20 Sep 2017 Guest Blog: Downsizing for Public Health
Dr. Ashleigh Haynes and Dr. Eric Robinson are researchers at the University of Liverpool, Institute of Psychology Health and Society.
A recent report from the Royal Society for Public Health showed that on average, adults in the UK are offered an ‘upsell’ on food or drink products 106 times per year. Upselling – offering customers something additional or a larger portion for a small increase in price – might sound like a good deal. But this practice is worrying given what we know about the influence of portion size on calorie consumption.
Larger portions of food and drink encourage us to consume more, and in general, no one is immune to this effect. People of all ages, sizes, and genders are susceptible to eating more when served a large portion, and this is the case for a range of different types of food and drink products. Importantly, when we consume a large amount from a large portion, the evidence suggests that we don’t make up for it by eating less at the next meal. Therefore, over time, larger portion sizes are likely to increase caloric intake and contribute to weight gain.
Upselling aside, portion sizes of food and drink (both commercially available products and served in the home) have increased dramatically over the past few decades. This environmental change coupled with the evidence for the effect of large portion sizes on energy intake has promoted calls to make changes to the food environment to tackle obesity.
Our research at the University of Liverpool focuses on the effects of reducing portion sizes. In particular, do people ‘compensate’ or make up for reduced portion sizes by eating more of other foods or at later meals? Our initial findings suggest not. We found that a 30% reduction in the portion size of a lunchtime meal decreased energy intake, even when people were offered unlimited access to additional food. This suggests that reducing portion sizes of commercially available food products, could be an effective way of helping the nation eat less.
What other consequences might arise from reducing portion sizes in the marketplace? It is possible that as a result of being exposed to smaller portions of food, we might later select and consume smaller portions in the home. Other research from our group suggests that reducing portion sizes might ‘renormalize’ smaller portions. Just as we have become accustomed to ‘supersized’ portions over the past decades, widespread reduction to portion sizes might readjust what we see as a ‘normal’ or appropriately sized portion. This change in what is seen as a ‘normal’ portion is likely to lead people to choose a smaller amount of food in future.
So as well as reducing consumption of commercially-available foods, widespread reductions to portion sizes could also have positive ‘downstream’ effects by reducing the amount of food people choose to serve and consume in their own homes; they would make smaller the new normal. The mounting evidence on downsizing portions therefore supports calls to legislate reductions to food portion sizes available for purchase in our supermarkets, shops, and restaurants.
Interested in taking part in research? Find a list of current studies here.