Whether smaller plates reduce consumption depends on who’s serving and who’s looking: a meta-analysis

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 orbowl) has a substantial effect on amount self-served and/or consumed (Cohen’s d 5 .43). More generally, we found adoubling of plate size increased the amount self-served or amount consumed by 41%. Our analysis resolves the variouscontradictions of past reviews: we found that the plate-size effect had a substantial effect on amount self-served (d 5.51) and on amount consumed when the portion was self-served (d 5 .70) or manipulated along with (confoundedwith) plate size (d 5 48). However, plate size had no effect on amount consumed when the portion size was held constant(d 5 .03). Overall, plate size had a stronger effect when participants were unaware that they were participatingin a food study (d 5 .76).