Energy intake, parental control of children's eating, and physical activity in siblings discordant for adiposity.

Studying siblings discordant for adiposity allows for identifying risk factors for obesity by testing whether there is low familiality or resemblance of energy balance behaviors and then whether sibling differences in these behaviors are associated with differences in their adiposity. Nineteen sibling pairs discordant for overweight were assessed for physical activity, laboratory-based food consumption (single food, variety of foods), and parental control of child feeding behaviors. There was virtually no familiality for physical activity and energy intake during a single food meal. Sibling differences in moderate-to-vigorous physical activity (MVPA) and energy intake independently predicted differences in their adiposity. There was high familiality for increased energy intake (responsivity) when presented with a meal composed of a variety of foods, and sibling differences in responsivity did not predict sibling differences in adiposity. Parent concern and monitoring of child eating had only slight familiality and were associated with sibling differences in adiposity. In conclusion, sibling differences in MVPA and energy intake and parent concern and monitoring of child eating may promote differences in adiposity. Increased responsivity to dietary variety by overweight siblings does not appear to promoting sibling discordance in overweight as normal weight and overweight siblings responded similarly to dietary variety.