title: Portion size me: plate-size induced consumption norms and win-win solutions for reducing food intake and waste.
abstract: Research on the self-serving of food has empirically ignored the role that visual consumption norms play in determining how much food we serve on different sized dinnerware. We contend that dinnerware provides a visual anchor of an appropriate fill-level, which in turn, serves as a consumption norm (Study 1). The trouble with these dinnerware-suggested consumption norms is that they vary directly with dinnerware size--Study 2 shows Chinese buffet diners with large plates served 52% more, ate 45% more, and wasted 135% more food than those with smaller plates. Moreover, education does not appear effective in reducing such biases. Even a 60-min, interactive, multimedia warning on the dangers of using large plates had seemingly no impact on 209 health conference attendees, who subsequently served nearly twice as much food when given a large buffet plate 2 hr later (Study 3). These findings suggest that people may have a visual plate-fill level--perhaps 70% full--that they anchor on when determining the appropriate consumption norm and serving themselves. Study 4 suggests that the Delboeuf illusion offers an explanation why people do not fully adjust away from this fill-level anchor and continue to be biased across a large range of dishware sizes. These findings have surprisingly wide-ranging win-win implications for the welfare of consumers as well as for food service managers, restaurateurs, packaged goods managers, and public policy officials.
authors.affiliation: Dyson School of Applied Economics and Management, Cornell University.
authors.forename: Brian
authors.initials: B
authors.lastname: Wansink
authors.affiliation: Department of Marketing and Consumer Well-Being, University of Groningen.
authors.forename: Koert
authors.initials: K
authors.lastname: van Ittersum
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003297:Cooking and Eating Utensils; D004435:Eating / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064787:Portion Size / Q000523:psychology*; D012147:Restaurants; D012858:Size Perception; D055815:Young Adult