, nuts and seeds. Research suggests that carbohydrates are meant to come packaged in <a href="https://doi.org/10.1007/s00394-019-02165-4">nature-balanced ratios</a> of total carbohydrates to fiber. In fact, certain types of fiber affect how completely your body <a href="https://doi.org/10.1038/s41467-023-38778-x">absorbs carbohydrates</a> and <a href="https://doi.org/10.1016/j.bcdf.2017.07.005">tells your cells how to process them</a> once they are absorbed.</p>
<p>Fiber slows the absorption of sugar in your gut. It also orchestrates the fundamental biology that recent blockbuster weight loss drugs like <a href="https://theconversation.com/drugs-that-melt-away-pounds-still-present-more-questions-than-answers-but-ozempic-wegovy-and-mounjaro-could-be-key-tools-in-reducing-the-obesity-epidemic-205549">Wegovy and Ozempic</a> tap into, but in a natural way. Your microbiome <a href="https://doi.org/10.3389/fendo.2020.00025">transforms fiber into signals</a> that stimulate the gut hormones that are the natural forms of these drugs. These in turn regulate how rapidly your stomach empties, how tightly your <a href="https://doi.org/10.2337/ds16-0026">blood sugar levels</a> are controlled and even how hungry you feel. </p>
<p>It’s as if unprocessed carbohydrates naturally come wrapped and packaged with their own instruction manual for your body on how to digest them.</p>
<p>I am a <a href="https://gastro.uw.edu/faculty/christopher-j-damman-md-ma">physician scientist and gastroenterologist</a> who has spent over 20 years studying how <a href="https://gutbites.org/">food affects the gut microbiome</a> and metabolism. The research is clear – fiber is important not just for happy bowel movements, but also for your blood sugar, weight and overall health.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/wxzc_2c6GMg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Different types of carbs have different effects on the body.</span></figcaption>
</figure>
<h2>Carbohydrates without their wrappers</h2>
<p>Unfortunately, most Americans get the majority of their carbohydrates stripped of their natural fibers. Modern processed grains like white rice and white flour as well as many ultraprocessed foods like some sugary breakfast cereals, packaged snacks and juices have removed these fibers. They essentially come unwrapped and without instructions for the body on how much it should absorb and how it should process them. In fact, <a href="https://doi.org/10.1177%2F1559827615588079">only 5% of Americans</a> eat the recommended amount of carbohydrates with enough of their natural packaging intact. Guidelines recommend <a href="https://doi.org/10.1136%2Fbmj-2020-054370">at least 25 to 30 grams</a> of fiber a day from food.</p>
<p>It may not be surprising that lack of fiber <a href="https://doi.org/10.1371/journal.pmed.1003053">contributes to diabetes and obesity</a>. What is surprising is that the fiber gap also likely contributes to <a href="https://doi.org/10.1016/s2468-1253(19)30257-2">heart disease</a>, certain <a href="https://doi.org/10.1093/ajcn/nqaa161">types of cancer</a> and maybe even <a href="https://doi.org/10.3233/jad-215493">Alzheimer’s disease</a>.</p>
<p>One popular approach to mitigating some of the ill health effects of low fiber and high refined carbohydrates has been to <a href="https://doi.org/10.1016/j.jacl.2019.08.003">limit carbohydrate intake</a>. Such approaches include the low-carb, keto, paleo and Atkins diets. Each diet is a variation on a similar theme of limiting carbohydrates to varying amounts in different ways.</p>
<p>There is scientific backing to the benefits of some of these diets. Research shows that limiting carbohydrates <a href="https://doi.org/10.3389/fnut.2021.702802">induces ketosis</a>, a biological process that frees energy from fat reserves during starvation and prolonged exercise. Low-carbohydrate diets can also help people lose weight and <a href="https://doi.org/10.1038/s41392-021-00831-w">lead to improvements</a> in blood pressure and inflammation.</p>
<p>That said, some keto diets may have negative effects on <a href="https://doi.org/10.3390/genes10070534">gut health</a>. It is also unknown how they may affect <a href="https://doi.org/10.3390/nu14173499">heart health, some forms of cancer</a> and other conditions in the long term.</p>
<p>Even more confusing, research shows that people with diets high in plant-sourced carbohydrates, like the Mediterranean diet, tend to lead the <a href="https://doi.org/10.3390%2Fnu13082540">longest and healthiest lives</a>. How can this be reconciled with studies that suggest that low-carbohydrate diets can benefit metabolic health?</p>
<h2>Is a carb a carb?</h2>
<p>The answer may have to do with the <a href="https://doi.org/10.1093%2Fjn%2Fnxac039">types of carbohydrates</a> that studies are evaluating. Limiting simple sugars and refined carbohydrates may improve certain aspects of metabolic health, as these are some of the most easily digested and absorbed calories. But a more sustainable and comprehensive way of improving health may be <a href="https://doi.org/10.3390%2Fnu12103045">increasing the percentage</a> of unprocessed, more complex and slowly absorbed carbohydrates that come with their natural packages and instructions intact – those that have fiber. </p>
<p>These natural carbohydrates can be found in whole grains, beans, nuts, seeds, fruits and vegetables. They come in ratios of total carbohydrate to fiber that <a href="https://doi.org/10.1371%2Fjournal.pone.0231572">rarely exceed 10-to-1 and are often 5-to-1 or lower</a>. Eating mostly whole foods is a simple way to ensure you’re consuming quality carbohydrates with the right ratios.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person looking at vegetables in farmers market" src="https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529656/original/file-20230601-29-v2vms0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fruits and vegetables typically come in ideal total carbohydrate-to-fiber ratios.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/young-asian-woman-shopping-fruits-and-vegetables-in-royalty-free-image/1477272111">Oscar Wong/Moment via Getty Images</a></span>
</figcaption>
</figure>
<p>But who doesn’t like to have a big bowl of pasta or cake with ice cream on occasion? Focusing on packaged processed foods that maintain carb-to-fiber ratios of at least as low as 10-to-1 or ideally 5-to-1 can help you make the best choices when picking more processed foods at the store. Take a look at the nutrition facts label and simply divide total carbohydrates by dietary fiber.</p>
<p>On occasions when you’re eating out or celebrating someone’s birthday, consider taking a fiber supplement with your meal. One pilot study found that a <a href="https://doi.org/10.2337/db22-836-P">supplement containing a blend of fibers</a> decreased the blood sugar spike – an increase in glucose levels in the blood that if <a href="https://doi.org/10.1017/S0029665122000088">too high can damage the body over time</a> – after a meal in healthy individuals by roughly 30%.</p>
<h2>Listen to your body</h2>
<p>While almost all fiber is generally good for health in most people, not all fiber affects the <a href="https://gutbites.org/2022/05/01/are-all-fibers-to-be-plated-equal/">body in the same way</a>. Consuming a <a href="https://doi.org/10.1111/apt.15129">range of different types</a> of fiber generally helps ensure a <a href="https://theconversation.com/hangry-bacteria-in-your-gut-microbiome-are-linked-to-chronic-disease-feeding-them-what-they-need-could-lead-to-happier-cells-and-a-healthier-body-199486">diverse microbiome</a>, which is linked to gut and overall health.</p>
<p>But certain medical conditions might preclude consuming certain types of fiber. For example, some people can be particularly sensitive to one <a href="https://doi.org/10.1136/gutjnl-2021-326284">class of fiber called FODMAPS</a> – fermentable oligosaccharides, disaccharides, monosaccharides and polyols – that are more readily fermented in the upper part of the gut and can contribute to symptoms of irritable bowel syndrome like bloating and diarrhea. <a href="https://www.health.harvard.edu/diseases-and-conditions/a-new-diet-to-manage-irritable-bowel-syndrome">High-FODMAP foods</a> include many processed foods that contain inulin, garlic powder and onion powder, as well as whole foods including those in the onion family, dairy products, some fruits and vegetables.</p>
<p>Listen to how your body responds to different high-fiber foods. Start low and go slow as you reintroduce foods like beans, seeds, nuts, fruits and vegetables to your diet. If you have trouble increasing your fiber intake, talk with your health care provider.</p>
<p>Tools like this <a href="https://gutbites.org/carb-fiber-ratio-calculator/">online calculator</a> I’ve created can also help you find the highest-quality foods with healthy fiber and other nutrient ratios. It can also show you what proportions of fiber to add back to sugary foods to help achieve healthy ratios.</p>
<p>I wouldn’t endorse eating sweets all the time, but as my three daughters like to remind me, it’s important to enjoy yourself every once in a while. And when you do, consider putting the carbs back in their fiber wrappers. It’s hard to improve upon nature’s design.</p><img src="https://counter.theconversation.com/content/205159/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Damman is on the scientific advisory board at BCD Biosciences and Supergut.</span></em></p>
Many processed foods strip carbs of their natural fibers. Eating foods with an ideal total carbohydrate-to-fiber ratio can help with weight management and improve overall health.
Christopher Damman, Associate Professor of Gastroenterology, School of Medicine, University of Washington
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/197416
2023-01-11T19:08:43Z
2023-01-11T19:08:43Z
Stop hating on pasta – it actually has a healthy ratio of carbs, protein and fat
<figure><img src="https://images.theconversation.com/files/503943/original/file-20230111-13-a23ca3.jpg?ixlib=rb-1.1.0&rect=35%2C26%2C5955%2C3961&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://images.pexels.com/photos/1279330/pexels-photo-1279330.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2">Pexels</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>New year, new you, new diet. It’s a familiar refrain. One popular dieting technique is to create a food blacklist. Quitting “carbs” or packaged foods is common, which can mean avoiding supermarket staples like pasta. </p>
<p>But do we really need to ban pasta to improve our diets? </p>
<p>This is what we call a reductionist approach to nutrition, where we describe a food based on just one of its key components. Pasta isn’t just carbohydrates. One cup (about 145 grams) of cooked pasta has about <a href="https://www.foodstandards.gov.au/science/monitoringnutrients/afcd/Pages/fooddetails.aspx?PFKID=F006456">38g of carbohydrates</a>, 7.7g of protein and 0.6g of fats. Plus, there’s all the water that is absorbed from cooking and lots of vitamins and minerals. </p>
<p>“But pasta is mostly carbs!” I hear you cry. This is true, but it’s not the whole story. We need to think about context. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ive-indulged-over-the-holidays-if-im-healthy-the-rest-of-the-time-does-it-matter-195643">I've indulged over the holidays. If I'm healthy the rest of the time, does it matter?</a>
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</em>
</p>
<hr>
<h2>Your day on a plate</h2>
<p>You probably know there are <a href="https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/dietary-energy">recommendations</a> for how much energy (kilojoules or calories) we should eat in a day. These recommendations are based on body size, sex and physical activity. But you might not realise there are also recommendations about the profile of macronutrients – or types of food – that supply this energy. </p>
<p>Fats, carbs and proteins are macronutrients. Macronutrients are broken down in the body to produce energy for our bodies.</p>
<p><a href="https://www.eatforhealth.gov.au/nutrient-reference-values/chronic-disease/macronutrient-balance">Acceptable Macronutrient Distribution Ranges</a> describe the ratio or percentage of macronutrients that should provide this energy. These ranges are set by experts based on health outcomes and models of healthy eating. They aim to make sure we get enough, but not too much, of each macro. Consuming too much or too little of any type of food can have consequences for health. </p>
<p>The ratios are also designed to make sure we get enough of the vitamins and minerals that come with the energy in the foods we typically eat. We should get 45–65% of our energy from carbohydrates, 10–30% from proteins, and 20–35% from fats.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="uncooked ravioli" src="https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/503955/original/file-20230111-26-4nnamw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If weight loss is a health goal, then looking at serving might be better than blacklisting food types.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1465911817134-741b5e473a1b?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1774&q=80">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-the-carnivore-diet-and-is-it-a-bad-idea-189464">What is the 'carnivore diet' and is it a bad idea?</a>
</strong>
</em>
</p>
<hr>
<h2>Mangia pasta</h2>
<p>Macronutrient ratios mean it can be healthy to eat up to between 1.2 and 6.5 times more carbohydrates in a day than protein – since each gram of protein has the same amount of energy as a gram of carbohydrates. </p>
<p>The ratio of carbs to protein in pasta is 38g to 7.7g, which equates to roughly a 5:1 ratio, well within the acceptable macronutrient distribution range. Meaning pasta actually has enough protein to balance with the carbohydrates. This isn’t just because of the eggs in pasta either. Wheat is another source of protein, making up about <a href="https://link.springer.com/chapter/10.1007/978-3-030-90673-3_4">20% of the proteins eaten</a> globally. </p>
<p>If you are worried about the calorie levels and weight gain, that’s not so simple either. </p>
<p>In the context of an otherwise healthy diet, people have been shown to <a href="https://bmjopen.bmj.com/content/bmjopen/8/3/e019438.full.pdf">lose more weight</a> when their diet includes pasta regularly. And, a <a href="https://www.sciencedirect.com/science/article/pii/S0939475317301606">systematic review</a> of ten different studies found pasta was better for post-meal blood glucose levels than bread or potatoes. </p>
<p>Instead of quitting spaghetti, consider reducing portion sizes, or switching to wholegrain pasta, which has a higher fibre content which has <a href="https://www.sciencedirect.com/science/article/abs/pii/S0195666316303166">benefits</a> for gut health and can help you feel fuller longer. </p>
<p>Gluten-free pasta has <a href="https://www.nutritionvalue.org/Pasta%2C_gluten_free_56140100_nutritional_value.html#:%7E:text=Pasta%2C%20gluten%20free%20contains%20251,mg%20of%20cholesterol%20per%20serving.">slightly less protein</a> than wheat pasta. So, despite being healthier for people with gluten intolerance, there are no increased health benefits in switching to gluten-free pasta for most of us. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Plate of flat pasta with broccoli and ham" src="https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/503946/original/file-20230111-14-b31ru3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pasta really is better the next day. Leftovers are lower in calories when cooled and reheated.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1607118750694-1469a22ef45d?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=2787&q=80">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-serving-sizes-on-food-labels-dont-tell-us-how-much-we-should-eat-123755">No, serving sizes on food labels don't tell us how much we should eat</a>
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</p>
<hr>
<h2>Pass the pesto and the leftover bolognese</h2>
<p>Pasta is also not typically eaten alone. So, while some warn about the dangers of blood sugar spikes when eating “<a href="https://loseitblog.com/2019/11/23/dressing-up-naked-carbs-to-make-more-filling-meals-and-snacks/#:%7E:text=Naked%20carbs%20are%20simple%20carbohydrates,a%20glass%20of%20fruit%20juice.">naked carbs</a>” (meaning just carbs with no other foods), this typically isn’t a risk for pasta. </p>
<p>When pasta provides the base of a meal, it can be a vehicle to help people eat more vegetables in smooth or chunky vegetable sauces. For kids (or fussy adults) pasta sauce can be a great place to <a href="https://www.bbcgoodfood.com/recipes/pasta-tomato-hidden-veg-sauce">hide pureed or grated vegetables</a>. </p>
<p>Not eating pasta alone is also important for the protein profile. Plant foods are typically not <a href="https://www.healthline.com/nutrition/incomplete-protein#definition">complete proteins</a>, which means we need to eat combinations of them to get all the different types of amino acids (the building blocks of proteins) we need to survive. </p>
<p>But pasta, even though we often focus on the carbs and energy, packs a good nutritional punch. Like most foods, it isn’t just macronutrients it also has micronutrients. </p>
<p><a href="https://www.foodstandards.gov.au/science/monitoringnutrients/afcd/Pages/fooddetails.aspx?PFKID=F006456">One cup</a> of cooked pasta has about a quarter of our daily recommended intakes of vitamins B1 and B9, half the recommended intake of selenium, and 10% of our iron needs. </p>
<p>The news for pasta gets even better when we eat it as leftovers. When pasta is cooked and cooled, some of the carbohydrates <a href="https://pubs.rsc.org/en/content/articlehtml/2020/fo/d0fo00849d">convert to resistant starch</a>. This starch gets its name from being resistant to digestion, so it contributes less energy and is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7022949/">better for blood sugar levels</a>. So, your leftover pasta, even if you reheat it, is lower in calories than the night before.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="colourful donuts on plate" src="https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/503952/original/file-20230111-22-dw9ckv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pasta offers more in nutritional terms than some other ‘carb’ foods.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1516919549054-e08258825f80?ixlib=rb-4.0.3&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=1770&q=80">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Look a little closer at ‘carb’ choices</h2>
<p>There is a lot of talk about reducing intakes of carbohydrates for weight loss, but remember carbs come in different forms and in different foods. </p>
<p>Some of them, like pasta, bring other benefits. Others like cakes and lollies, add very little else. When we talk about reducing intake of refined carbohydrates, think first of sweets that are eaten alone, before you cut the staple carbohydrates that are often served with vegetables – arguably the healthiest core food group!</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-to-work-out-how-much-food-you-should-eat-30894">Health Check: how to work out how much food you should eat</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/197416/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Emma Beckett has received funding for research or consulting from Mars Foods, Nutrition Research Australia, NHMRC, ARC, AMP Foundation, Kellogg, and the University of Newcastle. She is a member of committees/working groups related to nutrition or the Australian Academy of Science, the National Health and Medical Research Council and the Nutrition Society of Australia.</span></em></p>
Low carb diets are popular and pasta is often in the firing line for those who think it might contribute to weight gain. But your favourite dinner is being unfairly maligned!
