How does plate size affect estimated satiation and intake for individuals in normal-weight and overweight groups?

OBJECTIVE

Manipulating plate sizes could possibly introduce perceptual biases for judging food satiation and intake, which is thought to be related to the Delbeouf illusion - a visual illusion based on the perceived size of one object related to another. This study was to investigate whether an association exists between an individual's susceptibility to the plate-size-effect and their weight status (i.e. normal-weight versus overweight).

METHODS

The study assessed the effect of plate size amongst normal-weight (N = 124) and overweight (N = 79) New Zealand Europeans. All participants were asked to rate estimated satiation (ES) and intake (EI) on Visual Analogue Scales for 20 food images, which comprised photographs of ten different dishes placed on large versus small plates. These responses were analysed by mixed-model ANCOVA.

RESULTS

The results showed that the plate size had significant effects on ES (F_{(1, 1986)} = 19.14, p < 0.001) and EI (F_(1,1986) = 5.25; p = 0.048), with the small plate associated with higher ES and lower EI than the large plate. Significant differences in ES and EI were also evident across the weight groups (ES: F_(1,1986) = 4.26, p = 0.039; EI: F_(1,1986) = 42.22, p < 0.001), with the normal-weight group reported higher ES and lower EI than the overweight group. Furthermore, the weight group and the plate-size-effect were found to be involved in a significant interaction for EI. Post-hoc tests showed that the plate size only had a significant effect for the normal-weight group (p < 0.05), but not for the overweight group.

CONCLUSIONS

Overall, the study demonstrated that the normal-weight and overweight group differed in their susceptibilities to the plate-size-effect (reflected by EI). This study revealed some potential moderators for the plate-size-effect, such as the type of dish, and its associated appeal and familiarity, and provided useful indications about the effectiveness of small plates for food reduction.

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

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.

Plate size does not affect perception of food portion size

BACKGROUND

Evidences have suggested that larger utensils may provoke 'size-contrast illusions', influencing the perceived volume and food consumption.

OBJECTIVE

To analyse the influence of plate size on the visual estimate of food portion size.

METHODS

Two 400 g portions of pasta with tomato sauce were presented on two plates of different diameters (24.0 and 9.0 cm). Each participant visually estimated on an individual basis the quantities of the pasta portions (g) present on each plate. In addition, each subject classified the size of the portions on each plate as 'small', 'medium' and 'large'. The mean estimates of the amount of pasta on each plate were compared by the nonparametric Mann-Whitney. The differences in the frequencies of portion classifications between plates were evaluated by the chi-squared test.

RESULTS

Forty-eight students (average 25.8 ± 8.9 years) participated in the study. There was no difference in the median amount of pasta estimated for the large and small plates (150 g; range 50-500 and 115 g; range 40-500 g, respectively). The classification of the portion size as 'large' was reported by a significantly greater number of persons when they evaluated the amount of pasta arranged on the large plate compared to the small plate (47.9 versus 22.9%, respectively; P = 0.018).

CONCLUSION

The size of the plate did not influence the estimate of food portions, even though it did influence the classification of portion size.

Plate size and children's appetite: effects of larger dishware on self-served portions and intake

OBJECTIVES

Dishware size is thought to influence eating behaviors, but effects on children's self-served portion sizes and intakes have not been studied. We aimed to evaluate whether larger dishware increased children's self-served portion sizes and intake during meals.

METHODS

A within-subjects experimental design was used to test the effects of dishware size (ie, plates and bowls) on children's self-served portion sizes and intakes in a naturalistic setting. Subjects were predominantly African American elementary school-aged children (n = 42) observed on repeated occasions during school lunch. Children served themselves an entree and side dishes using either child- or adult-size dishware, which represented a 100% increase in the surface area of plates and volume of bowls across conditions. Condition order was randomly assigned and counterbalanced across 2 first-grade classrooms. Entrées of amorphous and unit form were evaluated on separate days. Fruit and vegetable side dishes were evaluated at each meal. Fixed portions of milk and bread were provided at each meal.

RESULTS

Children served more energy (mean = 90.1 kcal, SE = 29.4 kcal) when using adult-size dishware. Adult-size dishware promoted energy intake indirectly, where every additional calorie served resulted in a 0.43-kcal increase in total energy intakes at lunch (t = 7.72, P = .001).

CONCLUSIONS

Children served themselves more with larger plates and bowls and consumed nearly 50% of the calories that they served. This provides new evidence that children's self-served portion sizes are influenced by size-related facets of their eating environments, which, in turn, may influence children's energy intake.