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Monday’s medical myth: exercise makes you eat more food and gain weight

It’s time to ignore any advice you’ve heard about your sweat and hard work in the gym sabotaging your weight loss efforts by causing you to eat more. Every little bit of exercise can help shift unwanted…

Exercise decreases hunger in the long term. Puuikibeach/Flickr

It’s time to ignore any advice you’ve heard about your sweat and hard work in the gym sabotaging your weight loss efforts by causing you to eat more. Every little bit of exercise can help shift unwanted flab.

So, is dieting the only way to lose weight, or does it all boil down to becoming more active?

Some argue weight loss is all about how much (or how little) a person eats, while others support the view that it’s mostly a person’s activity (or lack of it) that most affects weight loss or gain.

A more extreme view that occasionally surfaces is that exercise only drives an increased appetite for food, and the extra calories consumed surpass those burned during the exercise.

If this is really the case, the argument becomes “why even bother getting active at all?”

Before this myth is dispelled by a wealth of scientific studies, a simple observation shows it’s false. Just look at any group of high performing athletes such as marathon runners, cyclists or swimmers. These athletes eat mountains of food each day but all of this is used up in their training endeavours. Overweight and obesity is hardly an issue for athletes.

So what does the science say?

A 2007 systematic review teased out the different effects that dieting and exercise can have on weight loss. The firm conclusion of the review wasn’t exactly surprising: exercise has a modest, but consistent benefit on body fat reduction and this benefit is independent of dieting.

The authors also found evidence to support a “dose” effect with increasing amounts of exercise leading to greater weight loss: the more you move, the more you lose.

Giving a small amount of credence to this myth though, the review did note that exercise can generate short-term increases in hunger that can cause a person to eat more. But in the longer term, there is an overall decrease in a person’s feelings of hunger.

Adding more evidence to debunk this exercise/weight-gain myth, a Cochrane Review concluded that exercise has a positive effect on body weight and cardiovascular disease risk factors in people who are overweight or obese, especially when combined with dietary changes.

Even if little weight is shed through this exercise, there are a myriad of health gains such as reduced risk of cardiovascular disease, and improved bone and muscle health, mood, sleep patterns, and even reduced cancer risk.

Now for the painful part.

Current Physical Activity Guidelines for Australians of 30 minutes of moderate-intensity activity on most days of the week may not be enough to stave off long-term weight gain.

For people who are already overweight, research shows that even 60 minutes of physical activity each day may not be enough to halt weight gain.

For those breaking out in a sweat just thinking about that much activity, what it really means is we need to pay more attention to the food side of the energy balance equation.

Join the conversation

6 Comments sorted by

  1. Terry Hilsberg

    Education startup investing

    A comment upon the accuracy of the article.

    Firstly, the science referenced in the article does not support it's conclusion. The Cochrane Review specifically referred to in the article (which only reviewed proper clinical trials) concludes that:

    "The pooled effect for interventions with a follow-up between 3 and 12 months was a reduction in weight of 1.1 kg (95% confidence interval (CI), 0.6 to 1.5) in the exercise and diet group compared with the diet alone group."

    So, the participants in…

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  2. Tim Crowe

    Associate Professor in Nutrition at Deakin University

    Thanks for your comments Terry, but you appear to have missed the context the article was written in: that of the myth that exercise causes weight gain. The Cochrane review (in addition to the other review article cited) validated that this is indeed a myth irrespective of the magnitude of overall weight loss by participants in the trials included. The end of my article acknowledged that the amount of exercise needed to have a meaningful effect on body weight is likely much larger than most people achieve, hence overall, exercise may not be a large factor for most people.

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  3. Douglas Cotton

    B.Sc.(Physics), B.A.(Econ), Dip.Bus.Admin

    The benefits of exercise extend beyond the burning of stored fat calories during the actual time spent exercising. It also leads to beneficial changes at the cellular level and improves insulin sensitivity. In so doing it mimics the effects of antidiabetic drugs which can impact favourably on fat distribution. In general, the effects can last possibly up to 48 hours after the exercise event.

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    1. Terry Hilsberg

      Education startup investing

      In reply to Douglas Cotton

      Tim,

      Given the emphatic nature of your response, this morning I again read the Cochrane Review looking for a quote that would support your view that ".....validated that this is indeed a myth irrespective of the magnitude of overall weight loss by participants in the trials included". I can find no such statement.

      Instead, all I can find in the Cochrane Review is reports from a bunch of clinical trials where people exercised for around 40 minutes on average (say a net additional calorie burn of…

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    2. Lauren Trevorrow

      Ms.

      In reply to Terry Hilsberg

      I have just read the Cochrane Review and it does appear to support the hypothesis that exercise contributes to weight gain - 'when combined with dietary changes'. And I am at a loss to understand why you would read this article and reach a such a negative judgment as to the quality of journalistic standards on this site.

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