Emma Beckett, Senior Lecturer (Food Science and Human Nutrition), School of Environmental and Life Sciences, University of Newcastle
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/184128
2022-08-22T12:26:15Z
2022-08-22T12:26:15Z
Two surprising reasons behind the obesity epidemic: Too much salt, not enough water
<figure><img src="https://images.theconversation.com/files/471724/original/file-20220629-12-h11vd4.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3600%2C2398&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Salty french fries may taste good, but they just contribute to dehydration and obesity.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/cropped-image-of-tempted-boy-holding-french-fries-royalty-free-image/660559557?adppopup=true">William Voon/EyeEm via Getty Images</a></span></figcaption></figure><p>Scientific studies and <a href="https://www.washingtonpost.com/health/what-percent-young-adults-obese/2021/12/03/b6010f98-5387-11ec-9267-17ae3bde2f26_story.html">media coverage</a> are rife <a href="https://doi.org/10.1002/oby.22073">with warnings</a> on how <a href="https://doi.org/10.31883/pjfns/110735">sugar</a>, <a href="https://doi.org/10.1111/jhn.12559">carbohydrates</a>, <a href="https://doi.org/10.3945/jn.111.153460">saturated fat</a> and <a href="https://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/physical-activity-and-obesity/">lack of exercise</a> contribute to obesity. And <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7721435/">tens of millions of Americans are still overweight or obese</a> in large part because of the classic Western diet and lifestyle. </p>
<p>As an <a href="https://drrichardjohnson.com/about/#">educator, researcher and professor of medicine</a>, I have <a href="https://drrichardjohnson.com/books/">spent more than 20 years</a> <a href="https://scholar.google.com/citations?user=dTgECeMAAAAJ&hl=en">investigating the causes of obesity</a>, as well as related conditions such as diabetes, high blood pressure and chronic kidney disease. </p>
<p>Throughout my many years of studying obesity and related health conditions, I’ve observed that relatively little is said about two significant pieces of this very complex puzzle: lack of hydration and excessive salt intake. Both are known to contribute to obesity. </p>
<h2>Lessons learned from a desert sand rat</h2>
<p>Nature provides a clue to the role these factors play with the desert sand rat <em>Psammomys obesus</em>, a half-pound rodent with a high-pitched squeak that lives in the salty marshes and deserts of Northern Africa. It survives, barely, by eating the stems of <em>Salicornia</em> – the glasswort – a plant that looks a bit like asparagus. </p>
<p>Although low in nutrients, the glasswort’s fleshy, succulent sap is filled with water that’s rich in salt, at concentrations as high as what’s found in seawater.</p>
<p>Recent studies <a href="https://doi.org/10.1073/pnas.1713837115">have provided new insights</a> into why the desert sand rat might crave the salty sap of glasswort. Although this has not yet been proven specifically in the sand rat, it is likely that a high-salt diet helps the sand rat convert the relatively low amount of carbohydrates it’s ingesting into fructose, a type of sugar that occurs naturally in fruits, honey and some vegetables.</p>
<p>This <a href="https://doi.org/10.1111/joim.12993">helps the animal survive</a> when food and fresh water are sparse. This is because fructose activates a “survival switch” that stimulates foraging, food intake and the storage of fat and carbohydrates that protect the animal from starvation.</p>
<p>However, when the rat is brought into captivity and given the common rodent diet of about 50% carbohydrates, it <a href="https://doi.org/10.1152/ajplegacy.1965.208.2.297">rapidly develops obesity and diabetes</a>. But if given fresh vegetables low in starchy carbohydrates, the rodent remains lean. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A desert sand rat, with prominent whiskers and a brown and white coat, takes a look outside its burrow." src="https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471738/original/file-20220629-21-kvfn1y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The desert sand rat, also known as the fat sand rat, is actually a gerbil. It’s found in Asia as well as Africa.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/fat-sand-rat-emerging-from-burrow-in-coastal-royalty-free-image/617548398?adppopup=true">Kristian Bell/Moment via Getty Images</a></span>
</figcaption>
</figure>
<p><a href="https://drrichardjohnson.com/books/">My research</a>, and the research of many other scientists over the decades, shows that many Americans unwittingly behave much like a captive desert sand rat, although few are in settings where food and water are limited. They are constantly activating the survival switch. </p>
<h2>Fructose and our diets</h2>
<p>As mentioned, fructose, a simple sugar, appears to have a key role in activating this survival switch that leads to fat production.</p>
<p>Small amounts of fructose, like that found in an individual fruit, are not the problem – rather it is excessive amounts of fructose that are problematic for human health. Most of us get our fructose from table sugar and high-fructose corn syrup. Intake of these two sugars <a href="https://www.usatoday.com/story/news/world/2014/03/05/five-percent-of-calories-should-be-from-sugar/6097623/">totals approximately 15% of calories</a> in the average American diet. </p>
<p>These sugars encourage people to eat more, which can lead to <a href="https://doi.org/10.1038/s41574-021-00627-6">weight gain, fat accumulation and prediabetes</a>. </p>
<p>Our bodies also make fructose on their own – and experimental studies suggest it may be enough to <a href="https://doi.org/10.1074/jbc.RA118.006158">trigger the development of obesity</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A spoonful of sugar, surrounded by sugar cubes, on a wooden table." src="https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=461&fit=crop&dpr=1 600w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=461&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=461&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=579&fit=crop&dpr=1 754w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=579&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/468593/original/file-20220613-17-sgohui.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=579&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Table sugar and high-fructose corn syrup are two of the culprits that can cause weight gain and obesity.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/sugar-spoon-on-wood-royalty-free-image/681197933?adppopup=true">ATU Images/The Image Bank via Getty Images</a></span>
</figcaption>
</figure>
<p>Since fructose is made from glucose, production of fructose increases when blood glucose levels are high. This process happens when we eat a lot of rice, cereal, potatoes and white bread; those are carbs that rapidly release glucose into the blood rapidly.</p>
<p>And notably, fructose production can also <a href="https://doi.org/10.1074/jbc.RA118.006158">be stimulated by dehydration</a>, which drives fat production. </p>
<h2>Fat provides water</h2>
<p>Fat has two major functions. The first one, which is well known, is to store calories for a later time when food is unavailable. </p>
<p>The other major but lesser-known function of fat <a href="https://doi.org/10.1681/ASN.2015121314">is to provide water</a>. </p>
<p>To be clear, fat does not contain water. But when fat breaks down, it generates water in the body. The amount produced is substantial, and roughly equivalent to the amount of fat burned. It’s so significant that some animals <a href="https://doi.org/10.1681/ASN.2015121314">rely on fat to provide water</a> during times when it’s not available. </p>
<p>Whales are but one example. While they drink some seawater, they get most of their water from the foods they eat. And when they go for extended periods without food, they get their water <a href="https://doi.org/10.1242/jeb.204.11.1831">primarily by metabolizing fat</a>. </p>
<h2>Hold the fries</h2>
<p>The role of dehydration as a contributor to obesity should not be underestimated. It commonly occurs after eating salty foods. Both dehydration and salt consumption lead to <a href="https://doi.org/10.1073/pnas.1713837115">the production of fructose and fat</a>. </p>
<p>This is why salty french fries are especially fattening. The salt causes a dehydration-like state that encourages the conversion of the starch in the french fry to fructose.</p>
<p>What’s more, studies show most people who are overweight or obese <a href="https://doi.org/10.1038/sj.ejcn.1602521">don’t drink enough water</a>. They are far more likely to be dehydrated than those who are lean. Their salt intake is also very high compared with lean people’s. </p>
<p>Research shows that people with obesity frequently <a href="https://doi.org/10.1038/ijo.2012.88">have high levels of vasopressin</a>, a hormone that helps the kidneys hold water to regulate urine volume. </p>
<p>But recent studies suggest vasopressin has another purpose, which is <a href="https://doi.org/10.1172/jci.insight.140848">to stimulate fat production</a>. </p>
<p>For someone at risk of dehydration or starvation, vasopressin may have a real survival benefit. But for those not at risk, vasopressin could drive most of the metabolic effects of excess fructose, like weight gain, fat accumulation, fatty liver and prediabetes. </p>
<h2>Drinking more water</h2>
<p>So does this mean drinking more water can help us lose weight? The medical community has <a href="https://www.nytimes.com/2021/09/17/well/live/how-much-water-should-I-drink.html">often scoffed at the assertion</a>. However, our research team found that giving mice more water slowed <a href="https://doi.org/10.1172/jci.insight.140848">weight gain and the development of prediabetes</a>, even when the mice had diets rich in sugar and fat. </p>
<p>There is also increasing evidence that <a href="https://doi.org/10.3390/nu14102070">most people drink too little water</a> in general, and increasing water intake may help people who are obese <a href="https://doi.org/10.1038/oby.2008.409">lose weight</a>. </p>
<p>That’s why I encourage drinking eight tall glasses of water a day. And eight is likely enough; don’t assume more is better. There have been cases of people drinking so much that “water intoxication” occurs. This is particularly a problem with people who have heart, kidney or liver conditions, as well as those who have had recent surgery or <a href="https://doi.org/10.1056/NEJMoa043901">are long-distance runners</a>. It’s always good to first check with your doctor about water intake. </p>
<p>For the desert sand rat, and for our ancestors who scavenged for food, a high-salt and limited-water diet made sense. But human beings no longer live that way. These simple measures – drinking more water and reducing salt intake – offer cheap, easy and healthy strategies that may prevent or treat obesity.</p><img src="https://counter.theconversation.com/content/184128/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Johnson is a Professor of Medicine at the University of Colorado Anschutz Medical Campus who has received funding from the National Institutes of Health, Veteran's Health Administration, and Department of Defense to understand the role of fructose metabolism in a variety of metabolic disorders. He also has equity with Colorado Research Partners LLC that is developing inhibitors of fructose metabolism. He is also author of Nature Wants Us to Be Fat (Benbella books, 2022) that discusses the science of fructose and its role in obesity and metabolic disorders.</span></em></p>
Studies show that most people who are overweight or obese are also chronically dehydrated.
Richard Johnson, Professor of Medicine, University of Colorado Anschutz Medical Campus
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/181263
2022-06-08T20:20:46Z
2022-06-08T20:20:46Z
‘Food sequencing’ really can help your glucose levels. Here’s what science says about eating salad before carbs
<figure><img src="https://images.theconversation.com/files/462659/original/file-20220512-24-a8w7cx.jpg?ixlib=rb-1.1.0&rect=0%2C4%2C1000%2C661&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/healthy-vegan-lunch-bowl-avocado-quinoa-604314275">Shutterstock</a></span></figcaption></figure><p>Biochemist and author of the <a href="https://www.glucose-revolution.com">Glucose Revolution</a> Jessie Inchauspé says tweaking your diet can change your life.</p>
<p>Among her recommendations in the <a href="https://www.abc.net.au/radionational/programs/lifematters/talkback:-could-changing-your-glucose-intake-change-your-life/13791024">mainstream media</a> and <a href="https://www.instagram.com/glucosegoddess/?hl=en">on Instagram</a>, the founder of the “<a href="https://www.glucose-revolution.com">Glucose Goddess movement</a>” says eating your food in a particular order is the key. </p>
<p>By eating salads first, before proteins, and finishing the meal with starchy carbohydrates, she says blood glucose spikes will be flattened, which is better for you.</p>
<p>Scientifically speaking, does this make sense? It turns out, yes, partially.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lemon-water-wont-detox-or-energise-you-but-it-may-affect-your-body-in-other-ways-180035">Lemon water won't detox or energise you. But it may affect your body in other ways</a>
</strong>
</em>
</p>
<hr>
<h2>What is a glucose spike?</h2>
<p>A glucose spike occurs in your bloodstream <a href="https://www.sciencedirect.com/science/article/pii/S0261561419301542">about 30-60 minutes</a> after you eat carbohydrate. Many things determine how high and how long the peak lasts. These include what you ate with or before the carbohydrate, how much fibre is in the carbohydrate, and your body’s ability to secrete, and use, the hormone insulin.</p>
<p>For people with certain medical conditions, any tactic to flatten the glucose peak is incredibly important. These conditions include: </p>
<ul>
<li><p>diabetes</p></li>
<li><p>reactive hypoglycaemia (a particular type of recurring sugar crash)</p></li>
<li><p>postprandial hypotension (low blood pressure after eating) or </p></li>
<li><p>if you’ve had bariatric surgery. </p></li>
</ul>
<p>That’s because high and prolonged glucose spikes have lasting and detrimental impacts on many hormones and proteins, including those that trigger inflammation. Inflammation is linked with a range of conditions including diabetes and heart disease.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/got-pre-diabetes-heres-five-things-to-eat-or-avoid-to-prevent-type-2-diabetes-80838">Got pre-diabetes? Here's five things to eat or avoid to prevent type 2 diabetes</a>
</strong>
</em>
</p>
<hr>
<h2>Different foods, different spikes</h2>
<p>Does eating different food types before carbs affect glucose spikes? Turns out, yes. This isn’t new evidence either. </p>
<p>Scientists have known for a long time that high-fibre foods, such as salads, slow gastric emptying (the rate at which food exits the stomach). So high-fibre foods <a href="https://link.springer.com/article/10.1186/1475-2891-9-58">slow the delivery</a> of glucose and other nutrients to the small intestine for absorption into the blood.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Stomach and small intestines" src="https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462675/original/file-20220512-21-exx33b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Salads slow down the movement of food from your stomach into your small intestine.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-illustration-human-digestive-system-anatomy-1898319229">Shutterstock</a></span>
</figcaption>
</figure>
<p>Proteins and fats <a href="https://diabetesjournals.org/care/article/32/9/1600/28666/Effects-of-a-Protein-Preload-on-Gastric-Emptying">also slow</a> gastric emptying. Protein has the extra advantage of stimulating a hormone called glucagon-like-peptide 1 (or GLP1). When protein from your food hits the cells in your intestines, this hormone is secreted, slowing gastric emptying even further. The hormone also affects the pancreas where it helps secretion of the hormone insulin that mops up the glucose in your blood. </p>
<p>In fact, drugs that mimic how GLP1 works (known as <a href="https://www.diabetesaustralia.com.au/living-with-diabetes/medicine/injectables/">GLP1 receptor agonists</a>) are a new and very effective class of medication for people with type 2 diabetes. They’re making a real difference to improve their blood sugar control.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/these-4-diets-are-trending-we-looked-at-the-science-or-lack-of-it-behind-each-one-136045">These 4 diets are trending. We looked at the science (or lack of it) behind each one</a>
</strong>
</em>
</p>
<hr>
<h2>What about eating food in sequence?</h2>
<p>Most of the scientific research on whether eating food in a particular order makes a difference to glucose spikes involves giving a fibre, fat or protein “preload” before the meal. Typically, the preload is a liquid and given around 30 minutes before the carbohydrate.</p>
<p>In <a href="https://diabetesjournals.org/care/article/32/9/1600/28666/Effects-of-a-Protein-Preload-on-Gastric-Emptying">one study</a>, drinking a whey protein shake 30 minutes before (rather than with) a mashed potato meal was better at slowing gastric emptying. Either option was better at reducing the glucose spike than drinking water before the meal.</p>
<p>While this evidence shows eating protein before carbohydrates helps reduce glucose spikes, the evidence for eating other food groups separately, and in sequence, during an average meal is not so strong.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Steak on flame-grill barbecue" src="https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462678/original/file-20220512-18-odqy2g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A steak takes longer than mash to churn into a size ready for the small intestine.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/grilling-steaks-on-flaming-grill-shot-397498693">Shutterstock</a></span>
</figcaption>
</figure>
<p>Inchauspé <a href="https://www.abc.net.au/radionational/programs/lifematters/talkback:-could-changing-your-glucose-intake-change-your-life/13791024">says</a> fibre, fats, and proteins don’t mix in the stomach – they do. But nutrients don’t exit the stomach until they have been churned into a fine particle size.</p>
<p>Steak takes longer than mash to be churned into a fine particle. Given the additional fact that liquids empty faster than solids, and people tend to complete their entire dinner in around 15 minutes, is there any real evidence that eating a meal within a particular sequence will be more beneficial than eating the foods, as you like, and all mixed up on the plate?</p>
<p>Yes, but it is not very strong. </p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S0261561419301542">One small study</a> tested five different meal sequences in 16 people without diabetes. Participants had to eat their meal within 15 minutes. </p>
<p>There was no overall difference in glucose spikes between groups that ate their vegetables before meat and rice versus the other sequences.</p>
<h2>What’s the take-home message?</h2>
<p>Watching those glucose spikes is particularly important if you have
diabetes or a handful of other medical conditions. If that’s the case, your treating doctor or dietitian will advise how to modify your meals or food intake to avoid glucose spikes. Food ordering may be part of that advice.</p>
<p>For the rest of us, don’t tie yourself up in knots trying to eat your meal in a particular order. But do consider removing sugary beverages, and adding fibre, proteins or fats to carbohydrates to slow gastric emptying and flatten glucose spikes.</p><img src="https://counter.theconversation.com/content/181263/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Leonie Heilbronn currently receives funding from Medical Research Futures Fund and National Health and Medical Research Council, and Isagenix LLT. </span></em></p>
It sounds too good to be true. But the science on how different types of foods affect your glucose levels has been known for a long time.
