Whether Smaller Plates Reduce Consumption Depends on Who's Serving and Who's Looking: A Meta-Analysis

Abstract

The literature on whether varying plate size has an effect on consumption is mixed and contradictory. This meta-analysis of 56 studies from 20 papers shows that varying the size of the container holding food (e.g., plate or bowl) has a substantial effect on amount self-served and/or consumed (Cohen’s d=.43). More generally, we found a doubling of plate size increased the amount self-served or amount consumed by 41%. Our analysis resolves the various contradictions of past reviews: we found that the plate size-effect had a substantial effect on amount served (d=.51), and on amount consumed when the portion was self-served (d=.70) or manipulated along with (confounded with) plate size (d=.48). However, plate size had no effect on amount consumed when the portion size was held constant (d=.03). Overall, plate size had a stronger effect when participants were unaware that they were participating in a food study (d=.76).

Keywords: plate size, portion size, food consumption