The Role of Tableware Size in Healthy Eating-Effects on Downstream Food Intake

Recent studies show that visual exposure to different portion sizes can lead to portion alterations in subsequent meals, suggesting that manipulations of tableware sizes may also modify portion size perception and downstream eating behaviour. The present study aims to address this novel question by testing 61 male participants (20-40 years; 19.7-41.5 kg·m^-2) over three breakfast sessions in a controlled laboratory. In each session, the participant was served a pre-determined breakfast portion in either medium (control; CT), small (SC), or large (LC) jars. Participants were asked to rate post-meal satiety, and then recorded food intake for the rest of the day using Food Records. Our results indicated significant changes in post-meal satiety following the SC or LC condition, compared to CT (SC: 55.3 ± 10.8, LC: 31.0 ± 8.4, CT: 42.1 ± 9.6, F_{(2, 108)} = 25.22, p < 0.001). SC led to a reduction in post-breakfast energy intake (F_{(2, 108)} = 61.28, p < 0.001), but was counteracted by a substantial increase in downstream intake at the following meal (F_{(2, 108)} = 47.79, p < 0.001), resulting in an overall increase in total daily energy intake (F_{(2, 108)} = 11.45, p < 0.001). This study provides the first evidence that small tableware may not be a long-term solution for addressing overeating and related health issues (e.g., obesity), reinforcing the importance of considering downstream intake in eating-related intervention.