A Multi-Site Study of Brief Cognitive-Behavioural Therapy for Eating Disorders for Individuals With BMI ≥ 30

Abstract

Objective: Cognitive-behavioural therapy (CBT) for eating disorders (EDs) has raised concerns of appropriateness for patients in higher-weight bodies. We evaluated acceptability (Sample 1—United States [USA]) and effectiveness (Sample 1—USA, Sample 2—United Kingdom [UK]) of CBT-T by body mass index [BMI] category. We hypothesised that individuals with BMI ≥ 30 kg/m2 would be more likely to drop out and show smaller symptom reductions compared to participants with BMI < 30 kg/m2. Methods: Participants with non-underweight EDs (USA: n = 63; UK: n = 58) received CBT-T and completed the ED-15 to evaluate change in behaviours (objective binge eating, purging, restriction, excessive exercise) and cognitions (Eating Concern, Weight/Shape Concern, Global Score). Results: Contrary to hypotheses, CBT-T completion did not differ by BMI category. Participants demonstrated large and significant reductions in binge eating, excessive exercise, and ED cognitions, with no significant differences by BMI (USA, UK). Although the BMI ≥ 30 kg/m2 group demonstrated significantly smaller reductions in restriction and purging (UK only), smaller reductions in the higher-weight group were fully explained by their significantly lower pre-treatment symptoms. Discussion: Results from this exploratory multisite study found no evidence that CBT-T was less acceptable or effective for participants in higher-weight bodies.