ABSTRACT
Background: Obesity prevalence among adolescent girls continues to rise. Acceptance-based therapy (ABT) is effective for weight loss in adults and feasible and acceptable for weight loss among adolescents. This pilot randomized controlled trial (RCT) assessed effectiveness of an adolescent-tailored ABT intervention on decreasing weight-related outcomes and improving psychological outcomes compared with enhanced care. Methods: In this 6-month, two-arm pilot RCT, participants were randomized to the ABT intervention or to enhanced care. The ABT intervention condition attended 15 virtual, 90-minute group sessions. The enhanced care comparison received 15 healthy lifestyle handouts and virtually met twice with a registered dietitian. The primary outcome assessed was change in BMI expressed as a percentage of the 95th percentile (%BMIp95). Results: Participants included 40 girls (ages 14-19) assigned to ABT (n = 20) or enhanced care (n = 20). A decrease in %BMIp95 was observed within the ABT intervention [d = -0.19, 95% confidence interval, CI: (-0.36 to -0.02)], however, not within the enhanced care comparison [d = -0.01, 95% CI: (-0.09 to 0.07)]. The ABT group showed slight changes in psychological flexibility [d = -0.34, 95% CI: (-0.62 to -0.06)] over enhanced care [d = -0.11, 95% CI: (-0.58 to 0.37)]. There was no significant intervention effect noted between groups. Conclusion: In this pilot RCT, the ABT intervention was as effective as enhanced care for weight loss. However, previous ABT studies occurred in person, and this study was conducted virtually due to COVID-19. Thus, future research investigating the potential effectiveness of ABT in-person among adolescents and optimization of virtual interventions is needed.