Leonie Heilbronn, Professor and Group Leader, Obesity & Metabolism, University of Adelaide
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/179454
2022-05-19T12:23:24Z
2022-05-19T12:23:24Z
Is intermittent fasting the diet for you? Here’s what the science says
<figure><img src="https://images.theconversation.com/files/453968/original/file-20220323-23-zm8qqm.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6000%2C3997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Intermittent fasting could have an array of health benefits, but as of yet there are no long-term studies into its effects.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/intermitted-farsting-diet-concept-royalty-free-image/1361961784?adppopup=true">neirfy/iStock via Getty Images Plus</a></span></figcaption></figure><p>What if I told you all you need to do to lose weight is read a calendar and tell time? These are the basics for successfully following an intermittent fasting diet. </p>
<p>Can it be that simple, though? Does it work? And what is the scientific basis for fasting? As a registered dietitian and <a href="https://experts.okstate.edu/mckale.montgomery">expert in human nutrition and metabolism</a>, I am frequently asked such questions.</p>
<p>Simply stated, intermittent fasting is defined by alternating set periods of fasting with periods in which eating is permitted. One method is <a href="https://doi.org/10.1093/ajcn/86.1.7">alternate-day fasting</a>. On “fast days,” followers of this form of fasting are restricted to consuming no more than 500 calories per day; on “feast days,” which occur every other day, they can eat freely, with no restrictions on the types or quantities of foods eaten. </p>
<p>Other methods include the increasingly popular <a href="https://doi.org/10.1038/s41574-022-00638-x">5:2 method</a>. This form of fasting involves five days of feasting and two days of fasting per week. </p>
<p>Another variation relies on time-restricted eating. That means followers should fast for a specified number of hours – typically 16 to 20 per day – while freely consuming foods within a designated four- to eight-hour period.</p>
<p>But what about eating breakfast and <a href="https://doi.org/10.1056/NEJM198910053211403">then small meals throughout</a> the day to keep the body’s metabolism running? After all, that’s the <a href="https://doi.org/10.1093/ajcn/81.1.16">conventional wisdom</a> that many of us grew up with. </p>
<p>To answer these questions, it helps to understand the basics of human metabolism. </p>
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<figcaption><span class="caption">A TV host went on a two-month intermittent fast to lose weight. Did it work?</span></figcaption>
</figure>
<h2>Human metabolism 101</h2>
<p>The human body requires a continual supply of energy to sustain life, and the foods we eat provide us with this energy. But because eating is often followed by periods of time without eating, an intricate set of biological pathways is in place to meet the body’s energy demands between meals. </p>
<p>Most of the pathways function at some level all the time, but they fluctuate following a meal in a predictable pattern called the <a href="https://doi.org/10.1007/s13679-018-0308-9">fed-fast cycle</a>. The time frames of the cycle can vary, depending on the food types eaten, the size of the meal and the person’s activity level.</p>
<p>So what happens, metabolically speaking, after we eat? Consuming carbohydrates and fats leads to a rise in blood glucose and also <a href="https://doi.org/10.1001/jama.2013.280593">lipid levels</a>, which include cholesterol and triglycerides. </p>
<p>This triggers the release of insulin from the pancreas. The insulin helps tissues throughout the body take up the glucose and lipids, which supplies the tissues with energy. </p>
<p>Once energy needs are met, leftover glucose is stored in the liver and skeletal muscle in a condensed form called glycogen. When glycogen stores are full, excess glucose converts to fatty acids and is stored in fat tissue. </p>
<p><a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/absorptive-state">About three to 18 hours</a> after a meal – again, depending upon a person’s activity level and size the of the meal – the amount of circulating blood glucose and lipids returns to baseline levels. So tissues then must rely on fuel sources already in the body, which are the glycogen and fat. A hormone called glucagon, secreted by the pancreas, helps facilitate the breakdown of glycogen and fat to provide energy for the body between meals. </p>
<p>Glucagon also initiates a process known as <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/gluconeogenesis">gluconeogenesis</a>, which is the synthesis of glucose from nondietary sources. This helps maintain the right level of blood glucose levels.</p>
<p>When the body reaches a true fasting state – about 18 hours to two days without additional food intake – the body’s stores of glycogen are depleted, and tissues like the heart and skeletal muscle start to rely heavily on fats for energy. That means an increase in the breakdown of the stored fats. </p>
<p>“Aha!” you might say. “So intermittent fasting is the key to ultimate fat burning?” Well, it’s not that simple. Let’s go through what happens next.</p>
<h2>The starvation state</h2>
<p>Though many tissues adapt to using fats for energy, the brain and red blood cells need a continual supply of glucose. But when glucose is not available because of fasting, the body starts to break down its own proteins and <a href="https://doi.org/10.1152/ajpendo.1997.273.6.E1209">converts them to glucose instead</a>. However, because proteins are also critical for supporting essential bodily functions, this is not a sustainable process.</p>
<p>When the body enters the starvation state, the body goes into self-preservation mode, and a metabolic shift occurs in an effort to spare body protein. The body continues to synthesize glucose for those cells and tissue that absolutely need it, but the breakdown of stored fats increases as well to provide energy for tissues such as the skeletal muscle, heart, liver and kidneys. </p>
<p>This also <a href="https://www.ncbi.nlm.nih.gov/books/NBK493179/#">promotes ketogenesis</a>, or the formation of ketone bodies – molecules produced in the liver as an energy source when glucose is not available. In the starvation state, ketone bodies are important energy sources, because the body is not capable of solely utilizing fat for energy. This is why it is inaccurate when some proponents of intermittent fasting claim that fasting is a way of burning “just fat” - it’s not biologically possible.</p>
<p>What happens when you break the fast? The cycle starts over. Blood glucose and lipids return to basal levels, and energy levels in the body are seamlessly maintained by transitioning between the metabolic pathways described earlier. The neat thing is, we don’t even have to think about it. The body is well-equipped to adapt between periods of feasting and fasting. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/G5J6BfFMZPM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Intermittent fasting – fact or fiction? What the science actually says.</span></figcaption>
</figure>
<h2>Possible downsides</h2>
<p>If an “all-or-nothing” dietary approach to weight loss sounds appealing to you, chances are it just might work. Indeed, intermittent fasting diets have produced <a href="https://doi.org/10.1001/jamainternmed.2017.0936">clinically significant</a> amounts of weight loss. Intermittent fasting may also <a href="https://doi.org/10.1038/s41574-022-00638-x">reduce disease risk</a> by lowering blood pressure and blood lipid levels.</p>
<p>On the flip side, numerous studies have shown that the weight reduction from intermittent fasting diets is <a href="https://doi.org/10.1001/jamainternmed.2017.0936">no greater than</a> the weight loss on a standard calorie-restricted diet.</p>
<p>In fact, the weight loss caused by intermittent fasting is due not to spending time in some sort of magic metabolic window, but rather to reduced overall calorie consumption. On feast days, dieters do not typically <a href="https://doi.org/10.1186/1475-2891-9-35">fully compensate</a> for lack of food on fasted days. This is what results in mild to moderate weight loss. Approximately 75% of the weight is fat mass; the rest is lean mass. That’s about the <a href="https://doi.org/10.1038/s41574-022-00638-x">same ratio as a standard low-calorie diet</a>.</p>
<p>Should you still want to go forward with intermittent fasting, keep a few things to keep in mind. First, there are no studies on the long-term safety and efficacy of following this type of diet. Second, studies show that intermittent fasters don’t get enough of <a href="https://doi.org/10.1016/j.clnu.2020.02.022">certain nutrients</a>. </p>
<p>Exercise is something else to consider. It helps preserve lean muscle mass and may also contribute to increased weight loss and long-term weight maintenance. This is important, because nearly a quarter of the weight lost on any diet is muscle tissue, and the efficacy of intermittent fasting for weight loss has been demonstrated <a href="https://doi.org/10.1038/s41574-022-00638-x">for only short durations</a>.</p>
<p>Also, once you stop following an intermittent-fasting diet, you will very likely gain the weight back. This is a critical consideration, because many people find the diet difficult to follow long-term. Imagine the challenge of planning six months’ worth of feasting and fasting around family dinners, holidays and parties. Then imagine doing it for a lifetime. </p>
<p>Ultimately, the best approach is to follow an eating plan that meets current dietary recommendations and fits into your lifestyle.</p><img src="https://counter.theconversation.com/content/179454/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>McKale Montgomery receives funding from the National Institutes of Health.</span></em></p>
Proponents of intermittent fasting say the clock can help you win the battle of the bulge. But the science behind it is a little more complicated.
McKale Montgomery, Assistant Professor of Nutritional Sciences, Oklahoma State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/176723
2022-02-24T12:22:10Z
2022-02-24T12:22:10Z
Biofuel: how new microalgae technologies can hasten the end of our reliance on oil
<figure><img src="https://images.theconversation.com/files/448064/original/file-20220223-25-1ev0gv8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6016%2C4016&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/photobioreactor-lab-algae-fuel-biofuel-industry-1427613143">Chokniti Khongchum/Shutterstock</a></span></figcaption></figure><p><a href="https://doi.org/10.1016/B978-0-12-800776-1.00002-9">Microalgae</a> have been used by the Chinese for <a href="https://doi.org/10.1016/B978-0-12-811405-6.00009-8">medicinal and nutritional</a> purposes for thousands of years in the belief they could cure almost any health condition. The idea that microalgae have extraordinary healing powers isn’t as far-fetched as some might think. Though the ancient Chinese believed the microalgae was responsible for health-improving benefits, we now know that it was in fact the biochemical compounds produced by these microscopic creatures that provided the “magic”.</p>
<p>There are approximately 100,000 species of microalgae, each with their own distinct set of properties. This diversity allows microalgae to flourish in almost every environment on Earth. Mostly they exist in aquatic habitats such as fresh or wastewater, but they have been found in moist soil – and even snowbanks too.</p>
<p>Microalgae are usually described as being green, and this is true for species such as <em>B. braunii</em> and <em>C. vulgaris</em>. But there are other species, such as <em>C. officinalis</em>, which is red or <em>F. spiralis</em>, which is brown. Each classification produces different types or quantities of biochemical compounds, making some more useful for certain applications than others.</p>
<p>Over the past few decades <a href="https://doi.org/10.1007/s11157-010-9214-7">research</a> has demonstrated the huge potential of microalgae, especially in the production of <a href="https://www.britannica.com/technology/biofuel">biofuel</a> – fuel that is created from plant material or animal waste. I wanted to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0048969721061891">review this research</a> to provide a framework to establish the most suitable microalgae species for large-scale biofuel production that can ultimately rival oil and gas giants and reduce our reliance on fossil fuels.</p>
<h2>The magic of micoalgae</h2>
<p>Microalgae have a unique ability to convert sunlight and carbon dioxide into a wide range of biochemical compounds. Despite being classed as animals, they metabolise the same way as plants, producing oxygen to replenish what we humans consume. This cycle acts as a carbon capture system, whereby harmful CO₂ in the atmosphere is converted to useful oxygen. Microalgae also produce a wide range of other compounds found inside the cells, and these are what make microalgae so good at combating the effects of global warming.</p>
<p>Generally, the products from microalgae can be grouped into three classes: proteins, carbohydrates and lipids (fats). But <a href="https://fbscience.com/Scholar/articles/10.2741/S490">research</a> has found that there are several other high-value biochemical compounds that have significant applications in a wide range of different industries. For example, microalgae produce compounds known as carotenoids, more commonly known as dyes or pigments. These compounds are responsible for giving salmon its pink colour, as the food they eat contains high quantities of carotenoids.</p>
<p>Another high-value class of compounds are <a href="https://medlineplus.gov/ency/patientinstructions/000747.htm">polyunsaturated fatty acids</a> (PUFA). These compounds are part of the lipid family and play a vital role in supplying the cells with energy. Microalgae have been deemed one of the richest sources of these compounds, which help treat the <a href="https://pubs.acs.org/doi/10.1021/np050354%2B">effects of diabetes and arthritis</a>.</p>
<p>But how is it possible for these organisms to produce oil that can be used in cars? The petrol and diesel currently used is derived from crude oil that was formed millions of years ago from dead sea creatures. But modern biofuel is produced from living organisms on a real-time basis. </p>
<h2>How biofuel is produced</h2>
<p>Biofuel made from microalgae is currently one of the most promising fossil fuel alternatives to sustain the world’s energy demand. This is no easy task, especially having to compete with a highly profitable industry that has been established for more than a century. But unlike oil, which is non-renewable, biofuel is a renewable and sustainable source of fuel. Unfortunately, the economics of biofuel can’t yet compete with traditional fossil fuels. It all boils down to the bottom line, and currently the scale-up technology required isn’t here yet. </p>
<p>Microalgae don’t directly produce biofuel – they produce lipids (fats). To make biofuel these fats must be converted through a process known as <a href="https://doi.org/10.1016/B978-0-08-102728-8.00007-3">transesterification</a>. The process involves removing as much water as possible, known as dewatering, but this requires significant amounts of energy, resulting in high operating costs. As a result, the overall process becomes too expensive to compete with the oil and gas industry, despite its positive environmental impact.</p>
<figure>
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<p>Economics aside, the future for microalgae cultivation and lipid extraction is extremely promising. The development of hybrid technologies will accelerate the global shift to reducing our reliance on fossil fuels. These include cell factories that use gold <a href="https://www.frontiersin.org/articles/10.3389/fbioe.2020.00990/full">nanoparticles</a> – subatomic particles similar to atoms that form the building blocks of physical matter – to increase production rates and increase efficiencies. </p>
<p>Another potential solution is a process known as “milking”. Traditional cultivation methods for microalgae mean they are destroyed after the cultivation period has ended, which limits the full potential of what each cell can offer. Just like milking a cow, the process can be repeated without killing the cow, and the same goes for microalgae. By repeatedly removing high-value compounds from the same culture of microalgae, the high production cost issues can be removed, resulting in a sustainable and scalable process for the future. </p>
<p>This would result in biofuel becoming cost competitive with current fossil fuels, helping to accelerate the shift towards alternative energy sources. Unfortunately, the prospect of competitive biofuel production has some way to go before it can rival fossil fuel prices and quantities. But these developing technologies have the potential to speed up the transition needed to help the world reach its 2050 emissions targets.</p><img src="https://counter.theconversation.com/content/176723/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Callum Russell does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
New developments in microalgae cultivation are helping to propel the potential of renewable biofuels to combat climate change.
Callum Russell, Chemical Engineering PhD, University of the West of Scotland
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/173992
2022-01-14T13:35:45Z
2022-01-14T13:35:45Z
Sugar detox? Cutting carbs? A doctor explains why you should keep fruit on the menu
<figure><img src="https://images.theconversation.com/files/440471/original/file-20220112-25-egh65j.jpg?ixlib=rb-1.1.0&rect=270%2C457%2C4193%2C2828&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ripe berries and sugar crystals are both sweet, but one offers much more than just calories.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/sugar-sprinkling-down-onto-a-spoonful-of-strawberries-taken-news-photo/138203565">Chris George/PhotoPlus Magazine/Future via Getty Images</a></span></figcaption></figure><p>One of my patients – who had been struggling with obesity, uncontrolled diabetes and the cost of her medications – agreed in June 2019 to adopt a more whole-food plant-based diet.</p>
<p>Excited by the challenge, she did a remarkable job. She increased her fresh fruit and vegetable intake, stopped eating candy, cookies and cakes and cut down on foods from animal sources. Over six months, she lost 19 pounds and her HbA1c – a measure of her <a href="https://www.cdc.gov/diabetes/managing/managing-blood-sugar/a1c.html">average blood sugar</a> – dropped from 11.5% to 7.6%.</p>
<p>She was doing so well, I expected that her HbA1c would continue to drop and she would be one of our plant-based successes who had reversed diabetes.</p>
<p>Her three-month follow-up visit in March 2020 was canceled because of COVID-19 lockdowns. When I eventually saw her again in May 2021, she’d regained some of the weight and her HbA1c had climbed to 10.4%. She explained that her diabetes doctor and a diabetes nurse educator had told her that she was eating too much “sugar” on the plant-based diet.</p>
<p>She’d been advised to limit carbohydrates by cutting back on fruits and starchy vegetables and eating more fish and chicken. Sugar-free candy, cakes, cookies and artificial sweeteners were encouraged. In the face of conflicting medical advice, she fell back on conventional wisdom that “sugar” is bad and should be avoided whenever possible, especially if you have diabetes. </p>
<p>I’m a physician, board certified in preventive medicine with a <a href="https://lifestylemedicine.org/What-is-Lifestyle-Medicine">lifestyle medicine</a> clinic at Morehouse Healthcare in Atlanta. This emerging medical specialty focuses on helping patients make healthy lifestyle behavior modifications. Patients who adopt whole-food plant-based diets increase carbohydrate intake and often see reversal of chronic diseases including diabetes and hypertension. In my clinical experience, myths about “sugar” and carbohydrates are common among patients and health professionals. </p>
<h2>Fruit vs. sugar</h2>
<p>Your body runs on glucose. It is the simple sugar that cells use for energy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="molecular diagrams for glucose, fructose and galactose" src="https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=140&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=140&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=140&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=176&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=176&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440472/original/file-20220112-19-1a13b8z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=176&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These molecules are the three kinds of simple sugars, found in starches, fruit and milk.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/biology-diagram-show-structure-and-formation-royalty-free-illustration/1247905133">Trinset/ iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Glucose is a molecular building block of <a href="https://open.oregonstate.education/animalnutrition/chapter/chapter-3/">carbohydrates</a>, one of the three essential <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7468865/">macronutrients</a>. The other two are fat and protein. Starches are long, branching chains of glucose.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="molecular diagram of chain of glucoses together" src="https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=78&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=78&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=78&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=98&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=98&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440473/original/file-20220112-21-k525qd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=98&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chains of simple sugar molecules linked together form starches and other carbohydrates.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/biology-diagram-show-structure-and-formation-royalty-free-illustration/1247905133">Trinset/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Naturally occurring carbohydrates travel in nutrient-dense packages such as fruits, vegetables, whole grains, nuts and seeds. </p>
<p>Humans <a href="https://theconversation.com/a-taste-for-sweet-an-anthropologist-explains-the-evolutionary-origins-of-why-youre-programmed-to-love-sugar-173197">evolved to crave sweet tastes</a> to get the nutrients needed to survive. A daily supply of vitamins, minerals and fiber is needed because our bodies cannot make them. The best source of these substances for our ancient ancestors was sweet, ripe, delicious fruit. In addition, fruits contain <a href="https://fruitsandveggies.org/stories/what-are-phytochemicals/">phytonutrients</a> and <a href="https://www.nccih.nih.gov/health/antioxidants-in-depth">antioxidants</a>, chemicals produced only by plants. Phytonutrients such as <a href="https://doi.org/10.1093/fqsafe/fyx023">ellagic acid in strawberries</a> have cancer-fighting properties and promote heart health. </p>
<p>Refined sugars, on the other hand, are highly processed and stripped of all nutrients except calories. They’re a concentrated form of carbohydrates. The food industry produces refined sugars in many forms. The most common are sucrose crystals, which you’d recognize as table sugar, and high-fructose corn syrup, which is found in many processed foods and sweetened beverages. </p>
<p>If you continually satisfy your taste for sweet with foods that contain refined sugar – rather than the nutrient-rich fruits at the core of this craving passed on by evolution – you <a href="https://doi.org/10.1136/openhrt-2016-000469">may not get all the nutrients you need</a>. Over time, this deficit may create a vicious cycle of overeating that leads to obesity and obesity-related health problems. Women who eat the most fruit <a href="https://doi.org/10.3945/jn.114.199158">tend to have lower rates of obesity</a>.</p>
<h2>Sugar toxicity</h2>
<p>Refined sugars are not directly toxic to cells, but they can combine with proteins and fats in food and in the bloodstream to produce toxic substances such as <a href="https://doi.org/10.3945/an.115.008433">advanced glycation end products</a> (AGEs). High blood glucose levels may produce <a href="https://doi.org/10.1046/j.1432-1033.2002.03017.x">glycated low-density lipoproteins</a>. High levels of these and other glucose-related toxic substances are associated with an increased risk of a wide range of chronic health problems, including <a href="https://doi.org/10.2337/dc17-1740">cardiovascular disease and diabetes</a>.</p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-youresmart">You can read us daily by subscribing to our newsletter</a>.]</p>
<p>The disease most commonly associated with sugar is Type 2 diabetes. A surprising number of people, including health professionals, incorrectly believe that eating sugar causes Type 2 diabetes. This myth leads to a focus on lowering blood sugar and “counting carbs” while ignoring the real cause: progressive <a href="https://doi.org/10.2337/dcS13-2008">loss of pancreatic beta cell function</a>. At diagnosis, a patient may have lost between <a href="https://doi.org/10.1016/S2213-8587(20)30022-X">40% and 60%</a> of their beta cells, which are responsible for producing insulin. </p>
<p>Insulin is a hormone that controls how much glucose is in the bloodstream by blocking glucose production in the liver and driving it into fat and muscle cells. Loss of beta cell function means not enough insulin gets produced, resulting in the high blood glucose levels characteristic of Type 2 diabetes.</p>
<p>Beta cells have <a href="https://doi.org/10.1007/s00424-010-0862-9">low levels of antioxidants and are susceptible to attack</a> by metabolic and dietary oxidized free radicals and AGEs. Antioxidants in fruit can protect beta cells. Researchers have found that eating <a href="https://www.bmj.com/content/347/bmj.f5001">whole fruit decreases the risk of Type 2 diabetes</a>, with those who <a href="https://doi.org/10.1210/clinem/dgab335">eat the most fruit having the lowest risk</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="hands pouring sugar into a bowl with strawberries in the background" src="https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/440475/original/file-20220112-19-1uy72hg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As you consume less refined sugar, you may notice more nuance in fruits’ flavors.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/christine-burns-rudalevige-pours-sugar-into-the-strawberry-news-photo/806582004">Brianna Soukup/Portland Portland Press Herald via Getty Images</a></span>
</figcaption>
</figure>
<h2>Detoxing from sugar</h2>
<p>People interested in losing weight and improving health often ask if they should do a “sugar detox.” In my opinion this is a waste of time, because it is not possible to eliminate sugar from the body. For instance, if you ate only baked chicken breasts, your liver would convert protein to glucose in a process called <a href="https://www.ncbi.nlm.nih.gov/books/NBK541119/">gluconeogenesis</a>.</p>
<p>Low-carb diets may lead to weight loss, but at the expense of health. Diets that significantly reduce carbohydrates are associated with <a href="https://doi.org/10.1186/1550-2783-7-24">nutrient deficiencies</a> and higher <a href="https://doi.org/10.1371/journal.pone.0055030">risk of death from any cause</a>. On low-carbohydrate <a href="https://www.ncbi.nlm.nih.gov/books/NBK499830/">ketogenic</a> diets the <a href="https://doi.org/10.3390/nu13020374">body will break down muscles</a> and turn their protein into glucose. The lack of fiber causes constipation.</p>
<p>Eliminating foods sweetened with refined sugar is a worthy goal. But don’t think of it as a “detox” – it should be a permanent lifestyle change. The safest way to go on a refined sugar “detox” is to increase your intake of nutrient-dense fruits and vegetables. Once you eliminate refined sugar, you’ll likely find that your taste buds become more sensitive to – and appreciative of – the natural sweetness of fruits.</p>
<p></p><hr> <p></p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/439239/original/file-20220103-48418-1p7tcpi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>This article is part of a series examining sugar’s effects on human health and culture. <a href="https://theconversation.com/us/topics/sugar-2022-114641">You can read the articles on theconversation.com.</a></em></p><img src="https://counter.theconversation.com/content/173992/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jennifer Rooke works for Morehouse School of Medicine. This is stated in the article.</span></em></p>
Sugar gets a bad rap, but exactly which sugar is meant? Nutrient-dense sweet ripe fruits are a far cry from refined table sugar – and their differences can have big health implications.
