Exercise reprograms the gut microbiota to enhance metabolic outcomes after bariatric surgery: a translational,...

Exercise training has been associated with metabolic improvements in bariatric patients beyond weight and fat loss, potentially involving modulation of the gut microbiota. We investigated whether exercise-related microbial changes are associated with metabolic adaptations in women undergoing Roux-en-Y gastric bypass (RYGB) by combining a randomized controlled exercise intervention trial in women post-surgery with a human-to-mouse fecal microbiota transplantation (FMT) experiment.

Thirty-two women were randomized to RYGB (n = 16) or RYGB plus a 6-month exercise training program initiated three months post-surgery (RYGB + ET; n = 16), while a lean control group (LEAN; n = 16) was evaluated at baseline. Blood and fecal samples were collected before surgery, and at 3 (POST3) and 9 (POST9) months following surgery for biochemical, inflammatory, and microbiota analyses.

Both surgical groups showed comparable improvements in body composition and inflammation; however, RYGB + ET was associated with greater improvements in HDL, triglycerides, fasting glucose, and fasting insulin. Exercise was also associated with increased gut microbiota α-diversity and shifts in microbial composition, including enrichment of genera previously linked to short-chain fatty acid (SCFA) metabolism and host metabolic health. To explore the potential contribution of these microbial communities, fecal microbiota collected at POST9 were transplanted into 36 high-fat diet-fed female mice, generating recipient groups rRYGB, rRYGB+ET, and rLEAN. Mice receiving RYGB + ET microbiota displayed similar inflammatory status and glucose tolerance, but lower fasting insulin and HOMA-IR, along with partial preservation of intestinal morphology, compared with mice receiving RYGB microbiota.

These findings suggest that exercise following bariatric surgery is associated with distinct gut microbial configurations and metabolic improvements, and that exercise-conditioned microbiota may contribute to aspects of host metabolic regulation after surgery.