To examine associations of objectively-measured physical activity (PA) with changes in weight after Roux-en-Y gastric bypass (RYGB) over 7 years.
The contribution of free-living PA to surgery-induced weight loss and subsequent weight regain is not well understood.
Participants of a multi-center prospective cohort study of bariatric surgery were followed annually ≥7 years. Of 807 participants who underwent RYGB and were given an activity monitor, 649 (80%) had sufficient data for this report (78% female; median age 47 years; median body mass index 46 kg/m2). Mean daily steps, hours/day in sedentary behavior (SB) and minutes/week in moderate-to-vigorous physical activity (MVPA) were determined at each assessment. Mixed models tested associations between PA measures and weight outcomes, controlling for sociodemographics, health status and eating behaviors.
Across follow-up, mean pre- to post-surgery changes in PA were small, and mean post-surgery PA level was below PA recommendations for health (e.g., 101 MVPA min/week 7 years post-surgery versus the ≥150 MVPA min/week recommendation). There was a dose-response association between more steps, less SB and more MVPA with greater weight loss. Steps and SB, but not MVPA, were also associated with weight regain. For example, participants in the highest versus lowest steps quartile lost 2.9% (95%CI, 1.8–4.1) more of their pre-surgery weight and regained 5.4% (95%CI, 2.4–8.3) less of their maximum weight lost across follow-up.
Despite only small increases in objectively-measured PA level after RYGB, PA level was independently associated with weight outcomes of bariatric surgery throughout 7 years of follow-up.
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