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Pre-committing to a grocery list may help in the battle of the bulge

Meal plans and shopping lists are a simple solution to a growing problem.

Obesity, we all know, is one of the greatest public health challenges that Australia faces and so-called “solutions” are ten a penny. But could something as obvious as making a shopping list make a realistic difference? We think it could.

Research we published recently in the journal Nutrition & Diabetes offers a simple but cost-effective solution: following detailed meal plans and shopping with a pre-determined grocery list, containing just the items needed for the planned meals.

Previous studies have shown that overweight or obese people in standard behavioural therapy who planned meals and shopped to a list lost around 0.67kg a month more than those who received just behavioural therapy.

Our study demonstrated that, although small, this weight loss was significant enough to reduce medical costs and improve quality of life.

What’s more, because planning meals and writing shopping lists could be carried out relatively cheaply, it’s a cost-effective weight-loss tool when compared to the alternatives of standard behavioural therapy and “doing nothing”.

Why does it work?

Meal plans and shopping to a list are examples of “pre-commitment”. This is an idea drawn from the relatively new discipline of behavioural economics that aims to help people to stick to a plan. Behavioural economic strategies draw on social, cognitive and emotional factors to “outsmart” our impulsive tendencies and overcome poor habits which prevent us from achieving our goals.

With meal plans and shopping to a list, people commit to healthy food choices before they are faced with unhealthy options and this makes it easier to resist those temptations. Other examples include packing a healthy lunch for work, pre-selecting menu items in school or work cafeterias, pre-ordering grocery items on supermarket websites and pre-selecting a list of foods to buy with a pre-paid card at the supermarket.

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Pre-commitment and other strategies from behavioural economics recognise that people often understand the implications of overeating and under-exercising and have good intentions to improve their diet and exercise more. However, overcoming ingrained habits and everyday temptations can be very challenging, especially in today’s obesogenic environment.

Trials and field experiments suggest that behavioural economic strategies can be much more effective than mainstream approaches to change current behaviour. And they have the additional benefit of being relatively cheap.

A new way to tackle obesity

With more than six out of ten adults and one-quarter of children classified as overweight or obese, existing public health approaches to tackling obesity have failed to reverse the obesity epidemic and new strategies are needed.

Behavioural economic strategies have been successfully applied to address problems in other aspects of people’s lives, such as making better decisions about pension and savings plans by setting better default options.

With government and corporate buy in, such strategies could easily be used to improve public health by, for example:

  • Altering the stock or layout of convenience stores or school cafeterias to make healthier foods more prominent

  • Communicating social norms to encourage use of stairs rather than elevators or active transport rather than car use for short trips

  • Designing menus such that healthier options are positioned in more prominent places (the top or the bottom of the list) to encourage healthier meal choices.

Almost two-thirds of Australians are overweight or obese. Image from

Importantly, such strategies allow individuals to retain their freedom of choice (unlike banning certain products), while at the same time nudging people towards healthier choices.

While novel strategies from behavioural economics offer great potential in the prevention and management of obesity, this potential remains largely untapped. It is only very recently that the United States and the United Kingdom have begun to consider how such strategies might be turned into public health policies.

Many of these strategies could be rolled out as government interventions to prevent or reduce obesity at the population level. However, there is presently a severe shortage of quality evidence on the effectiveness and cost-effectiveness of such strategies.

As obesity continues to rise in Australia, it is time to look to novel strategies. This requires a greater investment in understanding how well they work and how much they cost.

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