How portion distortion makes you overeat

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The following article is written by nutritionist Associate Professor Tim Crowe from Deakin University’s School of Exercise and Nutrition Sciences.

The larger the serving size of food, or the container it comes in, the greater likelihood a person will eat more of it. This effect, called portion distortion, can easily lead to passive over-consumption and with that real increases in the risk of obesity and its connected diseases.

Over the last few decades a fascinating field of research has studied that how food is presented, and the serving size given, can significantly affect how much of the food a person eats. Now researchers have combined the disparate research into a major scientific review with some stark conclusions.

Involving 72 research studies, the review looked at the influence of portion size, packaging size and tableware size on food consumption. The results were consistent in showing a greater likelihood to eat more food when the serving size, packaging or tableware were large compared to using smaller varieties of each.

Taking the research one step further, it was estimated that reducing exposure to larger serving sizes could reduce daily energy intake by between 12 and 16% for an adult living in the UK. In the face of the growing overweight and obesity problem, these are not insignificant numbers.

'It was estimated that reducing exposure to larger serving sizes could reduce daily energy intake by between 12 and 16%'

Associate Professor Tim Crowe,
Deakin University

What was interesting from the research was that the susceptibility to eat more with larger food sizes applied equally to men and women regardless of their body weight, susceptibility to hunger, or tendency to control their own eating behaviour. What this means is that all of us are affected by the subconscious cues to eat more when we are presented with a larger serving size or food or when it comes in larger tableware.

Large serving sizes and bigger packaging sizes appeal to our ‘sense of value’ which is wonderful if you were looking at buying washing powder, for example. But when it comes to food and eating, seeking ‘value for money’ with larger serves comes at most people’s detriment.

How to fight back

So how to combat our innate tendency to overeat? Consider making a conscious choice to self-serve smaller portions of kilojoule dense foods such as desserts, drinks and fatty foods. Or eat food from smaller bowls, plates, or cups. When shopping, be wary of the ‘two for one’ or ’30% more’ style label promotions on food, especially for confectionery and other snack items.

One of the leading researchers in the field is Dr Brian Wansink and he has lots of great resources on his website www.mindlesseating.org.

Want to study food and nutrition further? Check out Deakin University’s range of courses in the nutrition and dietetics. This piece first appeared on Tim Crowe’s website Thinking Nutrition, where you can find more information on eating and living well, exercise and weight management. 

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Tim Crowe
Tim Crowe

Associate Professor in Nutrition, School of Exercise and Nutrition Sciences, Deakin University
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