Will smaller plates lead to smaller waists? A systematic review and meta‐analysis of the effect that experimental manipulation of dishware size has on energy consumption

Abstract

It has been suggested that providing consumers with smaller dishware may prove an effective way of helping people eat less and preventing weight gain, but experimental evidence supporting this has been mixed. The objective of the present work was to examine the current evidence base for whether experimentally manipulated differences in dishware size influence food consumption. We systematically reviewed studies that experimentally manipulated the dishware size participants served themselves at a meal with and measured subsequent food intake. We used inverse variance meta-analysis, calculating the standardized mean difference (SMD) in food intake between smaller and larger dishware size conditions. Nine experiments from eight publications were eligible for inclusion. The majority of experiments found no significance difference in food intake when participants ate from smaller vs. larger dishware. With all available data included, analysis indicated a marginal effect of dishware size on food intake, with larger dishware size associated with greater intake. However, this effect was small and there was a large amount of heterogeneity across studies (SMD: -0.18, 95% confidence interval: -0.35, 0.00, I(2) = 77%). Evidence to date does not show that dishware size has a consistent effect on food intake, so recommendations surrounding the use of smaller plates/dishware to improve public health may be premature.

Dishware size and snack food intake in a between-subjects laboratory experiment

“…However, there may of course be specific contexts or study designs which are conducive to dishware size influencing food consumption. For example, it may be the case that plate or bowl size only influences food intake if consumers are not allowed to serve themselves multiple times and refill their plate or bowl (10,11) . Further work testing this and identifying the conditions in which dishware size does v. does not influence food consumption would now be useful.…”

“…There are, of course, other plausible explanations which might explain why most studies have not replicated the previously reported dishware size effects on food intake. One is that earlier studies in this field tended to be conducted in field settings and because of this may be more likely to have potential methodological limitations or flaws (see Robinson et al (10) for a discussion).…”

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

“…We note that while some previous reviewers focused on amount consumed (Libotte et al 2014;Robinson et al 2014b), they did appear to include some studies measuring amount self-served (e.g., Van Ittersum and Wansink 2013).…”

“…First, and in line with Robinson et al (2014b), we distinguish between manipulation of area whether reported as diameter (e.g., Rolls et al 2007) or area (e.g., Koh 2. We excluded studies that manipulated the size and number of containers simultaneously.…”

“…Robinson and Matheson (2015) in another qualitative review concluded that "smaller diameter plates [and] bowls" reduce consumption while acknowledging that there were some studies that showed no effect. In the only metaanalysis (quantitative review), Robinson et al (2014b) concluded that "evidence to date does not show that dishware size has a consistent effect on food intake." Finally, Libotte et al (2014) in another qualitative review noted that despite widespread recommendations to use plate size to control portions, "the evidence to support this is contradictory.…”