Eating Behaviors Among Weight-Discordant Siblings

The study used a discordant sibling design to compare putative obesity-promoting eating traits among siblings, 5-12 years, who were raised in the same household, but were discordant for weight status (normal-weight: BMI-for-age between 5 and less than the 85th percentile; overweight/obese: BMI-for-age greater or equal to the 85th percentile). Forty-seven pairs of same-sex siblings (boys and girls) were recruited from the greater Philadelphia area to participate in a 4-week study during which their eating behaviors and body composition were assessed. The study tested the hypotheses that overweight/obese, compared to normal-weight, siblings exhibit 1) a weaker ability to compensate for calories, 2) a greater susceptibility towards eating in the absence of hunger, and 3) habitual dietary intakes that favor increased dietary energy density (kcal/g) and increased %energy derived from fat and caloric beverages. The use of a behavioral genetics design to study eating phenotypes among siblings is a unique approach to elucidate shared and non-shared environmental influences that can contribute to variations in weight status during childhood.

Inclusion criteria

• same-sex;
• weight discordant (normal-weight vs. overweight/obese);
• meet age criteria;
• like most foods that were served in the study.

Exclusion criteria

• serious medical conditions or medication use known to affect appetite, food intake and body weight;
• developmental or psychiatric conditions;
• food allergies or nutrient intolerances (including lactose intolerance).