ACTonFood. Acceptance and Commitment Therapy-Based Group Treatment Compared to Cognitive Behavioral Therapy-Based Group Treatment for Weight Maintenance: An Individually Randomized Group Treatment Trial

The purpose of this Individually Randomized Group Treatment Trial was to compare an Acceptance and Commitment Therapy-based (ACT) group intervention and a Cog-nitive Behavioral Therapy-based (CBT) group intervention for weight loss maintenance in a sample of adult patients with obesity seeking treatment for weight loss. 155 over-weight adults (BMI: Kg/m2= 43.8[6.8]) attending a multidisciplinary rehabilitation program for weight loss were randomized into two conditions: ACT and CBT. Demo-graphical, physical, and clinical data were assessed at the beginning of the program (t0), at discharge (t1), and at 6-month follow-up (t2). The following measures were ad-ministered: The Acceptance and Action Questionnaire-II (AAQ-II) and the Clinical Outcome in Routine Evaluation-Outcome Measure (CORE-OM). Generalized linear mixed models were performed to assess differences between groups. Moderation ef-fects for gender and eating disorders (ED) have been considered. From baseline to dis-charge no significant differences between interventions were found, with the only ex-ception of an improvement in the CORE-OM total score and in the CORE-OM subjective well-being subscale for those in the CBT condition. From discharge to follow-up ACT group participants showed significant results in terms of weight loss maintenance, CORE-OM total score, and CORE-OM and AAQ-II’s wellbeing, symptoms, and psy-chological problems subscales. Gender moderated the effects of time and intervention on the CORE-OM’ subscale reporting the risk for self-harm or harm others. The pres-ence of an eating disorder moderated the effect of time and intervention on the CORE-OM total score, on the CORE-Om’ symptoms and psychological problems sub-scales, and on the AAQ-II. Patients who received the ACT intervention were more likely to achieve a ≥5% weight loss from baseline to follow-up and to maintain the weight loss after discharge. The ACT intervention was thus effective in maintaining weight loss over time.