: Testing a Scalable Weight Control Intervention for Adolescents.

The goal of this randomized controlled trial was to compare the relative effectiveness of a comprehensive lifestyle intervention delivered through the YMCA, , with an enhanced version of this program that included on-site supervised group physical activity and opportunities for peer support, in decreasing adolescent weight status. Sixty-six adolescents with BMI >85th percentile and absolute BMI <50 were randomly assigned to the or the program. Teens in both conditions attended 16 weekly, in-person group sessions, followed by four biweekly and four monthly maintenance sessions. The enhanced condition also included weekly, group-based physical activity sessions and challenges. Group sessions were led by YMCA coaches. Groups did not differ at baseline by age (14.7 + 1.6 years), sex (60.6% female), racial/ethnic minority status (37.7%), or weight (53.0% with severe obesity). Retention was 91% at 16 weeks and 82% at 10 months. Controlling for minority status and sex, there were no significant group differences over time for BMI ( = 0.15), BMI -scores for age and sex (BMIz,  = 0.07), or percent overweight ( = 0.15). Across all participants, on average, BMI decreased by 1.4 kg/m, BMIz decreased by 0.12, and percent overweight decreased by 8.8% at four months. There were no significant differences observed in primary outcomes for adolescents randomized to the standard and enhanced versions of the program. Although the absence of a control condition precludes attribution to the intervention, teens in both conditions demonstrated greater decreases in weight status than what was observed in an open trial of the original program.