LAUSR

Abstract Background: Acceptance and commitment therapy (ACT) is a psychological treatment that has been found to increase weight loss in adults when combined with lifestyle modification, compared with the latter treatment alone. However, an ACT-based treatment for weight loss has never been tested in adolescents. Methods: The present pilot study assessed the feasibility and acceptability of a 16-week, group ACT-based lifestyle modification treatment for adolescents and their parents/guardians. The co-primary outcomes were: (1) mean acceptability scores from up to 8 biweekly ratings; and (2) the percentage reduction in body mass index (BMI) from baseline to week 16. The effect size for changes in cardiometabolic and psychosocial outcomes from baseline to week 16 also was examined. Results: Seven families enrolled and six completed treatment (14.3% attrition). The mean acceptability score was 8.8 for adolescents and 9.0 for parents (on a 1–10 scale), indicating high acceptability. The six adolescents who completed treatment experienced a 1.3% reduction in BMI (SD = 2.3, d = 0.54). They reported a medium increase in cognitive restraint, a small reduction in hunger, and a small increase in physical activity. They experienced small improvements in most quality of life domains and a large reduction in depression. Conclusions: These preliminary findings indicate that ACT plus lifestyle modification was a highly acceptable treatment that improved weight, cognitive restraint, hunger, physical activity, and psychosocial outcomes in adolescents with obesity.