Jennifer Rooke, Assistant Professor of Community Health & Preventive Medicine, Morehouse School of Medicine
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/156900
2021-12-27T12:58:46Z
2021-12-27T12:58:46Z
Not all calories are equal – a dietitian explains the different ways the kinds of foods you eat matter to your body
<figure><img src="https://images.theconversation.com/files/438740/original/file-20211221-27-qlzv07.jpg?ixlib=rb-1.1.0&rect=0%2C405%2C4431%2C3320&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Even if two foods share the same calorie count, there can be major differences in how they affect your body.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/healthy-and-unhealthy-food-background-from-fruits-royalty-free-image/1249589196">Julia_Sudnitskaya/iStock via Getty Images</a></span></figcaption></figure><p>A calorie is a calorie is a calorie, at least from a thermodynamic standpoint. It’s defined as the amount of energy needed to raise the temperature of 1 kilogram of water by 1 degree Celsius (2.2 pounds by 1.8 degrees Fahrenheit).</p>
<p>But when it comes to health and your body’s energy balance, not all calories are equal.</p>
<p>For example, <a href="https://doi.org/10.1056/NEJMoa022207">some studies have reported</a> that <a href="https://doi.org/10.1186/1743-7075-11-53">diets that are</a> <a href="https://doi.org/10.1038/sj.ijo.0800867">high-protein</a>, <a href="https://doi.org/10.1210/jc.2002-021480">low-carbohydrate</a> or a combination of the two do <a href="https://doi.org/10.1056/NEJMoa022637">yield greater weight loss</a> than diets with other levels of fat, protein and carbs.</p>
<p>If every calorie in food were the same, you wouldn’t expect to see weight-loss differences among people who eat the same number of calories that are doled out in different types of food.</p>
<p><a href="https://scholar.google.com/citations?user=nrjfStkAAAAJ&hl=en&oi=ao">Dietitians like me</a> know there are many factors that influence what a calorie means for your body. Here’s what we understand about calories and nutrition so far.</p>
<h2>Energy actually available to your body</h2>
<p>In the late 1800s, chemist W.O. Atwater and his colleagues devised a system to figure out how much energy – that is, how many calories – various foods contain. Basically, he burned up food samples and recorded how much energy they released in the form of heat.</p>
<p>Not every bit of energy in food that can combust in the lab is actually available to your body, though. What scientists call <a href="https://doi.org/10.1093/jn/124.suppl_9.1738S">metabolizable energy</a> is the difference between the total energy of the food consumed and the energy that passes out of your body, undigested, in feces and urine. For each of the three macronutrients – proteins, carbohydrates and fats – Atwater devised a percentage of the calories they contained that would actually be metabolizable.</p>
<p><iframe id="ncG8V" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/ncG8V/5/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>According to the Atwater system, one gram of each macronutrient is estimated to provide a certain number of calories. The U.S. Department of Agriculture still uses these calculations today to come up with an <a href="https://fdc.nal.usda.gov/">official calorie number</a> for every food.</p>
<h2>How much energy you use</h2>
<p>What you eat can affect what scientists call your body’s <a href="https://doi.org/10.1007/978-1-4419-1005-9_454">energy expenditure</a>. That’s how much energy it takes to keep you alive – energy you use breathing, digesting, keeping your blood flowing and so on – along with what you exert moving your body. You might have heard this <a href="https://theconversation.com/whether-slow-or-fast-heres-how-your-metabolism-influences-how-many-calories-you-burn-each-day-149231">referred to as metabolism</a>.</p>
<p>Diet quality can alter the body’s energy expenditure, which is also called the <a href="https://doi.org/10.1172/JCI112913">thermic effect of food</a>. For example, in one study, people eating the same number of calories per day but on either a low-carbohydrate diet or a low-fat diet had <a href="https://doi.org/10.1001/jama.2012.6607">differences in total energy expenditure</a> of about 300 calories per day. Those eating very low-carb diets used the most energy, while those eating low-fat diets used the least.</p>
<p>In another study, <a href="https://doi.org/10.1002/j.1550-8528.1994.tb00074.x">high-fat diets led to lower</a> total energy expenditure than high-carb diets did. Other researchers reported that although substituting carbs for fat did not alter energy expenditure, people who increased their protein intake to 30%-35% of their diet <a href="https://doi.org/10.1093/ajcn/79.5.899S">used more energy</a>.</p>
<p>In general, diets high in carbohydrates, <a href="https://doi.org/10.1038/sj.ijo.0800810">fat or both produce a 4%-8% increase</a> in energy expenditure, while meals <a href="https://doi.org/10.1038/sj.ejcn.1600578">high in protein cause an 11%-14% increase</a> above the resting metabolic rate. Protein has a higher thermic effect because it’s harder for the body to break down. Although these variations aren’t huge, they could <a href="https://doi.org/10.17925/EE.2013.09.02.111">contribute to the obesity epidemic</a> by encouraging a subtle average weight gain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Nutrition Facts panels from multiple food packages" src="https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/438736/original/file-20211221-25-1qkrnq3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Nutrition Facts food labels contain much more than just calorie counts – for good reason.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/nutrition-label-giving-information-on-good-food-royalty-free-image/185262405">Imagesbybarbara/E+ via Getty Images</a></span>
</figcaption>
</figure>
<h2>Quality of the calories you eat</h2>
<p>Dietitians pay attention to a <a href="https://doi.org/10.1001/jama.287.18.2414">food’s glycemic index</a> and <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/glycemic-load">glycemic load</a> – that is, how quickly and how much it will increase your blood glucose levels. A rise in blood glucose triggers the release of insulin, which in turn influences energy metabolism and storage of excess energy as fat.</p>
<p>Foods like white rice, cakes, cookies and chips are all high on the glycemic index/load. Green vegetables, raw peppers, mushrooms and legumes are all low on the glycemic index/load. There is some evidence to suggest that foods <a href="https://doi.org/10.1016/j.numecd.2013.04.008">lower on the glycemic index/load</a> may be <a href="https://doi.org/10.1001/jama.287.18.2414">better for keeping blood sugar levels regulated</a> – regardless of the calories they contain.</p>
<p>Reward centers in the brain light up when people eat high glycemic index/load foods, highlighting the <a href="https://doi.org/10.3945/ajcn.113.064113">pleasurable and addictive effect</a> of foods like candy or white breads.</p>
<p><a href="https://doi.org/10.1371/journal.pmed.1003053">The fiber content of food</a> is another thing to consider. Your body can’t digest fiber – found in plant foods like fruits, vegetables, whole grains and beans – for energy. So foods high in fiber tend to have <a href="https://doi.org/10.3945/ajcn.117.163246">less metabolizable energy</a> and can help you feel full on fewer calories.</p>
<p>Empty calories – those from foods with minimal or no nutritional value – are another factor to consider. Things like white sugar, soft drinks and many ultra-processed snacks don’t provide much, if any, benefit in the form of protein, vitamins or minerals along with their calories. The opposite would be <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/nutrient-dense-food">nutrient-dense foods</a> that are high in nutrients or fiber, while still being relatively low in calories. Examples are spinach, apples and beans.</p>
<p>And don’t think of empty calories as neutral. Nutritionists consider them harmful calories because they can have a negative effect on health. <a href="https://doi.org/10.1056/NEJMoa1014296">Foods that are the biggest contributors to weight gain</a> are potato chips, potatoes, sugar-sweetened beverages and meats, both processed and unprocessed. On the other hand, foods that are inversely associated with weight gain are vegetables, whole grains, fruits, nuts and yogurt.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="view from above of plates on a table where people are eating" src="https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/438737/original/file-20211221-27-1rjoeti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Food provides more than calories.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/friends-eating-together-royalty-free-image/658616918">Ridofranz/iStock via Getty Images</a></span>
</figcaption>
</figure>
<h2>More to health than calories and weight</h2>
<p>It is indisputable that for weight loss, the difference between the number of calories consumed and the number of calories exerted through exercise is the most important factor. But don’t fool yourself. While weight plays a role in health and longevity, weight loss alone doesn’t equate to health.</p>
<p>Yes, some high-protein diets seem to promote weight loss at least in the short term. But epidemiologists know that in areas where people live the longest – close to 100 years on average – they <a href="https://doi.org/10.1093/jn/131.11.3065S">eat a primarily plant-based diet</a>, with very low or no animal-based protein and low or moderate fat in the form of mono- and polyunsaturated fats.</p>
<p>I often hear friends or clients say things like “it’s those carbs that are making me fat” or “I need to go on a low-carb diet.” But these complaints drive dietitians like me, well, nuts. Carbohydrates include foods like Coca-Cola and candy canes, but also apples and spinach. Cutting down on simple carbs like soft drinks, refined-flour bakery items, pasta and sweets will definitely have a positive impact on health. But eliminating carbohydrates like vegetables and fruit will have the opposite effect.</p>
<p><a href="https://doi.org/10.1016/j.ebiom.2019.04.005">A plant-based diet</a> <a href="https://doi.org/10.1136/bmj.m2412">high in plant-based protein</a> <a href="https://doi.org/10.1016/j.cell.2015.02.020">and carbohydrates</a> mostly from vegetables, fruit, nuts and legumes is <a href="https://doi.org/10.1079/phn2004558">the healthiest diet researchers know of</a> for longevity and prevention of chronic diseases like heart disease, cancer, hypertension and many other conditions. </p>
<p>The modern Western diet suffers from an <a href="https://doi.org/10.1038/ijo.2012.225">increase in quantity of calories</a> consumed with a concurrent <a href="https://doi.org/10.3945/ajcn.114.100867">decrease in the quality of calories</a> consumed. And researchers now know that calories from different foods <a href="https://doi.org/10.1056/NEJMoa1014296">have different effects</a> on fullness, insulin response, the process of turning carbs to body fat, and metabolic energy expenditure.</p>
<p>Where your health is concerned, count more on the quality of the calories you consume than the calorie count.</p>
<p>[<em>Get the best of The Conversation, every weekend.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybest">Sign up for our weekly newsletter</a>.]</p><img src="https://counter.theconversation.com/content/156900/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Terezie Tolar-Peterson does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
In almost every way, one cheeseburger does not equal six apples. With the goal of optimal health in mind, a calorie is not a calorie is not a calorie.
Terezie Tolar-Peterson, Associate Professor of Food Science, Nutrition & Health Promotion, Mississippi State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/153425
2021-01-29T05:05:47Z
2021-01-29T05:05:47Z
Planning on running a marathon? A sports dietitian on what to eat for long-distance running
<figure><img src="https://images.theconversation.com/files/380799/original/file-20210127-17-if809z.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5000%2C3330&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Did you make a New Year’s resolution to run a marathon? Or perhaps you’ve conquered a marathon and want to take on an even longer event?</p>
<p>Your diet is crucial in long-distance running. If you don’t eat the right foods in the right amounts, you might not get enough energy to train and compete properly.</p>
<p>Over time, not having enough energy during training can lead to “relative energy deficiency in sport” (RED-S) syndrome. This condition can cause problems <a href="https://pubmed.ncbi.nlm.nih.gov/29773536/">such as</a> poor recovery between training sessions, reduced training capacity, recurring injuries, and a suppressed immune system.</p>
<p>It can also put you at risk of <a href="https://pubmed.ncbi.nlm.nih.gov/29773536/">further health complications</a>. The major long-term one is an increased risk of osteoporosis and bone fractures. Depending on the severity, it can also cause heart problems and gastrointestinal issues such as constipation.</p>
<p>To lower your risk of relative energy deficiency, here’s what you should eat if you’re running long distances.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1054380043437260800"}"></div></p>
<h2>Carbs are your best friend</h2>
<p>Carbohydrates provide most of the energy used during any length of exercise.</p>
<p>The <a href="https://www.tandfonline.com/doi/full/10.1080/02640414.2011.585473">International Olympic Committee on Nutrition for Sport</a> recommends endurance athletes, who compete or train up to three hours a day, consume at least 6-10 grams of carbs per kilogram of body weight each day.</p>
<p>For a 70kg person, this equates to 420-700g a day. For ultra-endurance athletes (people who train or compete for more than four or five hours per day) it’s 8-12g per kilogram. For a 70kg athlete, that’s 560-840g a day. </p>
<p>About 50g of carbs can be found in each of the following foods: five Weetbix biscuits, four slices of bread, two large bananas, three medium-sized potatoes, 600ml flavoured milk, a cup of rice, or one-and-a-third cups of pasta. As you can see, you would have to eat quite a lot of carbs throughout the day to reach the recommendation! </p>
<figure class="align-center ">
<img alt="Person eating pasta" src="https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/380801/original/file-20210127-15-1yklkxu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Eating plenty of carbohydrates is critical for giving your body enough energy to run long distances.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The committee also <a href="https://www.tandfonline.com/doi/full/10.1080/02640414.2011.585473">recommends</a> you eat 1-4g of carbs per kilogram of body weight in the four hours before exercise.</p>
<p>So for a 70kg runner, that means 70-280g of carbs before an event. There’s roughly 70g of carbs in each of the following: two slices of fruit toast with a large banana, one-and-a-half cups of cooked pasta, or 600mls of flavoured milk plus an apple.</p>
<p>You also need to keep up your carb intake during endurance events. You’ll need to consume 30-60g per hour, and during ultra-endurance events up to 90g per hour, regardless of your weight. Ideally, the <a href="https://www.sportsdietitians.com.au/factsheets/fuelling-recovery/eating-drinking-exercise/">foods would be high in carbohydrates and low in fibre</a> to minimise gastrointestinal discomfort such as bloating or runner’s diarrhoea.</p>
<p>A total of 60g of carbs would be three slices of white bread with jam, or two energy gels (small packets of high-carbohydrate gel). Sports drinks are also useful if you don’t feel like eating. A 600ml bottle would help with rehydration and provide about 40g of carbs.</p>
<p><iframe id="BPazl" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/BPazl/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>These recommendations are only guides. Athletes should consider their current diet along with training intensity, whether they’re meeting training goals, how quickly they tire during training or competition, recovery between training sessions, and weight changes.</p>
<figure class="align-center ">
<img alt="Runner consuming an energy gel" src="https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381040/original/file-20210128-23-k8w1qq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">If you’re running a marathon, make sure you have 30-60 grams of carbs every hour, which you could find in two energy gels.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Also consider fat and protein</h2>
<p>More fat is used as the duration of exercise increases, and if the exercise lasts more than four hours, your body will begin to use small amounts of protein. It’s hard to determine the exact levels of fat and protein used, as this depends on the intensity of exercise and level of training.</p>
<p>Nevertheless, as fat contributes to energy, it’s important to include healthy fat sources such as olive oil, nuts, seeds and dairy products in your diet, although there are no set guidelines for how much fat you need to eat. </p>
<p>There’s also some evidence omega-3 fats, found in fish, may support <a href="https://pubmed.ncbi.nlm.nih.gov/21501117/">muscle growth</a> and <a href="https://www.tandfonline.com/doi/full/10.1080/17461391.2018.1491626">reduce muscle soreness</a>.</p>
<p>Protein is needed for muscle repair. The <a href="https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0177-8?_ga=2.12383604.1190971563.1580748342-1020357470.1573142582">International Society of Sports Nutrition Guidelines</a> recommend endurance athletes consume 1.4g of protein per kilogram of body weight, every day. This equates to 98g for a 70kg runner. Each of these foods contains about 10g of protein: two small eggs, 30g cheese, 40g lean chicken, 250ml dairy milk, three-quarters of a cup of lentils, 120g tofu, 60g nuts or 300ml soy milk.</p>
<p>Consuming 20g of protein in the 1-2 hours after exercise <a href="https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0177-8?_ga=2.12383604.1190971563.1580748342-1020357470.1573142582">helps maximise</a> muscle repair and gain. This amount of protein can be found in one small tin of tuna, 600ml of milk, or 80g of chicken.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/science-of-champion-runners-inside-the-body-of-elite-endurance-athletes-146639">Science of champion runners: inside the body of elite endurance athletes</a>
</strong>
</em>
</p>
<hr>
<h2>Drink plenty of water (but don’t go overboard)</h2>
<p>You can lose a significant amount of water via sweat during endurance training and events. Making sure you’re hydrated is vital for performance and health. One of the easiest ways to know how hydrated you are is by checking your urine colour — it should be clear or hay-coloured. If it’s amber or darker, you need to drink more water.</p>
<p>While dehydration is problematic, you should also be careful not to drink extreme amounts of water, which can cause sodium levels to drop too low. This is rare, but if you gain weight right after an long-distance event, it might mean you’re drinking too much water.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/too-much-of-a-good-thing-how-drinking-too-much-water-can-kill-9700">Too much of a good thing? How drinking too much water can kill</a>
</strong>
</em>
</p>
<hr>
<h2>And don’t forget iron</h2>
<p>One of the most important nutrients for endurance athletes is iron. Iron loss occurs during heavy sweating, and women are at increased risk of iron deficiency with menstrual losses.</p>
<p>It’s important to include red meat in your diet, or if vegetarian or vegan to consume more beans, lentils and whole grains.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-get-the-nutrients-you-need-without-eating-as-much-red-meat-110274">How to get the nutrients you need without eating as much red meat</a>
</strong>
</em>
</p>
<hr>
<p>Ultimately, no two athletes have the same requirements to achieve the goals they want from training and competing.</p>
<p>While you may be tempted to buy supplements to improve your performance, this will have little impact unless you get the diet right first. It may be worthwhile talking to an accredited sports dietitian to ensure you’re meeting your energy and fluid requirements and are not at risk of relative energy deficiency syndrome.</p><img src="https://counter.theconversation.com/content/153425/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Evangeline Mantzioris has previously worked in private practice as an accredited sports dietitian.</span></em></p>
We asked an accredited sports dietitian to describe what you need in your diet if you’re running long distances.
