Eating in larger groups increases food consumption.

OBJECTIVE To determine whether children's food consumption is increased by the size of the group of children in which they are eating. DESIGN Crossover study. SETTING University based preschool. PARTICIPANTS 54 children, aged 2.5-6.5 years. INTERVENTIONS Each child ate a standardised snack in a group of three children, and in a group of nine children. MAIN OUTCOME MEASURES Amount each individual child consumed, in grams. RESULTS Amount eaten and snack duration were correlated (r = 0.71). The association between group size and amount eaten differed in the short (<11.4 min) versus the long (> or =11.4 min) snacks (p = 0.02 for the interaction between group size and snack duration). During short snacks, there was no effect of group size on amount eaten (16.7 (SD 11) g eaten in small groups vs 15.1 (6.6) g eaten in large groups, p = 0.42). During long snacks, large group size increased the amount eaten (34.5 (16) vs 26.5 (13.8), p = 0.02). The group size effect was partially explained by a shorter latency to begin eating, a faster eating rate and reduced social interaction in larger groups. CONCLUSIONS Children consumed 30% more food when eating in a group of nine children than when eating in a group of three children during longer snacks. Social facilitation of food consumption operates in preschool-aged children. The group size effect merits consideration in creating eating behaviour interventions.