Frosting on the Cake: Pictures on Food Packages Bias Serving Size
Consumers are heavily influenced by external cues when deciding how much to eat. Several studies have already demonstrated the legitimacy of the “pack size effect,” or the theory that large packages implicitly suggest that it’s normal to eat more than a standardized serving and, therefore, often coax consumers to unknowingly increase their portion sizes. Images on food packaging also encourage consumers to subconsciously over serve, as they often exaggerate the recommended serving size. The purpose of this study was to investigate if the “extras” depicted on food packaging (frosting on cake, in this instance) exaggerate how many calories are pictured and how they might lead consumers to eat more than a recommended serving.
Four studies were conducted to assess the effects of fifty-one different cake mixes. Study 1 compared the calories stated on the nutrition label with the calories of the cake and frosting pictured on the box. In Studies 2, 3 and 4, Cornell University undergraduates (Studies 2 and 3) or foodservice professionals (Study 4) were given one of the cake mix boxes depicting one slice from a round cake. Some were told that the frosting was not included on the nutritional labeling, while others were not provided with this information. They were all asked to indicate what they believed to be a reasonable serving size of cake.
The results from Study 1 indicate that the average calories of cake and frosting depicted on packages exceed the calories listed on the nutrition label by 134%. Studies 2 and 3 show that informing consumers that frosting is excluded from the package’s nutrition label reduces how much they serve. Study 4 showed that even foodservice professionals over serve themselves if not informed that frosting is not included on the nutrition labeling. These results have important implications for policy officials, as they indicate that combining appropriate serving size depictions with a clear message about what is included on nutritional labeling may be an effective way to convey appropriate serving size information to the public.