Evangeline Mantzioris, Program Director of Nutrition and Food Sciences, University of South Australia
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/153251
2021-01-15T10:12:35Z
2021-01-15T10:12:35Z
Type 2 diabetes: short-term low-carb diet linked to remission – but only if weight is lost
<figure><img src="https://images.theconversation.com/files/378833/original/file-20210114-21-1b7lte0.jpg?ixlib=rb-1.1.0&rect=13%2C0%2C4579%2C3064&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Were low-carb diets really better at achieving remission?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/diet-concept-healthy-lifestyle-low-calorie-719049571">Flotsam/ Shutterstock</a></span></figcaption></figure><p>Whether restricting carbohydrate intake is an effective way to manage type 2 diabetes is a topic of some controversy in nutrition – largely because trial results have so far been pretty inconclusive. While <a href="https://www.sciencedirect.com/science/article/pii/S0168822717304023">multiple meta-analyses</a> have reviewed the current body of research and found low-carbohydrate diets are able to lower blood glucose in the short-term, such diets don’t appear to be any better than higher carbohydrate diets in managing blood sugar levels <a href="https://pubmed.ncbi.nlm.nih.gov/26446553/">in the long term</a>.</p>
<p>Now, a <a href="https://www.bmj.com/content/372/bmj.m4743">new meta-analysis</a> (which combines the results of multiple scientific studies on a given topic) has looked at the use of low-carbohydrate diets in achieving type 2 diabetes remission. <a href="https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/treating-your-diabetes/type2-diabetes-remission">Remission</a> means a person who has previously been diagnosed with type 2 diabetes now has blood glucose in the non-diabetic range. </p>
<p>In general, their findings mirror what other meta-analyses have found, showing that low-carbohydrate diets are somewhat better than other diets at achieving remission when followed for a period of six months. However, these benefits largely disappeared at 12 months. They also found that whether a person achieved remission depended largely on whether they lost weight while following a low-carb diet.</p>
<p>The researchers looked at 23 studies, which included 1,327 people with type 2 diabetes altogether. The type of low-carbohydrate diet participants followed varied between studies. Some were very low-calorie weight loss diets, while others didn’t restrict calories at all. The amount of carbohydrates participants could eat ranged depending on the study, from 20g to 130g per day. </p>
<p>How long participants followed the diet also varied between studies, with some following a low-carb plan for eight weeks, others for two years. The control diets also varied between studies. Some were intensive weight loss interventions, others higher-carb, while in others the control group was given weight loss advice with no ongoing support.</p>
<p>It’s also worth noting there’s currently no agreed <a href="https://abcd.care/sites/abcd.care/files/resources/ABCD-and-PCDS-final-statement-3March2019.pdf">definition of remission</a>. So in this meta-analysis, the researchers considered remission to have been achieved if a person’s blood glucose level was under the threshold used to diagnose type 2 diabetes. This was regardless of whether a person was still taking medications that lower glucose. </p>
<p>This is important to know, as this meta-analysis showed low-carbohydrate diets were only significantly better than the control diets at achieving remission when they continued using medication to lower their blood glucose. Without the use of medication, low-carbohydrate diets were no longer superior to others in achieving remission.</p>
<h2>Weight loss</h2>
<p>The meta-analysis showed that weight loss was a major factor in whether a study showed greater remission with a low-carb diet or not. For example <a href="https://dom-pubs.onlinelibrary.wiley.com/doi/full/10.1111/dom.13915">two</a> <a href="https://www.nature.com/articles/s41387-017-0006-9">studies</a> included in the meta-analysis showed much greater remission in the low-carbohydrate group compared to the control. </p>
<p>But this remission was likely because the low-carb diets were also lower in calories, resulting in greater weight loss. For example, one study had the low-carb group eat only 800 calories per day, while the control group was only given dietary advice without ongoing support. In both cases, the low-carb group lost a greater amount of weight, making the relative chance of achieving remission from a low-carbohydrate diet in these two studies appear very high.</p>
<p>But if the control group lost as much weight as the low-carbohydrate group, the likelihood of achieving remission with a low-carbohydrate diet appeared lower. As <a href="https://pubmed.ncbi.nlm.nih.gov/25071075/">one study</a> included in the meta-analysis showed, 36 out of 46 people on a low-carbohydrate diet achieved remission. However, the control group who followed a high-carbohydrate diet with the same calorie restriction achieved remission in 30 out of 47 people. Both groups lost about 12kg on average, so remission was high overall.</p>
<p>The authors acknowledge weight is the primary driver of remission in the studies they looked at. While low-carbohydrate groups lost more weight on average compared to the control groups (around 7.4kg), this weight difference disappeared by 12 months, with remission following a similar pattern.</p>
<figure class="align-center ">
<img alt="An assortment of healthy foods, including salmon, berries, cheese, and legumes." src="https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378838/original/file-20210114-21-7qcra1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Protein intake also wasn’t controlled, which could have impacted the results.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/balanced-diet-food-background-1149431816">nadianb/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Another issue in knowing whether low-carbohydrate diets are useful in treating diabetes is that in many studies, the amount of carbs people consumed on a low-carb diet varied. This could impact whether some low-carb diets worked better than others. Similarly, none of the studies controlled protein intake. Protein <a href="https://pubmed.ncbi.nlm.nih.gov/12610012/">promotes insulin secretion from the pancreas</a> and can lower blood glucose <a href="https://pubmed.ncbi.nlm.nih.gov/14522731/">independent of weight loss</a>. Many of the low-carb diets <a href="https://pubmed.ncbi.nlm.nih.gov/22562179/">doubled the calories from protein</a>, which could also have impacted chance of remission.</p>
<p>None of the studies in the meta-analysis controlled for medication use or changes in medication. This makes it difficult to really see whether a low-carb diet would have reduced blood sugar levels if medications to manage blood sugar weren’t being taken. Indeed, studies that have measured the use of glucose-lowering medications while following a diet have shown that people <a href="https://care.diabetesjournals.org/content/37/11/2909.long">reduce their medication use more</a> with low-carbohydrate diets compared to high-carb ones.</p>
<p>This meta-analysis highlights the importance of weight loss in improving blood sugar levels – and potentially achieving remission from type 2 diabetes. However, low-carbohydrate diets do seem to be very useful at achieving greater weight loss in the short term.</p><img src="https://counter.theconversation.com/content/153251/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicola Guess consults to Diet Doctor.
I have received grant funding to look at low-carbohydrate high-protein diets. </span></em></p>
Latest meta-analysis shows weight loss is the most important factor in achieving remission.
Nicola Guess, Lecturer, King's College London
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/138662
2020-05-26T12:54:15Z
2020-05-26T12:54:15Z
‘Fat burning zone’? The best way to exercise to burn fat
<figure><img src="https://images.theconversation.com/files/337595/original/file-20200526-106832-2u2yv.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C6313%2C4268&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Exercises like jogging require less energy from our body – so energy comes predominantly from fats.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/group-healthy-people-jogging-city-park-1123484066">dotshock/ Shutterstock</a></span></figcaption></figure><p>When it comes to losing weight, people often want know the best way to shed excess pounds – and there’s no shortage of fad diets or fitness crazes claiming to have the “secret” to fat loss. One theory even suggests that exercising at around 60% of your maximum heart rate will bring our bodies into a so-called “fat burning zone”, optimal for losing weight.</p>
<p>But does this “fat burning zone” even exist?</p>
<p>First, it’s important to understand a little about our metabolism. Even if we were to sit at our desk all day, our body still needs “fuel” to <a href="https://www.sciencedirect.com/science/article/abs/pii/S1751499111000060">meet energy demands</a>. This energy comes from carbohydrates, proteins, fats and phosphates. However, the rate at which we use them, and how much we have available, varies between people. It depends on a <a href="https://www.sciencedirect.com/science/article/abs/pii/S1751499111000060">number of factors</a>, such as dietary intake, age, sex and how hard or often we exercise.</p>
<p>Generally, exercising at lower intensities – such as sustained walking or light jogging – doesn’t require as much effort by our muscles as sprinting, for example. This means the amount of energy needed by the body is lower, so energy supply predominantly comes from fats.</p>
<p>But as exercise intensity increases, fat can’t be metabolised fast enough to meet increased energy demand. So the body will use carbohydrates, as these can be metabolised more rapidly. This means there is indeed an exercise intensity where fat is the predominant energy source.</p>
<p>At the lower end of this spectrum is our resting state. Here, the number of calories our body needs to function is considerably low, so the body primarily metabolises fat to use for energy. This means the potential “zone” for metabolising fat is between the rested state and the level of exercise intensity where carbohydrates become the dominant energy source (in terms of percent contribution to energy demand).</p>
<p>But this is a wide range, which lies between a resting heart rate of around 70 beats per minute to around 160 beats per minute during moderate effort exercise (such as cycling at a constant speed where holding a conversation becomes challenging), where the crossover from using fat to carbohydrates for energy occurs.</p>
<p>The issue with such a wide zone is that the person exercising wouldn’t necessarily be optimising their ability to metabolise fat, because as the exercise intensity increases there’s a gradual change in the balance of fat and carbohydrates your body uses for energy. </p>
<h2>Fat burning zone</h2>
<p>So how can we know at which point our body will switch from using fat to other fuels for energy? One approach researchers take is <a href="https://www.ncbi.nlm.nih.gov/pubmed/29875697">assessing how much fat</a> is being used for energy during different exercise intensities.</p>
<p>By measuring how much air a person expels during an exercise test which gets progressively harder, physiologists have been able to calculate the relative contributions of fat and carbohydrates to meet the exercise demand at different intensities. The highest amount of fat burned is called the “maximal fat oxidation rate” (or MFO), and the intensity this occurs at is termed “FATmax”.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/337600/original/file-20200526-106811-w03f8k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The more intense the exercise, the less fat our body draws upon for energy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-doing-hiit-workout-on-stairs-653313538">baranq/ Shutterstock</a></span>
</figcaption>
</figure>
<p>Since this method was <a href="https://www.ncbi.nlm.nih.gov/pubmed/11782653">first used by researchers</a>, studies have shown that as the intensity rises from around 40-70% of a person’s VO₂ max – which is the maximum amount of oxygen a person can use during exercise – there’s an increase in the rate of carbohydrates and fats being used. The rate of fat being burned starts to decline at higher intensities as the body requires energy more rapidly.</p>
<p>The so-called “fat burning zone” has been shown to occur anywhere between about <a href="https://www.ncbi.nlm.nih.gov/pubmed/11782653">50-72% of a person’s VO₂ max</a>. However, the ability to burn fat is also based on genetics, with studies showing that this fat burning zone is likely to be lower in overweight or obese people – <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683615/">around 24-46%</a> of their VO₂ max – and higher in <a href="https://www.ncbi.nlm.nih.gov/pubmed/12800102">endurance athletes</a>.</p>
<p>Another point to consider is how much fat we actually burn during exercise (if we express it in grams per minute). The answer is: surprisingly little. Even in studies with athletes, at FATmax, participants only burned on average a mere <a href="https://www.ncbi.nlm.nih.gov/pubmed/11782653">0.5 grams of fat</a> per minute. This would equate to around 30 grams of fat per hour. </p>
<p>In the average person, this appears to be even lower, ranging between <a href="https://www.ncbi.nlm.nih.gov/pubmed/29564847">0.1 and 0.4 grams of fat</a> per minute. To put it in perspective, one pound of fat <a href="https://www.healthline.com/nutrition/calories-in-a-pound-of-fat#section2">weighs around 454 grams</a>. So, though training in this fat burning zone will help with fat loss, this might also help explain why it takes some people longer to lose fat through exercise. </p>
<p>But there is evidence that <a href="https://www.ncbi.nlm.nih.gov/pubmed/15212756">following certain diets</a> (such as intermittent fasting or a <a href="https://www.ncbi.nlm.nih.gov/pubmed/30953522">ketogenic, high fat diet</a>) and longer exercise can increase the actual <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5766985/">amount of fat we burn</a>. </p>
<p>Perhaps it’s time to no longer consider “burning fat” to have a “zone”, but rather an individualised “sweet spot” which can be used to optimise our exercise regimes to lose weight. Regular physical activity around this “sweet spot” (which typically occurs at a low to moderate feeling of effort, for example 30-60% of your maximal effort, or a perceived exertion level of one to four out of ten) will likely improve our body’s efficiency in using fat for energy – and translate to a lower overall body fat percentage.</p>
<hr>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=140&fit=crop&dpr=1 600w, https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=140&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=140&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=176&fit=crop&dpr=1 754w, https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=176&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/301912/original/file-20191115-66957-gxdqkd.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=176&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em>Get the latest news and analysis, direct from the experts in your inbox, every day. Join hundreds of thousands who trust experts by <strong><a href="http://theconversation.com/newsletter?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCNewsletter&utm_content=newsletterA">subscribing to our newsletter</a></strong>.</em></p><img src="https://counter.theconversation.com/content/138662/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Though exercising at around 50-72% of our VO₂ uses more fat as energy, the amount of actual fat burned is minimal.
Justin Roberts, Principal Lecturer, Anglia Ruskin University
Ash Willmott, Lecturer in Sport and Exercise Science, Anglia Ruskin University
Dan Gordon, Principal Lecturer Sport and Exercise Sciences, Anglia Ruskin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/129629
2020-01-15T14:08:14Z
2020-01-15T14:08:14Z
How we deduced that our ancestors liked roast vegetables too
<figure><img src="https://images.theconversation.com/files/309461/original/file-20200110-97145-fxrle.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The rhizomes of this flowering plant, Hypoxis angustifolia, were cooked by early humans.</span> <span class="attribution"><span class="source">© Lyn Wadley</span></span></figcaption></figure><p>Archaeological work at the <a href="https://www.tandfonline.com/doi/full/10.1080/00934690.2018.1504544">Border Cave site</a> has revealed the earliest evidence for cooked root vegetables. Border Cave lies between South Africa and <a href="https://www.bbc.com/news/world-africa-43821512">eSwatini</a> and has a remarkable record of human habitation. </p>
<p>Hot, roasted root vegetables are comfort food, and a plateful of <a href="https://www.hsph.harvard.edu/nutritionsource/carbohydrates/">carbohydrate</a> is both satisfying and nutritious. Archaeologists have found that our ancestors thought so, too. A team working at the site has <a href="https://www.sciencedaily.com/releases/2020/01/200102143424.htm">discovered and documented</a> the remains of starchy underground plant stems (called rhizomes) cooked 170,000 years ago. </p>
<p>Border Cave’s roasted rhizomes were identified as <a href="http://pza.sanbi.org/hypoxis"><em>Hypoxis angustifolia</em></a> (yellow stars). This was done by comparing their shape and internal anatomy to those of modern rhizomes which today grow in countries along the eastern flank of Africa. The distribution extends much further too, for example into Yemen. </p>
<p>If, as seems likely, <em>Hypoxis</em> had a similar distribution in the past, it would have provided a secure staple food for people travelling within and out of Africa.</p>
<p>Our findings suggest that the food was transported to the cave and then cooked. The food could easily have been consumed directly in the field by the collectors, but our findings suggest this wasn’t the case, adding extra information about social behaviour and sharing – and a glimpse into ancient communal behaviour – 170,000 years ago. Food was the focus for satisfying physical and social hunger.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309452/original/file-20200110-97140-1ynour.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A drone image of Border Cave, a rich source of knowledge about the past because of well documented human habitation in the cave.</span>
<span class="attribution"><span class="source">© Ashley Kruger</span></span>
</figcaption>
</figure>
<h2>Eating habits of our ancestors</h2>
<p><em>Hypoxis angustifolia</em> plants are gregarious so many can be harvested at once. Wooden digging sticks or sharpened bones may have been used to dig rhizomes from the ground. </p>
<p>The food was carried home to the cave, perhaps as a hide-wrapped parcel or a simple bunch tied with leaves. </p>
<p>Wood was also collected for the cooking fire that probably burned to small coals and hot ash before the rhizomes were added directly to the ashes for roasting. Some South Africans are familiar with this cooking technique: as children we made <a href="https://anthrochef.blog/2017/08/11/ash-bread/">“askoek” (ash cakes)</a> directly on coals and tapped them on rocks to dislodge the ash before garnishing our culinary treasures with apricot jam. </p>
<p>Some of the thumb-sized Border Cave rhizomes were lost in the ashes where they were burned and thus preserved for archaeologists. We know that they were burned while still fresh and “green” because the charred rhizomes have split surfaces. This was caused by shrinkage when moisture was rapidly expelled. Many starchy root vegetables can be eaten raw, but their nutritional content is much greater when cooked (the human gut can then access the glucose better and absorb much more of it). </p>
<p>Cooking made <em>Hypoxis</em> rhizomes easy to peel, and rendered them digestible by releasing glucose and breaking down the fibre. Such treatment was particularly important for the aged members of the group and small children that might otherwise have had difficulty chewing the rhizomes. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309460/original/file-20200110-97158-11crlf5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some Border Cave <em>Hypoxis</em> rhizomes. Each rhizome is about 1.2cm wide. Top left is a diagram of the internal structure of <em>Hypoxis</em>, showing splits in the charcoal, mucilage cavities in black, and white ovals representing xylem bundles. On the right is a bundle of xylem vessels magnified 2,000 times.</span>
<span class="attribution"><span class="source">Lyn Wadley</span></span>
</figcaption>
</figure>
<p>The Border Cave occupants were modern humans (<a href="http://humanorigins.si.edu/evidence/human-fossils/species/homo-sapiens"><em>Homo sapiens</em></a>) with the same nutritional needs as people today. To enable our large brains to function we need to consume about 100g of <a href="https://www.dietdoctor.com/low-carb/does-the-brain-need-carbs">carbohydrate per day</a>. <em>Hypoxis</em> rhizomes may have fulfilled that need in the past. </p>
<p>We know, too, that Border Cave dwellers also ate meat because we have recovered the cooked bones of wild animals that were eaten in the cave. In Africa, game meat is lean, especially in the dry season when animals lose weight. Lean meat protein cannot be metabolised by humans in the absence of either carbohydrates or fat. </p>
<p>The addition of some carbohydrate to their diet would then have enabled early humans to process protein effectively. A balanced, healthy diet with a combination of cooked carbohydrate and protein – the “real” palaeo-diet - increased human fitness and longevity.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=423&fit=crop&dpr=1 754w, https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=423&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/309451/original/file-20200110-97126-1cpn7uc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=423&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The excavation work underway at Border Cave.</span>
<span class="attribution"><span class="source">© Lucinda Backwell</span></span>
</figcaption>
</figure>
<h2>The discovery</h2>
<p>We discovered the first of the rhizomes in 2016 while digging in Border Cave’s ashy sediments. The sediments date between 170,000 and 100,000 years ago. </p>
<p>In total, 55 whole charred rhizomes were recovered, all from the same species. We worked together in the field over a period of four years, collecting modern plants with rhizomes so that we could compare these with the Border Cave ones in order to identify them. </p>
<p>With a permit from local wildlife authorities, we surveyed the Lebombo Mountain hillside near the cave for interesting plants with appropriate rhizomes. When a plant could not immediately be identified it was planted in a vegetable garden to await flowering. When each plant was securely identified, its rhizome was charred, examined microscopically, and compared with Border Cave specimens. </p>
<p>Eventually patience was rewarded, and a combination of morphological and anatomical evidence showed that the Border Cave rhizome was a <em>Hypoxis</em>.</p><img src="https://counter.theconversation.com/content/129629/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lyn Wadley received funding from the Centre of Excellence, University of the Witwatersrand.</span></em></p><p class="fine-print"><em><span>Christine Sievers has received funding from the National Research Foundation</span></em></p>
The charred remains of root vegetables found at Border Cave help us understand how early humans survived and thrived.
