Why Does Dieting Predict Weight Gain in Adolescents? Findings from Project EAT-II: A 5-Year Longitudinal Study

Abstract Objective Dieting has been found to predict weight gain in adolescents, but reasons for this association remain unclear. This study aimed to explore potential mechanisms by which dieting predicts weight gain over time in adolescents. Design Population-based, 5-year longitudinal study. Participants Adolescents (n=2,516) from diverse ethnic and socioeconomic backgrounds who completed Project EAT (Eating Among Teens) surveys in 1999 (Time 1) and 2004 (Time 2). Main Outcome Measure Body mass index (BMI) change over 5 years. Statistical Analysis Multiple regressions were used to examine associations between Time 1 dieting and Time 2 binge eating, breakfast consumption, fruit and vegetable intake, and physical activity. Associations were then examined between these behaviors and BMI change. Finally, to test for mediating effects, associations between dieting and BMI change were examined with and without the inclusion of these behaviors, and regression coefficients were compared. Results In female adolescents, dieting predicted increased binge eating ( P