PROJECT SUMMARY/ABSTRACT
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 and bariatric surgery (MBS) reliably produces
substantial, durable weight loss and health improvements for the 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 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. We pilot-tested a one-time, group-based ACT-based workshop
intervention (+ email feedback & 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 our approach to help MBS patients boost autonomous motivation for achieving
sustainable increases in MVPA. Further, our low-touch approach makes it ideal for reducing barriers to
participation and future application in MBS and other clinical settings. We now propose to build on our 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. We will randomize 164
patients who are 10-20 months post-MBS and show relative weight stability to 12 months of: ACT targeting
autonomous motivation for MVPA; or contact-matched control (CON) providing PA-focused education and
prescribed goals. Both groups will: (1) receive two 2.5-hour group-based workshops (+ 2 booster sessions) via
Zoom video conferencing, email feedback, and telephone calls; and (2) be assessed at pre- and 3, 6, 12, and
18-months post-randomization. We will compare ACT and CON on changes in: 1) MVPA and weight regain
(primary outcomes) and 2) autonomous motivation and acceptance (secondary outcomes). We 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.