Lyn Wadley, Honorary Professor, School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand
Christine Sievers, Senior lecturer, Archaeobotany, University of the Witwatersrand
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/126729
2019-12-06T13:09:23Z
2019-12-06T13:09:23Z
Why it can be hard to stop eating even when you’re full: Some foods may be designed that way
<figure><img src="https://images.theconversation.com/files/305463/original/file-20191205-39005-ezky0p.jpg?ixlib=rb-1.1.0&rect=49%2C0%2C6667%2C3460&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Bet you can't eat just one.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/many-chocolate-chip-cookies-stacked-662212138">tlindsayg/Shutterstock</a></span></figcaption></figure><p>All foods are not created equal. Most are palatable, or tasty to eat, which is helpful because we need to eat to survive. For example, a fresh apple is palatable to most people and provides vital nutrients and calories. </p>
<p>But certain foods, such as pizza, potato chips and chocolate chip cookies, are almost irresistible. They’re always in demand at parties, and they’re easy to keep eating, even when we are full. </p>
<p>In these foods, a synergy between key ingredients can create an artificially enhanced palatability experience that is greater than any key ingredient would produce alone. Researchers call this <a href="https://doi.org/10.1002/oby.22639">hyperpalatability</a>. Eaters call it delicious. </p>
<p>Initial studies suggest that foods with two or more key ingredients linked to palatability – specifically, sugar, salt, fat or carbohydrates – can activate brain-reward neurocircuits similarly to drugs like <a href="https://doi.org/10.1038/nn.2519">cocaine</a> or <a href="https://doi.org/10.1111/j.1467-789X.2012.01031.x">opioids</a>. They may also be able to bypass mechanisms in our bodies that make us feel full and tell us to stop eating. </p>
<p>Our research focuses on <a href="https://fazzinolab.drupal.ku.edu/publications">rewarding foods</a>, <a href="https://scholar.google.com/citations?user=odLm9LkAAAAJ&hl=en">addictive behaviors and obesity</a>. We recently published a study with nutritional scientist <a href="http://www.kumc.edu/school-of-health-professions/dietetics-and-nutrition/our-people/sullivan.html">Debra Sullivan</a> that identifies <a href="https://doi.org/10.1002/oby.22639">three clusters of key ingredients</a> that can make foods hyperpalatable. Using those definitions, we estimated that nearly two-thirds of foods widely consumed in the U.S. fall into at least one of those three groups. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/aCUbvOwwfWM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Documentaries like “Fed Up’ (2014) have linked obesity to food industry practices and American eating habits.</span></figcaption>
</figure>
<h2>Cracking the codes</h2>
<p>Foods that are highly rewarding, easily accessible and cheap are everywhere in our society. Unsurprisingly, eating them has been <a href="https://doi.org/10.1016/j.neubiorev.2014.12.002">associated with obesity</a>. </p>
<p><a href="http://fedupmovie.com/#/page/home">Documentaries</a> in the last 15-20 years have reported that food companies have developed formulas to make palatable foods so enticing. However, manufacturers typically guard their recipes as trade secrets, so academic scientists can’t study them.</p>
<p>Instead, researchers have used descriptive definitions to capture what makes some foods hyperpalatable. For example, in his 2012 book ”<a href="https://us.macmillan.com/books/9781596438316">Your Food Is Fooling You: How Your Brain Is Hijacked by Sugar, Fat, and Salt</a>,“ <a href="https://en.wikipedia.org/wiki/David_A._Kessler">David Kessler</a>, former Commissioner of the U.S. Food and Drug Administration (FDA), wrote:</p>
<blockquote>
<p>"What are these foods? …. Some are sweetened drinks, chips, cookies, candy, and other snack foods. Then, of course, there are fast food meals – fried chicken, pizza, burgers, and fries.” </p>
</blockquote>
<p>But these definitions are not standardized, so it is hard to compare results across studies. And they fail to identify the relevant ingredients. Our study sought to establish a quantitative definition of hyperpalatable foods and then use it to determine how prevalent these foods are in the U.S. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/305478/original/file-20191205-38993-1imt92a.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In 2018, 31% of U.S. adults aged 18 and over were obese.</span>
<span class="attribution"><a class="source" href="https://www.cdc.gov/obesity/downloads/2018-overall-obesity-prevalence-map-508.pdf">CDC</a></span>
</figcaption>
</figure>
<h2>Three key clusters</h2>
<p>We conducted our work in two parts. First we carried out a literature search to identify scientific articles that used descriptive definitions of the full range of palatable foods. We entered these foods into standardized nutrition software to obtain detailed data on the nutrients they contained.</p>
<p>Next we used a graphing procedure to determine whether certain foods appeared to cluster together. We then used the clusters to inform our numeric definition. We found that hyperpalatable foods fell into three distinct clusters: </p>
<p>– Fat and sodium, with more than 25% of total calories (abbreviated as kcal) from fat and at least 0.30% sodium per gram per serving. Bacon and pizza are examples.</p>
<p>– Fat and simple sugars, with more than 20% kcal from fat and more than 20% kcal from simple sugars. Cake is an example.</p>
<p>– Carbohydrates and sodium, with over 40% kcal from carbohydrates and at least 0.20% sodium per gram per serving. Buttered popcorn is an example.</p>
<p>Then we applied our definition to the U.S. Department of Agriculture’s <a href="https://data.nal.usda.gov/dataset/food-and-nutrient-database-dietary-studies-fndds">Food and Nutrient Database for Dietary Studies</a>, or FNDDS, which catalogs foods that Americans report eating in a <a href="https://www.cdc.gov/nchs/nhanes/about_nhanes.htm">biennial federal survey on nutrition and health</a>. The database contained 7,757 food items that we used in our analysis.</p>
<p>Over 60% of these foods met our criteria for hyperpalatability. Among them, 70% were in the fat/sodium cluster, including many meats, meat-based dishes, omelets and cheese dips. Another 25% fell into the fat/simple sugars cluster, which included sweets and desserts, but also foods such as glazed carrots and other vegetables cooked with fat and sugar. </p>
<p>Finally, 16% were in the carbohydrate/sodium cluster, which consisted of carbohydrate-dense meal items like pizza, plus breads, cereals and snack foods. Fewer than 10% of foods fell into multiple clusters.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=373&fit=crop&dpr=1 600w, https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=373&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=373&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=468&fit=crop&dpr=1 754w, https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=468&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/305561/original/file-20191206-38993-9v09ef.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=468&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Many hyperpalatable foods are widely available and cheap.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/drive-thru-neon-sign-129053336?src=4a432e34-7b41-4706-81cf-d989ed0bc7a9-1-0">gabriel12/Shutterstock</a></span>
</figcaption>
</figure>
<p>We also looked at which of the USDA’s food categories contained the most hyperpalatable foods. Over 70% of meats, eggs and grain-based foods in the FNDDS met our criteria for hyperpalatability. We were surprised to find that 49% of foods labeled as containing “reduced,” “low”, or zero levels of sugar, fat, salt and/or calories qualified as hyperpalatable. </p>
<p>Finally, we considered whether our definition captured what we hypothesized it would capture. It identified more than 85% of foods labeled as fast or fried, as well as sweets and desserts. Conversely, it did not capture foods that we hypothesized were not hyperpalatable, such as raw fruits, meats or fish, or 97% of raw vegetables.</p>
<h2>Tackling obesity</h2>
<p>If scientific evidence supporting our proposed definition of hyperpalatable foods accumulates, and it shows that our definition is associated with overeating and obesity-related outcomes, our findings could be used in several ways.</p>
<p>First, the FDA could require hyperpalatable foods to be labeled – an approach that would alert consumers to what they may be eating while preserving consumer choice. The agency also could regulate or limit specific combinations of ingredients, as a way to reduce the chance of people finding foods that contain them difficult to stop eating. </p>
<p>Consumers also could consider the role of hyperpalatable foods in their own lives. Our team needs to do further work validating our definition before we translate it for the public, but as a first step, individuals can examine whether the foods they eat contain multiple ingredients such as fat and sodium, particularly at high levels. Recent surveys show increased interest among U.S. consumers in <a href="https://www.nielsen.com/us/en/insights/article/2019/what-food-related-causes-do-us-consumers-care-about-today/">making informed food choices</a>, although they often <a href="https://foodinsight.org/wp-content/uploads/2018/05/2018-FHS-Report-FINAL.pdf">aren’t sure which sources to trust</a>. </p>
<p>One starting point for people concerned about healthy eating is to consume foods that are unlikely to be hyperpalatable – items that occur naturally and have few or no additional ingredients, such as fresh fruit. As food writer Michael Pollan <a href="https://www.penguinrandomhouse.com/books/305288/food-rules-by-michael-pollan/">recommends</a>, “Don’t eat anything your great-grandmother wouldn’t recognize as food.” </p>
<p>[ <em>Get the best of The Conversation, every weekend.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklybest">Sign up for our weekly newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/126729/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tera Fazzino receives research funding from the National Institute of Alcohol Abuse and Alcoholism. No funding was received for the study reported in the article.</span></em></p><p class="fine-print"><em><span>Kaitlyn Rohde received funding from an Undergraduate Research Award from the University of Kansas Center for Undergraduate Research.</span></em></p>
Everyone knows it’s hard to stop eating potato chips or chocolate chip cookies. New research shows why: Certain combinations of fat, sodium, sugar or carbohydrates make them irresistible.
Tera Fazzino, Assistant Professor of Psychology; Associate Director of the Cofrin Logan Center for Addiction Research and Treatment, University of Kansas
Kaitlyn Rohde, Research Assistant, Cofrin Logan Center for Addiction Research and Treatment., University of Kansas
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/115621
2019-05-23T21:17:18Z
2019-05-23T21:17:18Z
Forget toast and oatmeal, low-carb breakfasts reduce sugar spikes in those with Type 2 diabetes
<figure><img src="https://images.theconversation.com/files/271026/original/file-20190425-121228-emj39k.jpg?ixlib=rb-1.1.0&rect=24%2C57%2C5439%2C3546&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Eating a low-carbohydrate breakfast could help curb cravings for treats later in the day -- a simple and powerful strategy not just for those with Type 2 diabetes, but for anyone looking to improve their diet.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p><a href="https://www.ncbi.nlm.nih.gov/books/NBK499830/">Keto</a>, <a href="https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/low-carb-diet/art-20045831">low-carb</a>, <a href="https://www.healthlinkbc.ca/health-topics/aba5112">low glycemic index</a>, <a href="https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/mediterranean-diet/art-20047801">Mediterranean</a>, <a href="https://www.heartandstroke.ca/get-healthy/healthy-eating/dash-diet">DASH diet</a>, <a href="https://www.heartuk.org.uk/very-low-fat-diet/introduction">low-fat</a>: there are a dizzying array of diets claiming to optimize health. Some are based on sound science and some are not.</p>
<p>For anyone living with Type 2 diabetes, a disease that affects about <a href="https://www.diabetesatlas.org/">one in 12 people globally</a>, figuring out what to eat can be even more confusing because their bodies have difficulty processing sugars.</p>
<p>When they eat carbohydrates — the sugars and starches found in many foods — they get large spikes in blood sugar. <a href="https://doi.org/10.2337/diabetes.54.6.1615">Poor control of blood sugar by the body can damage organs</a>, particularly blood vessels, eyes and kidneys.</p>
<p>The goal of my <a href="http://emil.ok.ubc.ca/">research lab</a> at the University of British Columbia’s Okanagan campus is to research diet and exercise interventions for the treatment and prevention of Type 2 diabetes. We conduct human studies testing how different lifestyle strategies impact blood glucose control and other health markers important for the management of this disease.</p>
<p>What does our science say about some of these fad diets? What are some simple strategies that those living with Type 2 diabetes can use to cut through the hype and improve their health?</p>
<p>The first is probably the simplest and easiest to implement: restrict carbohydrate-containing foods, like oatmeal and toast, at breakfast.</p>
<h2>A reversed circadian rhythm</h2>
<p>I have been using <a href="https://www.medtronicdiabetes.com/treatments/continuous-glucose-monitoring">continuous glucose monitoring</a> for 10 years to study how diet and exercise influence blood sugar control. From studying hundreds of individuals with Type 2 diabetes, I can point to one consistency: breakfast leads to the biggest glucose spike of the day.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274742/original/file-20190515-60529-1uczu64.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Oatmeal, fruits and yogurt may seem like a healthy breakfast, but it is high in carbohydrates.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>I always assumed this was due to the fact that typical Western breakfast foods, like cereal, toast, oatmeal and fruit, are high in carbohydrates.</p>
<p>However, it could also be that circadian rhythm — the internal clock that sets our 24-hour metabolism — is <a href="https://doi.org/10.1210/edrv.18.5.0317">“reversed” in Type 2 diabetes</a>. </p>
<p>Instead of waking up and being most glucose tolerant and insulin sensitive early in the day, circadian rhythm is disrupted in those with Type 2 diabetes — so that their bodies are even worse at handling carbohydrates in the morning. If they eat a typical breakfast they get a very pronounced glucose spike.</p>
<p>This led us to conduct our recent study, <a href="https://doi.org/10.1093/ajcn/nqy261">published in <em>The American Journal of Clinical Nutrition</em></a>, which asked the simple question: “What would happen to overall glucose control if people with Type 2 diabetes avoided carbohydrates at breakfast?”</p>
<h2>Desire for sweet foods lower</h2>
<p>As predicted, we completely eliminated the large breakfast glucose spike by providing a low-carbohydrate breakfast consisting of an egg, cheese and spinach omelette. </p>
<p>Not only that, blood sugar spikes after lunch and dinner were the exact same regardless of the breakfast. So overall exposure to damaging glucose spikes was improved and markers of glucose volatility were better with the simple switch to a very low-carbohydrate breakfast.</p>
<p>We also discovered that both pre-meal hunger and desire to eat sweet foods were lower at dinner on the low-carbohydrate breakfast day. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274749/original/file-20190515-60541-bllv2t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Could a breakfast omelette reduce your craving for ice-cream?</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>This suggests that eating a low-carbohydrate breakfast could reduce energy intake and help curb cravings for treats later in the day. A simple and powerful strategy not just for those with Type 2 diabetes, but for anyone looking to improve their diet.</p>
<p>It should be noted that encouraging findings are preliminary and we don’t know if all low-carbohydrate breakfast foods would lead to the same effects.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/is-the-food-industry-conspiring-to-make-you-fat-81537">Is the food industry conspiring to make you fat?</a>
</strong>
</em>
</p>
<hr>
<p>You might also be asking yourself, if breakfast glucose spikes are such a problem, then why didn’t you ask participants just to skip breakfast? We know from previous research that skipping breakfast is probably not the greatest idea for someone with Type 2 diabetes because it leads to exaggerated glucose spikes at lunch and dinner, and may lead to metabolic compensation — so that people eat more, or expend less energy, later in the day.</p>
<h2>Diabetes ‘remission’ with keto diet</h2>
<p>The second strategy for those with Type 2 diabetes in particular, is to follow a low-carbohydrate or ketogenic diet.</p>
<p>Evidence for the <a href="https://doi.org/10.3945/ajcn.115.112581">benefits of a keto diet for Type 2 diabetes are accumulating</a>, with studies showing that with the proper support and medical guidance, over 50 per cent of patients might be able to get their <a href="https://link.springer.com/article/10.1007/s13300-018-0373-9">condition into “remission.”</a></p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274744/original/file-20190515-60541-1qs3s50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A steak with grilled vegetables is a typical ‘keto’ meal.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>That means their blood glucose control is back to normal and they do not have to take glucose-lowering medications anymore. It’s an astounding and life-changing result for the many people who have become dependent on daily medications like insulin or metformin.</p>
<p>In the real-world though, adherence to any restrictive dietary patterns is generally poor. Some people can stick to it, but usually <a href="https://jamanetwork.com/journals/jama/fullarticle/200094?dom=pscau&src=syn">at least half of participants fall off the wagon within six to 12 months of starting any new diet</a>, whether low-carb or not.</p>
<h2>One or two low-carb meals</h2>
<p>There may also be some <a href="https://www.health.harvard.edu/staying-healthy/should-you-try-the-keto-diet">risks to a hardened ketogenic diet approach</a>. One recent study from my lab also warns that the occasional “cheat day” when on a strict ketogenic diet <a href="https://www.mdpi.com/2072-6643/11/3/489">might cause damage to blood vessels</a>.</p>
<p>Switching just one or two meals per day to low-carb could be an attainable goal that maximizes the benefits while also minimizing the potential risks for many individuals with Type 2 diabetes.</p>
<p>In an age when pharmaceuticals are the norm for managing most diseases, I’m encouraged to be discovering some simple alternatives that can be tested in scientific research studies. It’s not every day that we in the health fields see diseases seemingly reverse in our patients. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274748/original/file-20190515-60567-6mkz97.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Eating one or two low-carb meals a day could be an attainable goal.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Because normal circadian rhythm dictates that humans are most tolerant to glucose in the morning, this strategy might not optimal for someone without diabetes. However, the lower feelings of hunger later in the day, when a low-carbohydrate breakfast is consumed, might be attractive for lots of people who are trying to control their weight. </p>
<p>We hope to test out some of these ideas in the coming years as we continue our research on optimizing lifestyle approaches for Type 2 diabetes.</p><img src="https://counter.theconversation.com/content/115621/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan Little receives funding from the Canadian Institutes for Health Research, Michael Smith Foundation for Health Research, Natural Sciences and Engineering Research Council, and the Heart and Stroke Foundation of Canada. He has received funding from the Egg Farmer's of Canada and Egg Nutrition Center unrelated to the low-carbohydrate breakfast study discussed in this article. He is affiliated with the not-for-profit Institute for Personalized Therapeutic Nutrition as co-Chief Scientific Officer. He owns shares and consults for Metabolic Insights Inc., a for-profit company that is developing a non-invasive metabolic monitoring device. </span></em></p>
New research shows that eating a low-carbohydrate breakfast both reduces sugar spikes in the morning and reduces cravings for sweet foods in the evening, in people with Type 2 diabetes.
Jonathan Little, Associate Professor in the School of Health and Exercise Sciences, University of British Columbia
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/101864
2018-09-13T10:14:36Z
2018-09-13T10:14:36Z
Low-carb versus high-carb – is the evidence really contradictory?
