“Part of the reason moderation messages are so appealing — their simplicity — is part of the problem. People are poor judges of moderate consumption, partly because the standard for moderate consumption is left up to the individual,” write US-based researchers, led by Michelle van Dellen from the University of Georgia.
Van Dellen et al conducted a series of experiments finding that, rather than defining moderation as an objective standard, people tend to define the concept of moderation to justify how much they actually eat, or want to eat. The researchers found that around two thirds of the participants believed a moderate amount of cookies was more than what they 'should' eat.
“[The] results suggest that the endorsement of moderation messages allows for a wide range of interpretations of moderate consumption. Thus, we conclude that moderation messages are unlikely to be effective messages for helping people maintain or lose weight,” write the authors.
In light of the results, the authors have called for clearer serving sizes on-pack, arguing that current serving sizes do not accurately reflect the amount that people actually consume. Soft drink bottles, for instance, tell people how much of their energy intake will come from one serving - but bottles often contain multiple servings, they say.
"An important next step in reducing the obesity rate involves further understanding how and why moderation is misinterpreted and misapplied to eating behaviour," they write.
In the first experiment of the three-part study, the researchers gave 89 female participants a plate piled with 24 chocolate chip cookies and asked them to specify: how many cookies one should eat; how many they considered to be moderate consumption and how many cookies would constitute an indulgent amount. Only 8.99% defined moderation as being less than what one should consume while more than two thirds (67.4%) defined moderation as greater than what they believed one should consume.
Experiment two extended this to show 294 male and female subjects an image of fruit-shaped gummy sweets and asked them to rate their liking of the sweets. They found that the more people reported liking and eating gummy sweets, the more pieces they considered to represent moderate consumption.
Finally, in experiment three, subjects reflected on moderation messages for categories of foods: soft drinks, alcoholic drinks, ice cream and fast food. Again, the more people reported eating of a particular category, the more they were considered to fall within moderate consumption.
This is not the first time the efficacy of ‘everything in moderation’ has been questioned.
Last year a 7000-strong US survey spanning ten years and published in PloS One found that diet diversity was not associated with positive outcomes for diabetes or trimmer waists.
"An unexpected finding was that participants with greater diversity in their diets, as measured by dissimilarity, actually had worse diet quality. They were eating less healthy foods, such as fruits and vegetables, and more unhealthy foods, such as processed meats, desserts and soda," said lead author Marcia C de Oliveira Otto. "This may help explain the relationship between greater food dissimilarity and increased waist circumference."
Senior author Dariush Mozaffarian said: “These results suggest that in modern diets, eating 'everything in moderation' is actually worse than eating a smaller number of healthy foods.”
Source: Appetite Journal
Published online ahead of print 8 March 2016, doi:10.1016/j.appet.2016.03.010
“How do people define moderation?”
Authors: Michelle R van Dellen, Jennifer C Isherwood, Julie E Delose