Food reinforcement and parental obesity predict future weight gain in non-obese adolescents.

Background: Food reinforcement, the extent to which people are willing to work to earn a preferred snack food, and parental obesity are risk factors for weight gain, but there is no research comparing the predictive effects of these factors for adolescent weight gain. Methods: 130 non-obese adolescents (M age = 15.2 ± 1.0; M BMI = 20.7 ± 2.0; M zBMI = 0.16 ± 0.64) at differential risk for weight gain based on parental obesity completed baseline food and money reinforcement tasks, and provided zBMI data over a 2-year follow-up. Results: The number of obese (BMI ≥ 30) parents (p = 0.007) and high food reinforcement (p = 0.046) were both significant independent predictors of greater zBMI increases, controlling for age, sex, parent education and minority status. Having no obese parents or being low or average in food reinforcement was associated with reductions in zBMI, but those high in food reinforcement showed larger zBMI increases (0.102) than having one obese parent (0.025) but less than having two obese parents (0.177). Discussion: Food reinforcement and parental obesity independently predict future weight gain among adolescents. It might be fruitful for obesity prevention programs to target both high risk groups.