In Phase II, individual clinical trials will be supported to test the efficacy of interventions developed in Phase I. Although the interventions developed by each field center will be unique, the centers will collaborate to standardize key measurements, outcomes, and main analysis methods. The Memphis Field Center will conduct a full-scale two year, randomized, controlled clinical trial for weight gain prevention among 300 high risk, preadolescent African American girls and their parents. Body mass index is the primary endpoint. Secondary endpoints include dietary intake, physical activity, and psychosocial variables. The Stanford Field Center will conduct a two-arm parallel group, randomized controlled trial to test the efficacy of an after school dance program and a family-based intervention to reduce television, videotape, and video game use to reduce weight gain among 260 African American preadolescent girls. An active placebo group will receive an information-based community health education intervention. Interventions will last for two years. Body mass index is the primary outcome measure.