Motivating Increases in Physical Activity for Prevention of Weight Regain After Metabolic Bariatric Surgery

Nearly one in five U.S. adults have severe obesity (Body Mass Index ≥ 35 kg/m2), which is related to numerous comorbidities and reduced life expectancy. Metabolic bariatric surgery (MBS) reliably produces substantial, durable weight loss and health improvements for a majority of patients with severe obesity. However, weight regain over time is common and can develop into a serious complication marked by reemergence of comorbidities and impaired physical and mental quality of life. This issue is compounded by a lack of effective and accessible strategies to help MBS patients prevent weight regain and achieve lifelong success. Indeed, current post-surgical guidelines advise that patients increase moderate-to-vigorous intensity physical activity (MVPA) for weight loss maintenance and lifelong health, but most patients do not, and available interventions do not address their reported low internal drive to engage in regular MVPA. Acceptance and Commitment Therapy (ACT)-based interventions are effective at promoting health behavior changes via improved autonomous (or internal) motivation. ACT achieves this by clarifying personal values, linking behavioral performance to those values, and increasing acceptance of contrary thoughts and emotions that act as barriers to new behavior engagement. The investigators pilot-tested a one-time, group-based ACT-based workshop intervention (+ email feedback and support phone calls) to increase MVPA among low-active adults with obesity. Participants on average achieved and maintained clinically important increases in MVPA and autonomous motivation, and larger improvements in motivation were related to larger MVPA increases. These preliminary results show potential for this approach to help MBS patients boost autonomous motivation for achieving sustainable increases in MVPA. Further, this low-touch approach makes it ideal for reducing barriers to participation and future application in MBS and other clinical settings. The investigators will now build on these findings by testing whether targeting MBS patients' autonomous motivation with ACT-based intervention produces sustained increases in MVPA, and if such increases prevent weight regain after MBS. The investigators will randomize 164 patients who are 8-20 months post-MBS and show relative weight stability to 12 months of: ACT targeting autonomous motivation for MVPA; or contact-matched educational control (CON) providing PA-focused education and prescribed goals. Both groups will: (1) receive group-based workshops via Zoom video conferencing, email feedback and homework assignments, and individual telephone counseling calls; and (2) be assessed at pre- and 3, 6, 12, and 18-months post-randomization. The investigators will compare ACT and CON on changes in: 1) MVPA and weight regain (primary outcomes) and 2) autonomous motivation and acceptance (secondary outcomes). The investigators will also explore mediators of the treatment effect on MVPA (motivation, acceptance) and weight regain (MVPA). If successful, results could justify more robust physical activity guidelines and use of these strategies in clinical practice to help motivate MBS patients to achieve sustainable increases in MVPA for weight regain prevention.