Motivating increases in physical activity to prevent recurrence of weight gain after metabolic bariatric surgery: The Exercise Values of Life and Vitality Everyday (EVOLVE) trial.

BACKGROUND: Recurrence of significant weight gain after metabolic and bariatric surgery (MBS) is common and can lead to physical and psychological complications. Although patients are encouraged to increase moderate-to-vigorous intensity physical activity (MVPA) to prevent weight recurrence, many report low motivation. This study tests whether targeting autonomous motivation through an Acceptance and Commitment Therapy (ACT)-based intervention can produce durable increases in MVPA to prevent postoperative weight recurrence. STUDY DESIGN: A total of 164 adults who are 6-20 months post-MBS with stable weight (<10 % regain from maximum weight loss) are randomly assigned to one of two 12 months programs: an ACT intervention (Physical Activity [PA]-ACT) or a contact-matched education control (PA-EDU). PA-ACT uses values clarification and acceptance strategies to foster autonomous motivation for self-determined MVPA goals. PA-EDU provides didactic instruction on PA, related health topics, and cognitive-behavioral strategies for prescribed MVPA goals. Both conditions receive group-based workshops and individual counseling delivered via video conferencing and email micro-interventions. The conditions will be compared on changes in MVPA and weight recurrence (primary outcomes) and autonomous motivation and acceptance (secondary outcomes) from baseline to 12 months (end-of-treatment) and 18 months (follow-up). Mediators of MVPA (motivation, acceptance) and weight recurrence (MVPA) will also be explored. CONCLUSION: This is the first study to examine whether an ACT-based intervention can foster autonomous motivation for sustained MVPA to prevent weight recurrence after MBS. The results may inform more robust guidelines for PA in MBS and support integration of these strategies into clinical practice to prevent significant weight recurrence. CLINICALTRIALS: govRegistration: NCT037604.