The effects of acute social ostracism on subsequent snacking behavior and future body mass index in children

Ostracism may lead to increased food intake, yet it is unclear whether greater reactivity to ostracism contributes to higher body mass index (BMI). We investigated whether children who exhibited greater stress to social exclusion subsequently consume more energy and whether this predicts BMI 6- and 18-months later.

Children (8.5 years-old) (N = 262, males = 50.4%; Chinese = 58.4%) completed a laboratory-based manipulation of social exclusion (the Cyberball task) prior to an ad-libitum snack. Heart rate variability (HRV) was measured during the inclusion and exclusion conditions and proportionate changes were calculated as a physiological measure of exclusion-related stress. Social anxiety and social-emotional assets were also measured as moderators.

Greater stress (as measured physiologically or by self-report) did not directly, or indirectly via energy intake, predict later BMI (at 9- and 10-years). However, among children reporting higher social anxiety, greater stress as measured by proportionate changes in HRV was associated with increased energy intake (B = 532.88, SE = 226.49, t(255) = 2.35, [CI₉₅ = 86.85,978.92]). A significant moderated mediation was also observed (index: (b = 0.01, _bootSE = 0.01, [CI₉₅ = 0.001, 0.036]), such that among children reporting higher social anxiety, greater stress from social exclusion predicted increased energy intake from a subsequent snack, which in turn predicted higher BMI 1.5 years later.

This prospective study suggests that a pattern of greater snack intake in response to heightened vulnerability to the effects of ostracism may contribute to increases in child BMI scores.