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Portion size is a subject for which a substantial body of research exists, however, we found that additional understanding of the topic can be gained by revisiting existing research. For this paper we analyzed multiple past studies to examine who is most portion-size prone, why portion size influences consumption, what factors influence portion distortion and how can we decrease our perceived portion-size norms.
Despite gender, BMI, and socioeconomic status, large-sized packages, restaurant portions, and dinnerware all perceptually suggest to us that it is more appropriate, typical, reasonable, and normal to serve and to eat more food than smaller plates or smaller packages suggest. 94% of demographically diverse diners in four field studies resolutely maintained that the amount of food they served themselves was not influenced by plate or package size. These same participants served themselves an average of 31% more food than the control groups.
In restaurants, supermarkets, at home, and in other settings individuals are influenced by portion size. At restaurants, people tend to eat 30-50% more than in other settings. In a “home” centered study with “bottomless” soup bowls, people eating soup from bottomless bowls ate 73% more soup than those eating from non-refilling bowls. However, those eating more estimated that they ate only 4.8 calories more. Furthermore, during one study, moviegoers were offered stale popcorn in a free medium or large-size bucket. Although they were not hungry and the popcorn was not of good quality, we found that people ate 51% more popcorn from the large than the medium bucket. With the introduction of less expensive generic products, the managers of many popular brands have realized that the best way to compete was not through price wars, but through size wars. Our desire for value at the cash register has resulted in acceptance and purchase of larger sizes that cost us less economically, but more in terms of our health. Individuals also to serve themselves, and eat, 20-40% more from larger packages. All of these findings demonstrate that portion distortions, such as large plates, large packages and bottomless bowls, afflict individuals in various settings.
The culmination of all presented studies indicates that in order to balance our mindless eating we need to eliminate large packaging and portions from our lives. This beneficial change can be done painlessly and in small steps, with many small solutions contributing to a greater overall lifestyle change. Examples of such solutions include: shoppers creating personalized single-portion servings by subdividing bargain-size bags into smaller ones, restaurant diners ordering two appetizes instead of an entrée, a home diner replacing large tableware with smaller dishware, and keeping large packages or containers off the table and out of sight.
Wansink, Brian and Koert Van Ittersum (2007). Portion Size Me: Downsizing Our Consumption Norms. Journal of the American Dietetic Association, 107(7),1103 – 1106. doi:10.1016/j.jada.2007.05.019