Eating Responses to External Food Cues in Weight Discordant Siblings

Purpose: Heightened responsivity to external food cues may promote energy intake and account for differences in weight status between nonoverweight and overweight adolescents. Studies of weight-discordant fraternal siblings control for some genetic and shared within-family factors, which allow for testing of other nonshared factors relevant to sibling weight differences.The aim of the study was to determine whether same-sex weight-discordant (one nonoverweight and one overweight) adolescent siblings differ in responsiveness to external food cues. Methods: Weight-discordant siblings' (n = 38 pairs) energy consumption was compared following both an appetizing food (pizza) on one day and a control activity (reading) on another day. Multilevel models examined intrafamily similarity, and regressions examined associations with adiposity. Results: Siblings shared little similarity in cue responsivity (ρ = .10). However, sibling body mass index z-scores difference was not associated with differences in cue responsivity. Moreover, when tested as groups, nonoverweight and overweight siblings did not differ for cue responsivity (p > .84). Conclusion: Weight-discordant adolescent siblings show little similarity in responses to food cues. Differences in sibling weight status were not predicted by differences in responses to food cues. Thus, nonshared factors other than cue responsivity must contribute to weight differences of adolescent siblings.