<figure><img src="https://images.theconversation.com/files/236000/original/file-20180912-133889-1qqg3f2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1016283994?src=1X_JtX_-9rG7UVbZGTAs8Q-1-2&size=medium_jpg">marilyn barbone/Shutterstock.com</a></span></figcaption></figure><p>It isn’t surprising that people are confused about nutrition when the media presents different findings as gladiatorial battles: vegetarian versus carnivore, high-fat versus low-fat diets and, more recently, low-carb diets versus high-carb. But, when you dig down into the data, many of these studies are reporting surprisingly similar things – and this is the case with the latest studies reporting on carbohydrates and health.</p>
<p>Most of the supposedly contradictory findings on carbs come from two large observational studies, published a year apart. One is called PURE, the other, ARIC. Headlines for the <a href="https://www.thelancet.com/action/showPdf?pii=S0140-6736%2817%2932252-3">PURE study</a>, published in August 2017, said a low-carb diet with more fat was the answer to a <a href="https://www.telegraph.co.uk/news/2017/08/29/low-fat-diet-linked-higher-death-rates-major-lancet-study-finds/">longer and healthier life</a>. </p>
<p>But that finding was later contradicted by the <a href="https://www.thelancet.com/pdfs/journals/lanpub/PIIS2468-2667(18)30135-X.pdf">ARIC study</a>, which led to headlines saying that a low-carb diets could reduce your life expectancy by <a href="https://www.telegraph.co.uk/science/2018/08/17/low-carb-high-fat-diets-could-knock-years-lifespan-25-year-study/">five years</a>.</p>
<p>In fact, these “contradictory” studies had strikingly similar results – they both found that getting around half of your energy from carbs is associated with the lowest risk of dying early.</p>
<p>The view that a moderate amount of carbs is optimal for good health is supported by the press release on the PURE study from the <a href="https://fhs.mcmaster.ca/main/news/news_2017/moderate_consumption_of_fats_and_carbohydrates_best_for_health.html">researcher’s university</a> (McMaster University in Canada) as well as by reporting in the <a href="https://www.sciencedaily.com/releases/2017/08/170829091027.htm">scientific press</a>. So where did headlines such as “<a href="https://www.nytimes.com/2017/09/08/well/new-study-favors-fat-over-carbs.html">New study favours fat over carbs</a>” in the New York Times come from? </p>
<p>The PURE study, which examined the eating habits of about 136,000 people from 18 countries and checked on their health seven years later, found that the 20% of people with the lowest carbohydrate intake had a 28% lower risk of death during the study period. But the people in the lowest carb category still got 46% of their calories from carbs, which is not dissimilar to the <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf">UK guideline recommendation</a>. So the study did not favour fat over carbs as the headline suggested. </p>
<h2>What counts as high or low-carb?</h2>
<p>Before considering the amount of carbs that is optimal for our health, we first need to know how low-carb and high-carb are defined. </p>
<p>Studies typically describe carbohydrate intake as a percentage of energy, instead of an amount in grammes. There is no agreed definition of what constitutes low or high-carb intake – but above <a href="https://www.sciencedirect.com/science/article/pii/S0899900714003323#tbl1">45% of total energy intake is generally considered high, and below 26% is low</a>. However, the PURE and ARIC studies used different definitions. PURE described intakes above 60% as high-carb – and linked this level to an increased risk of premature death. </p>
<p>In the case of <a href="https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(18)30135-X/fulltext">ARIC</a>, which looked at the eating habits of about 15,000 people in the US for 25 years, it considered 70% and above to be a high intake.</p>
<p>Interestingly, this variation was also seen when it defined low-carb intake, which in ARIC was classified as any carb intake below 40% of total energy. This is much higher than many advocates of low and very low-carb diets recommend, typically 5-10% of dietary energy, or around 50g per day. </p>
<p>Although the ARIC paper discusses low-carb diets and restricting carbohydrates, it did not look at people who were actively pursuing a low-carb diet for weight management or for managing type 2 diabetes, which is very different. In this case the <a href="https://diabetes-resources-production.s3.eu-west-1.amazonaws.com/resources-s3/2018-03/1373_Nutrition%20guidelines_0.pdf">evidence suggests</a> that carefully planned, individualised approaches, including very low carb diets, can be safe and highly effective.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/AOJxfh0b3o8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Keto diet is an example of a very low-carbohydrate diet.</span></figcaption>
</figure>
<p>Both the ARIC and the PURE study found that there appears to be a sweet spot of about 50% of energy from carbohydrate, where the risk of dying during the study was lowest. Anything more or less than this was associated with an increased risk of premature death. It seems that moderation is key, not just with carbohydrates but also fat. </p>
<p>A deeper look at the ARIC study suggests that the potentially negative effects of a lower carbohydrate diet can be moderated if the diet is more plant based, despite containing more protein and fat, such as a diet rich in avocados, olives, nuts and seeds. This suggests there is something more than just carbohydrate, protein and fat in our food. </p>
<p>The logical conclusion from these studies is that we should think more about <a href="https://bjsm.bmj.com/content/early/2018/08/31/bjsports-2018-099799">overall diet</a> rather than single macronutrients. Indeed, this is what the <a href="http://www.fao.org/nutrition/education/food-dietary-guidelines/background/en/">Food and Agricultural Organisation of the United Nations</a> recommends.</p><img src="https://counter.theconversation.com/content/101864/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane Mellor is a director, council member and spokesperson of the British Dietetic Association</span></em></p>
Two large nutritional studies seem to have reported contradictory findings on carbs. But only if you believe the headlines.
Duane Mellor, Senior Lecturer in Human Nutrition, Coventry University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/101629
2018-09-05T07:52:10Z
2018-09-05T07:52:10Z
It’s eating fat that makes you fat, new mouse study suggests
<figure><img src="https://images.theconversation.com/files/234811/original/file-20180904-45166-fuwx1x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><p>Worldwide obesity has <a href="http://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight">tripled since 1975</a>, with 1.9 billion adults considered overweight. The condition now kills more people across the globe than underweight and malnutrition.</p>
<p>One of the NHS’s <a href="https://www.independent.co.uk/news/health/nhs-obesity-diabetes-prevention-smoking-cost-health-service-weight-loss-sugar-tax-eat-healthy-a8254426.html">biggest cost burdens</a>, a staggering <a href="https://www.nuffieldtrust.org.uk/news-item/can-the-nhs-help-tackle-the-uk-s-obesity-epidemic">70% of UK adults</a> are expected to have overweight or obesity by 2034. Obesity is a problem of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3302369/">energy balance</a>. If a person has more calories coming in than are going out, then the difference is generally stored as body fat. But what needs to be identified are the factors causing the imbalance of intake and spending in the first place. Why don’t humans have a control system that allows them to eat exactly what they need and no more? Understanding the answer to this question may help tackle the obesity epidemic.</p>
<p>There have been several explanations of why people sometimes overconsume calories. These generally revolve around the <a href="https://www.huffingtonpost.co.uk/entry/what-are-macronutrients-and-why-do-you-need-them_uk_5a155ed1e4b009b331ad7600">macronutrient</a> composition of our diets. Macronutrients consist of fats, protein and carbohydrates. One explanation for over-consumption of calories is called the <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/obr.12131">protein leverage hypothesis</a>. The idea is that we primarily eat food for its protein content. If the amount of protein falls in relation to the amount of fat and carbohydrate, then to meet our protein needs we overconsume calories.</p>
<p>An alternative is the <a href="https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2686146">carbohydrate-insulin model</a>. This maintains that it is carbohydrates that make us fat, because when we eat them they stimulate the production of <a href="https://www.endocrineweb.com/conditions/type-1-diabetes/what-insulin">insulin</a>, which promotes storage of the carbohydrates as fat and stimulates hunger to procure additional intake. This idea has become very popular in the wake of <a href="https://www.amazon.co.uk/Low-Carb-Diet-Books/b?ie=UTF8&node=5687274031">several books</a> that have spawned the whole “high fat-low carb” (HFLC) diet movement.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=421&fit=crop&dpr=1 600w, https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=421&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=421&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=529&fit=crop&dpr=1 754w, https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=529&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/234814/original/file-20180904-45172-1pqiij1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=529&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Over a quarter of adults in England and almost a third of adults in Scotland have obesity.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/obese-woman-cant-measure-waist-because-538621570">Shutterstock</a></span>
</figcaption>
</figure>
<p>The classic idea, however, is that what makes us fat is eating fat, because fat stimulates reward centres in our brains that encourage us to overeat. This has been called the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3254791/pdf/nihms330047.pdf">hedonic over-ride hypothesis</a>.</p>
<h2>Of mice and men</h2>
<p>You might think that testing between these ideas would be rather straightforward – simply expose people to the different diets and see who gets fat. But a randomised controlled trial in humans would never get permission because ethically it would not be acceptable to expose anyone to a trial where the expected outcome is gross obesity and a threat to their health.</p>
<p>So the best we can do is trial the diets in animals such as mice and see what happens to give us some clues as to what may happen in humans. We have recently completed such a <a href="https://www.sciencedirect.com/science/article/pii/S1550413118303929?via%3Dihub">study</a> using a total of 1,000 mice exposed to 30 different diets for three months (equivalent to nine years’ exposure in a human). </p>
<p>The study included 12 diets where the protein content varied between 5% and 30% and 12 diets varying the fat content from 8.3% to 80%. The fat composition was designed to mimic the composition of the average American diet. In all these diets the sugar content was held constant at 5%.</p>
<p>Finally, in the last six diets we held the fat and protein constant and let the sugar vary from 5% to 30%. The balance in all cases was made up of highly processed carbohydrates such as <a href="https://www.thespruceeats.com/what-is-corn-starch-1328466">corn starch</a>. We repeated the study on five different strains of mice including ones considered to be prone or resistant to obesity. Food intake and body weights were measured every day, and each week we used a small mouse MRI machine to quantify how fat they were.</p>
<p>The results of this massive experiment were very clear. First, changing protein levels had minimal impact on total calorie intake and body fatness. So the protein leverage idea was not supported. Second, when we fixed the protein and fat levels, varying sugar also had no significant impact on body fatness, possibly because the other carbohydrates in the diet were already highly refined. Nevertheless, higher levels of these carbohydrates were on average protective against weight gain, which does not support the carbohydrate-insulin model.</p>
<p>In fact, the only thing that made the mice fat was eating more fat in their diets. But the relationship was not linear. With up to around 50%-60% fat in the diet, the mice ate more food and put on more weight. However, at higher levels of fat they gained less weight. A mouse eating 80% fat in its diet increased in weight by about the same amount as one eating 30% fat. We don’t know exactly why, only that on these super high-fat diets the mice consumed fewer calories and didn’t gain as much weight.</p>
<h2>Looking at the results</h2>
<p>There are several limitations to this work. Crucially, these experiments were done on mice. While convenient and we know lots about their genetics and physiology, it is possible that mice might respond differently to humans.
However, a definitive experiment in humans cannot take place because of ethical concerns, so the hope is that mice can help us understand what is going on. There are a number of other limitations that are worth highlighting. Cost restrictions meant we were only able to study one sex of mice at a single age. So it’s possible these results would not replicate at older ages and in the opposite sex.</p>
<p>We also only gave the mice sugar as part of their diet, but <a href="https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/longterm-sucrosedrinking-causes-increased-body-weight-and-glucose-intolerance-in-normal-male-rats/7041112FF75AE2D7D1A63F67014B0F03">some studies</a> suggest that delivering it in drinking water has a bigger effect on fatness in rodents. Higher sugar levels than 30% by calories may also be an issue but we didn’t study them in this instance.</p>
<p>Overall our data suggests that if the responses of mice data do translate to humans, then if you are lean and want to avoid becoming fat, then the best strategy is to limit fat in your diet to less than 20% of overall calories. Sugar up to 30% of total calories in food may not be a major problem, but in liquid form it may be more of an issue. Protein levels appeared to make little difference.</p>
<p>But this advice applies only to people who are already lean and hoping to avoid putting on weight. Whether this is also the best strategy for someone who is already obese is not informed by our study. Fortunately, that is something that can be studied in human clinical trials.</p><img src="https://counter.theconversation.com/content/101629/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Speakman receives funding from the Chinese Academy of Sciences who funded the work described in this article.</span></em></p>
If you want to remain lean, this study of mouse diets suggests your fat intake should make up just a fifth of your overall calorie intake.
John Speakman, Chair in Zoology, University of Aberdeen
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/94780
2018-04-19T09:07:51Z
2018-04-19T09:07:51Z
Avoiding type 2 diabetes – there is more than one diet to choose from
<figure><img src="https://images.theconversation.com/files/214773/original/file-20180413-47416-bjkq7h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/531173668?src=TXTGCIo5xv1Wi72RhrHnnA-1-0&size=medium_jpg">Africa Studio/Shutterstock.com</a></span></figcaption></figure><p>If you have high blood glucose, but not high enough to be diagnosed with diabetes (so-called <a href="https://www.diabetes.org.uk/about_us/news/prediabetes-whats-it-all-about">prediabetes</a>) you may have been advised by your doctor to <a href="https://www.england.nhs.uk/wp-content/uploads/2016/08/dpp-service-spec-aug16.pdf">lose weight and to eat less fat and more fibre</a>. If this sounds a bit one-size-fits-all, you may be encouraged by the fact that other diets may work just as well, if not better, at warding off full-blown <a href="https://www.nhs.uk/conditions/type-2-diabetes/">type 2 diabetes</a>.</p>
<p>The advice to eat less fat, more fibre and lose a moderate amount of weight comes from a series of <a href="https://pdfs.semanticscholar.org/23f2/141bd0df4eeeb98a904c1cf54df0ae7fb4d6.pdf">large-scale, randomised controlled trials</a> showing that weight loss following this approach helps prevent type 2 diabetes in up to two thirds of people. However, the most important predictor of prevention in these trials was not the diet itself, but <a href="https://www.ncbi.nlm.nih.gov/pubmed/16936160">the weight loss</a>. The more weight a person loses, the lower their risk of type 2 diabetes. Even more exciting, weight loss prevents type 2 diabetes <a href="https://www.ncbi.nlm.nih.gov/pubmed/23451166">even if the person regains the weight</a>. </p>
<p>So what diets could be equally or more effective than a low-fat, high-fibre diet? Low-carbohydrate diets have been shown to produce <a href="https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/409791">more weight loss in the short-term</a>. If weight loss is the primary driver of type 2 diabetes prevention, then a well-formulated low-carbohydrate diet (high in non-starch vegetables, fruits, nuts and seeds) would probably be as effective as the current standard advice.</p>
<p>There is also growing evidence that adding protein to the diet may help <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0044731">control blood glucose levels</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/27765690">lower liver fat</a> (strongly linked to insulin resistance) and even help the <a href="http://care.diabetesjournals.org/content/36/7/1919">pancreas produce insulin</a>. The latter point is important because when a person has prediabetes, they lose the first-phase insulin response. This is the <a href="https://www.medscape.org/viewarticle/483307_2">rapid spike of insulin</a> that is produced as soon as blood glucose level rises. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214768/original/file-20180413-566-1mups.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">High protein seems to help control blood glucose levels.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/684710068?src=wU-meNy0P_90U0NTr6OwDA-1-0&size=medium_jpg">Syda Productions/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>The first-phase insulin response is a critical function that rapidly suppresses glucose release from the liver. It also encourages glucose to be taken up by the muscles after you eat. Without it, hyperglycaemia results and glucose stays <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC507316/">elevated for several hours after the meal</a>. Emerging evidence seems to indicate the protein somehow seems to help the pancreas increase this initial insulin spike. Small but promising trials suggest that increasing protein may be <a href="http://drc.bmj.com/content/4/1/e000258">better than a low-protein diet</a> at controlling blood glucose levels. </p>
<p>A recent <a href="http://www.directclinicaltrial.org.uk/">large clinical trial</a> (DiRECT), as well as a series of smaller <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3749351/">physiologial trials</a>, have shown that people with type 2 diabetes who rapidly lose a lot of weight are able to restore the first-phase insulin response. The effect seems to be greatest in people who haven’t had <a href="https://www.ncbi.nlm.nih.gov/pubmed/27002059">type 2 diabetes for long</a>. This suggests that the effect would be greater still in people with prediabetes. </p>
<p>The reduction in calories consumed seems to be an <a href="https://www.ncbi.nlm.nih.gov/pubmed/8077323">independent driver</a> of improved pancreatic function. In studies where people consume only 400kcal a day for seven days, the weight loss is minimal, but pancreatic function <a href="https://academic.oup.com/ajcn/article/95/3/609/4578299">seems to improve just the same</a>. </p>
<h2>More choice</h2>
<p>A recent large <a href="http://care.diabetesjournals.org/content/34/1/14">study</a> from Spain (PREDIMED) showed that a Mediterranean diet with extra virgin olive oil and added nuts helped prevent type 2 diabetes even though people did not lose weight. We don’t know for sure how extra virgin olive oil or nuts could help prevent type 2 diabetes, but there is a growing body of research suggesting that a group of compounds called <a href="https://www.ncbi.nlm.nih.gov/pubmed/28883903">polyphenols</a> found in these foods (and also coffee, tea, berries and red wine) have a variety of beneficial health effects. <a href="https://link.springer.com/content/pdf/10.1007/s11101-015-9429-x.pdf">Potentially</a> these polyphenols may help reduce the inflammation that can damage the pancreatic cells and cause insulin resistance. </p>
<p>The “best” diet is, of course, one that a person enjoys and fits with their lifestyle. So the dietary approaches above may not only be more effective than a low-fat, high-fibre diet (and this should be tested in large-scale trials), but would provide more choice for people looking to stop their prediabetes morphing into type 2 diabetes.</p><img src="https://counter.theconversation.com/content/94780/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicola Guess does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Official advice to prediabetics on the best diet to avoid type 2 diabetes suggests that there is only one option. The latest research suggests otherwise.
Nicola Guess, Lecturer, King's College London
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/94570
2018-04-11T20:04:52Z
2018-04-11T20:04:52Z
Research Check: is it true pasta doesn’t make you gain weight, and could even help you lose it?
<figure><img src="https://images.theconversation.com/files/214215/original/file-20180411-536-682yhi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pasta has a low glycaemic index.</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/EP8Qsfh1EQQ">Photo by chuttersnap on Unsplash</a></span></figcaption></figure><p>Most people think eating pasta will lead to weight-gain, but a <a href="http://bmjopen.bmj.com/content/8/3/e019438">recent study</a> found otherwise. It’s no suprise such a conclusion made headlines. </p>
<p>Business Insider <a href="https://www.businessinsider.com.au/study-finds-pasta-wont-make-you-gain-weight-2018-4?r=US&IR=T">claimed</a>:</p>
<blockquote>
<p>Eating pasta 3 times a week won’t make you gain weight, according to a new study – and it could even help you lose it</p>
</blockquote>
<p>And The Daily Meal <a href="https://www.thedailymeal.com/eat/pasta-weight-loss-study/040318">said</a>:</p>
<blockquote>
<p>Eat Pasta to Lose Weight, Study Says</p>
</blockquote>
<p>But before you get the pasta pot boiling, there’s an important provision to keep in mind. The groups of people who ate pasta and lost weight were following an overall low glycaemic index (GI) diet. This means that the weight loss wasn’t the result of eating pasta alone, but the effect of the low GI diet.</p>
<h2>What’s glycaemic index?</h2>
<p><a href="https://www.health.qld.gov.au/__data/assets/pdf_file/0026/143567/paeds_gi.pdf">Glycaemic index</a>, or GI, ranks foods that contain carbohydrates based from 0-100 on how quickly and to what level they raise your blood sugar after you’ve eaten them. The higher the GI, the faster and higher the rise in blood glucose concentration. </p>
<p>Foods ranked as having a low glycaemic index have a <a href="http://www.glycemicindex.com/index.php">GI of less than 55</a>. Medium GI foods are ranked between 55-70, while those with a GI greater than 70 have a high GI index.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=431&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=431&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=431&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=541&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=541&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214234/original/file-20180411-570-8l2t5m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=541&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Participants who ate pasta were also on a low GI diet.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>Pasta has a lower GI as does some multigrain bread, rolled oats, apples, oranges, sweet potato, sweetcorn, lentils and chickpeas, milk and cashew nuts. <a href="https://www.health.qld.gov.au/__data/assets/pdf_file/0026/143567/paeds_gi.pdf">High GI foods include</a> some white breads, corn flakes, jasmine rice, potato, watermelon and rice crackers.</p>
<p>Eating foods from the low-GI list more frequently than those on the medium or high GI list leads to an overall dietary pattern with a lower mean GI value. This is thought to be important in terms of regulating blood sugars and appetite, particularly for people with <a href="https://www.ncbi.nlm.nih.gov/pubmed/29562676">type 2 diabetes</a> and those who are <a href="https://www.ncbi.nlm.nih.gov/pubmed/23786819">overweight or obese</a>.</p>
<h2>How was the study conducted?</h2>
<p>The study design is called a <a href="https://en.wikipedia.org/wiki/Systematic_review">systematic review</a>, which combines a number of already published studies answering a similar question to generate an overall conclusion. In this case, the researchers analysed the results from 29 randomised controlled trials in adults – where diets including pasta (the main intervention) were compared with another type of diet (the control). </p>
<p>The trials reviewed had investigated the impact of eating pasta on body weight and other indicators of body composition including changes in body fat, waist circumference, waist-to-hip ratio, abdominal diameter and body mass index (BMI). The studies lasted for a median of 12 weeks and included 2,448 participants.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-whats-the-best-diet-for-weight-loss-21557">Health Check: what's the best diet for weight loss?</a>
</strong>
</em>
</p>
<hr>
<p>This review originally set out to see whether eating more pasta, independent of what else you were eating, affected body weight. However, the researchers didn’t find any studies that had tested whether eating <em>more</em> pasta impacted body weight. All of the studies included in the review looked at the effect of eating pasta as part of an overall dietary prescription to follow a low GI diet.</p>
<p>That the pasta diets tested were, in fact, low GI diets is a major provision to interpreting the results. This means that the pasta groups (active arms) included people following an eating pattern with an overall low GI, compared to the control arms where the dietary patterns had a higher GI.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=428&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=428&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=428&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=538&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=538&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214223/original/file-20180411-566-1z0qc9i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=538&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Rolled oats and apples are both low GI foods.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<h2>What were the results?</h2>
<p>The systematic review’s main findings were that eating pasta was associated with a greater mean reduction in body weight of about 630 grams, and a reduction in BMI of 0.26 kg per square metre more in the pasta eating groups compared to the controls. There were no significant differences between groups when it came to other indicators of body weight or body composition. </p>
<p>The authors concluded that eating pasta in the context of low GI dietary patterns does not negatively affect body fatness, and reduces body weight and BMI, compared with higher GI dietary patterns.</p>
<p>The amount of weight loss was similar (mean of 630 grams more in the pasta/low-GI group) in the studies that ran for less than 24 weeks, compared to those that ran for longer (mean of 570 grams more for the pasta/low GI group). When the sub-group of studies were examined in those with type 2 diabetes or adults with overweight or obesity, the results were similar. </p>
<p>This is important because it means people in these categories can eat and enjoy pasta without compromising their weight status. The catch is how much pasta was eaten on each occasion.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/got-pre-diabetes-heres-five-things-to-eat-or-avoid-to-prevent-type-2-diabetes-80838">Got pre-diabetes? Here's five things to eat or avoid to prevent type 2 diabetes</a>
</strong>
</em>
</p>
<hr>
<h2>Issues with portion sizes</h2>
<p>There were only 11 trials in which the amount of pasta eaten could be quantified, and the authors did not report how the dietary intake data was extracted from these trials and converted to serve sizes. This pasta intake data is a potential source of error. </p>
<p>The <a href="https://www.eatforhealth.gov.au/food-essentials/five-food-groups/grain-cereal-foods-mostly-wholegrain-and-or-high-cereal-fibre">Australian Guide to Healthy Eating</a> defines one serve of pasta as being equivalent to half a cup of cooked pasta. But internationally what is called a <a href="https://www.ncbi.nlm.nih.gov/pubmed/28899402">serving size</a> varies.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214220/original/file-20180411-577-1vcxkfn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There’s no international consensus on what constitutes one serving of pasta.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>The median number of pasta servings across the studies was reported as 3.3 per week, ranging from from nearly two to seven per week. In this group of studies, the mean weight loss was 700 grams more in the pasta eating low GI groups compared to higher GI groups. </p>
<p>Of note is that the median pasta intake in the pasta groups was not very high. The median of 3.3 equates to only 1.7 cups of cooked pasta per week, varying from 0.9-3.5 cups. In the trials where there was also a kilojoule restriction, the median pasta intake was 2.3 servings (1.2 cups) per week. </p>
<p>The authors also looked at whether there was a dose-response effect for eating pasta. This means they checked whether those who ate more pasta, lost more weight. The answer was no – there was no dose-response effect.</p>
<h2>So, what’s the verdict?</h2>
<p>So the conclusion of this study could equally, and perhaps more accurately, be that following a low GI diet reduces body weight and BMI compared with a high GI diet. And following a low-GI diet does not have a negative effect on body composition. </p>
<p>The authors suggest that future trials are needed to assess the effect of eating pasta over longer periods of time or in the context of other “healthy” dietary patterns. Overall though, rigorous reviews like the current one are excellent in helping to dispel diet myths, <a href="https://theconversation.com/six-common-questions-about-eating-carbs-during-pregnancy-answered-84595">particularly those related to carbohydrates</a>. <strong>- Clare Collins</strong></p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-a-balanced-diet-anyway-72432">What is a balanced diet anyway?</a>
</strong>
</em>
</p>
<hr>
<h2>Peer Review</h2>
<p>I believe this is a fair, and mostly accurate and balanced assessment of the study and its findings. </p>
<p>However, I would say it’s more accurate the conclusion of this study is that: Following a low GI diet <em>that includes pasta</em> reduces body weight and BMI more compared with a high(er) GI diet <em>that doesn’t include pasta</em>. <strong>- Rebecca Reynolds</strong></p><img src="https://counter.theconversation.com/content/94570/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research and Gladys M Brawn Research Fellow. She has received research grants from NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers and the Sax Institute. She was a team member conducting systematic reviews to inform the Australian Dietary Guidelines update and 2017 evidence review on dietary patterns for the Heart Foundation.</span></em></p><p class="fine-print"><em><span>Rebecca Charlotte Reynolds owns The Real Bok Choy, a nutrition and lifestyle consultancy. </span></em></p>
A recent study was reported to have found that eating pasta wouldn’t make you put on weight, This is actually true, so long as you’re following a low GI diet.
Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/89685
2018-01-31T10:10:38Z
2018-01-31T10:10:38Z
Low carb, Paleo or fasting – which diet is best?
<figure><img src="https://images.theconversation.com/files/204078/original/file-20180130-107676-rpirww.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/571277470?src=iRHf44RTR2HkwtN83qX_Vw-1-0&size=medium_jpg">Ekaterina Markelova/Shutterstock</a></span></figcaption></figure><p>At this time of year, we are bombarded with books and TV shows telling us what we should be eating and how best to lose weight. Particularly in vogue are low-carb diets, Paleo diets and intermittent fasting diets. But which diet is the most effective for sustained weight loss – not to mention good health?</p>
<p>First, let’s look at low-carb diets, which include <a href="https://en.wikipedia.org/wiki/Atkins_diet">Atkins</a>, <a href="https://www.bbcgoodfood.com/howto/guide/what-dukan-diet">Dukan</a> and, more recently, the <a href="https://www.penguin.co.uk/articles/video/2017/jul/the-pioppi-diet/">Pioppi</a> diet. The argument behind these diets is that carbohydrates are bad for us because they are broken down into glucose, which stimulates the release of insulin, and insulin helps the body store the energy from food as fat – especially around our middles. </p>
<p>What is missed in this argument is that it is not only carbohydrates that encourage us to make insulin. Foods high in protein and fat do this, too. Beef, for example, increases insulin to a similar level as <a href="https://www.ncbi.nlm.nih.gov/pubmed/9356547">breakfast cereals</a>.</p>
<p>Related to low-carb diets are the evolutionary-type approaches, such as the caveman diet and the Paleo diet. These diets recommend shunning processed foods and following a diet similar to that of our ancestors in the <a href="http://ajcn.nutrition.org/content/81/2/341.short">Paleolithic period</a> – a period that began about 2.6m years ago and ended about 12,000 years ago. </p>
<p>Definitions of this diet vary, but they tend to exclude grains, which often results in a low-carbohydrate diet. Dairy products are also avoided. Both low-carb and Paleo diets encourage eating plenty of fresh food, including vegetables, and little or no highly processed food.</p>
<p>Evidence suggests that low-carb diets can help you <a href="http://bjsm.bmj.com/content/51/2/133.short">lose weight</a>, reduce your risk of <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118377">type 2 diabetes</a> and, perhaps, your risk of <a href="https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/effects-of-lowcarbohydrate-diets-v-lowfat-diets-on-body-weight-and-cardiovascular-risk-factors-a-metaanalysis-of-randomised-controlled-trials/B8FBAC51C156D8CAB189CF0B14FB2A46">heart disease</a>. However, these three potential benefits are largely linked to the energy restriction they cause and are not directly related to avoiding carbohydrates. </p>
<p>The reason for the drop in energy (calorie) intake is that carbohydrates normally make up a large part of the Western diet. Banishing carbs makes it difficult to make up for the lost energy intake because the food industry is geared to providing plenty of carbohydrate-rich foods. </p>
<p>Other studies suggest that eating protein and fat keep you feeling full for longer, and may suppress appetite that way. However, more research is needed to prove this theory.</p>
<p>There is some evidence that a low-carb diet can help you lose weight, for up to <a href="https://academic.oup.com/jcem/article/88/4/1617/2845298">six months</a>. And a study of people with type 2 diabetes suggests that it can help reduce the need for diabetes medication, even <a href="https://www.ncbi.nlm.nih.gov/pubmed/29178536">after two years</a>. </p>
<p>The news is not all positive, though. Paleo diets, in particular, can cause side effects, such a <a href="http://www.mdpi.com/2072-6643/8/8/481/htm">diarrhoea, headaches and weakness</a>. And both Paleo and low-carb diets tend to be <a href="http://www.mdpi.com/2072-6643/8/8/481/htm">more</a> <a href="https://www.sciencedirect.com/science/article/pii/S0271531707002515">expensive</a> than a regular healthy diet (as per government guidelines), and require <a href="http://onlinelibrary.wiley.com/doi/10.1111/jhn.12527/abstract">careful planning</a> to meet nutritional needs.</p>
<h2>Fasting</h2>
<p>Intermittent fasting diets, such as the 5:2 diet and the warrior diet, are another recent fad. They usually involve going for 14 to 36 hours with few or no calories. </p>
<p>The 5:2 diet involves eating a normal amount of calories for five days of the week and eating reduced calories (25% of normal calorie intake) on two non-consecutive days. The warrior diet involves eating just one large meal a day.</p>
<p>These types of diets have been shown to result in weight loss. In a study <a href="https://www.nature.com/articles/ijo2010171">published in the International Journal of Obesity</a>, the 5:2 diet not only resulted in a loss of over 6kg, on average, in overweight and obese women, over a six-month period, it also improved several important markers of health, including LDL cholesterol, triglycerides and blood pressure. </p>
<p>The important thing for people embarking on fasting diets to remember is: you need to meet all of your nutritional needs, as per the UK government’s Eatwell guide. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=430&fit=crop&dpr=1 600w, https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=430&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=430&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/204063/original/file-20180130-107690-qt0yb2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Eatwell guide.</span>
<span class="attribution"><a class="source" href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/528196/Eatwell_guide_600dpi.jpg">Food Standards Agency</a></span>
</figcaption>
</figure>
<p>The diets we’ve discussed almost all recommend eating more vegetables and less sugar, refined carbohydrates and highly processed foods. The advocates of these diets differ on the role of fats and carbohydrates, but they all encourage people to think more about food and take control of the food they eat. </p>
<h2>Reclaiming the word ‘diet’</h2>
<p>The evidence seems clear, most diets are <a href="https://jamanetwork.com/journals/jama/fullarticle/1900510?utm_source=Silverchair%20Information%20Systems&utm_medium=email">equally effective</a> when it comes to weight loss. The important thing is to find a diet that <a href="https://jamanetwork.com/journals/jama/fullarticle/1900510?utm_source=Silverchair%20Information%20Systems&utm_medium=email">works for you</a> – one you can enjoy in the long term. </p>
<p>Perhaps we need to remember the origins of the word diet, coming from the Greek “diata”, meaning <a href="https://www.etymonline.com/word/diet">way of life</a>. This meaning has been adapted over time to mean a restriction. It’s time we reclaim the word diet for its true meaning, and look to find ways of eating that are both enjoyable and improve health. </p>
<p>What we have learned from countries where people live long and healthy lives is that they tend not to focus on specific diets – counting calories, fussing about carbs – instead they eat local produce that is affordable and enjoyable.</p>
<hr>
<p><em>More on evidence-based articles about diets:</em></p>
<ul>
<li><p><em><a href="https://theconversation.com/do-you-get-diabetes-from-eating-too-much-sugar-95833?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=IsItTrue">Do you get diabetes from eating too much sugar?</a></em></p></li>
<li><p><em><a href="https://theconversation.com/should-you-eat-breakfast-53129?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=IsItTrue">Should you eat breakfast?</a></em></p></li>
<li><p><em><a href="https://theconversation.com/why-frequent-dieting-makes-you-put-on-weight-and-what-to-do-about-it-69329?utm_source=TCUK&utm_medium=linkback&utm_campaign=TCUKengagement&utm_content=IsItTrue">Why frequent dieting makes you put on weight – and what to do about it</a></em></p></li>
</ul><img src="https://counter.theconversation.com/content/89685/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duane Mellor is director, council member and spokesperson of the British Dietetic Association</span></em></p><p class="fine-print"><em><span>Paul D McArdle receives funding from the National Institute for Health Research and volunteers on committees as a member of and Spokesperson for The British Dietetic Association.</span></em></p>
Diets aren’t just about losing weight. There are other things to consider.
Duane Mellor, Senior Lecturer, Coventry University
Paul D McArdle, Clinical Doctoral Research Fellow & Lead Clinical Dietitian, University of Birmingham
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/83217
2017-08-30T04:50:31Z
2017-08-30T04:50:31Z
New study finding fat isn’t as bad as carbs misses the point
<figure><img src="https://images.theconversation.com/files/183913/original/file-20170830-5668-31rv9i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What's more important to examine is whether the fat and carbs come from fruits and vegetables or doughnuts and candy. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><a href="http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)32252-3/fulltext">A new study</a> has added weight to the debate as to whether fat is better or worse for you than carbohydrates, in terms of risk of heart disease and early death. Unfortunately based on this study the jury’s still out, but it does highlight that we should focus on what foods people are eating, rather than just looking at components such as fat and carbohydrates. </p>
<p>Researchers looked at intakes of fat, carbohydrates and protein in more than 135,000 people from 18 low income countries (Bangladesh, India, Pakistan, and Zimbabwe), middle income countries (Argentina, Brazil, Chile, China, Colombia, Iran, Malaysia, occupied Palestinian territory, Poland, South Africa, Turkey) and high income countries (Canada, Sweden, United Arab Emirates). </p>
<p>They assessed dietary intakes based on questionnaires, and compared the results with death rates from heart disease and from all other causes. </p>
<p>Over 7.4 years of follow-up, 5,796 people died and 4,784 had major cardiovascular disease events, such as a heart attack or stroke. Interestingly, they found those with the highest intakes of total fat and sub-types of fat (saturated, unsaturated) compared to those with the lowest intakes, had a <em>lower risk</em> of dying from all causes. </p>
<p>There was a 21% <em>lower</em> risk of stroke among those with the <em>highest</em> saturated fat intakes compared to the lowest. However, when it came to the risk of having a heart attack or dying from heart disease, fats had no relationship with risk. </p>
<p>Interestingly, those consuming the highest percentage of total energy from carbohydrates had a 28% higher risk of early death, but no higher risk of having heart disease or dying from heart disease. </p>
<p>Although it hasn’t received as much attention, they also found a higher percentage energy intake from protein was associated with a 23% lower risk of early death and 15% lower risk of dying from causes other than heart disease. Animal protein intake was also associated with a lower risk of dying, but there was no significant association between plant protein and risk of early death.</p>
<h2>So what does this all mean?</h2>
<p>This study highlights that both carbohydrates and fat are important, but which foods you eat that contain fat or carbohydrate is even more important when it comes to how long you live. </p>
<p>The researchers found some differences between results for those living in Asian countries compared to other regions. For example there was no statistically significant difference in early death from all causes between those with the highest, compared to the lowest percentage of energy from carbohydrate for those living in Asian regions. But there was among those from non-Asian countries. </p>
<p>The analysis adds more weight to the global call to go beyond macro-nutrients (protein, fat and carbohydrate which are the major constituents of food) and to look carefully at actual food and drinks consumed. It matters whether your carbohydrates come from an apple, lentils or carrots compared to soft drink, doughnuts or pancakes. </p>
<p>The types of foods actually consumed could inform how changes in the food supply within lower and middle income countries relate to changes in death rates. They could also inform nutrition policies for countries experiencing a nutrition transition as they become more wealthy.</p>
<p>Overall, this study is very important, and a timely reminder of the need to continually update the evidence on diet disease relationships and to factor in what part of the world the individuals under study are from. But it’s not time to throw out the pasta, rice and bread and start guzzling tubs of fat. </p>
<p>It is time to pay more attention to nutrition and to focus on optimal eating patterns within each country. We need to stem the tide of <a href="https://en.wikipedia.org/wiki/Ultra-processed_products">ultra-processed</a> foods that disrupt healthier eating patterns. Studies from around <a href="https://www.ncbi.nlm.nih.gov/pubmed/28714425">the world show</a> that getting the ratio of ultra-processed to minimally processed foods <a href="https://www.ncbi.nlm.nih.gov/pubmed/27825941">back in balance</a> is key to <a href="https://www.ncbi.nlm.nih.gov/pubmed/28193285">improving the nutritional quality</a> of our overall diets.</p>
<h2>Dietary patterns and heart disease</h2>
<p>We recently reviewed the <a href="https://www.saxinstitute.org.au/publications/evidence-check-library/dietary-patterns-cardiovascular-disease-outcomes/">evidence on dietary patterns and heart disease</a>, where most research has been done in high income countries. </p>
<p><a href="https://www.saxinstitute.org.au/publications/evidence-check-library/dietary-patterns-cardiovascular-disease-outcomes/">Our report</a> highlighted that a number of dietary patterns that vary in fat and carbohydrate type and quality are associated with lower heart disease risk. What they have in common is that they are all high in vegetables, fruit, wholegrains and most includes legumes.</p>
<p>This new study provides support for a focus on improving the nutritional quality of macronutrients. In other words, it matters what foods you eat that contain high amounts of carbohydrates and fats. For example is the major source of carbohydrate coming from fruit and vegetables or is it added sugars and highly processed foods?</p>
<p>Close examination of the barriers and facilitators of consuming a healthy diet is warranted. In an earlier analysis of data from this new study, the team reported <a href="https://www.ncbi.nlm.nih.gov/pubmed/27567348">very low intakes of vegetables and fruit</a> with a mean combined intake of 3·8 servings a day. This varied from 2.1 servings of vegetables and fruit per day in low income countries up to 5.4 servings per day in high income countries. They found that the cost of fruits and vegetables relative to household income was high. </p>
<p>This highlights that to improve dietary patterns globally, we need people to eat more vegetables and fruit. To achieve that we must develop nutrition polices that support affordability of healthy food for all and stop arguing about whether fat is better than carbs. That just adds to the current confusion.</p><img src="https://counter.theconversation.com/content/83217/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research fellow. She has received a range of research grants including NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, the Heart Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers and the Sax Institute. She was a team member for the systematic review conducted to inform the 2013 revision of the Australian Dietary Guidelines and the 2017 evidence review on dietary patterns and heart disease for the Heart Foundation.</span></em></p>
Arguing about whether carbohydrates or fats are better misses the main point. To improve global health we need reduce intakes of ultra-processed foods and eat more minimally processed foods.
Clare Collins, Professor in Nutrition and Dietetics, University of Newcastle
Licensed as Creative Commons – attribution, no derivatives.