Effects of Resistance Training With or Without Protein Supplementation on Body Composition and Resting Energy Expenditure in Patients 2–7 Years PostRoux-en-Y Gastric Bypass: a Controlled Clinical Trial

Background Resistance training (RT) and adequate protein intake are recommended as strategies to preserve fat-free mass (FFM) and resting metabolic demand after bariatric surgery. However, the effect of both interventions combined in the late postoperative period is unclear. This study investigated the effects of RT, isolated and combined with protein supplementation, on body composition and resting energy expenditure (REE) in the late postoperative period of Roux-en-Y gastric bypass (RYGB). Methods This controlled trial involved patients who were 2–7 years postRYGB. Participants were partially matched on body mass index (BMI), age, sex, and years after surgery, and divided into four groups, placebo maltodextrin (control [CON]; n = 17), whey protein supplementation (PRO; n = 18), RT combined with placebo (RTP; n = 13), and RT combined with whey protein supplementation (RTP + PRO; n = 15)—considering the participants who completed the protocol. REE was measured by indirect calorimetry and body composition by multifrequency electrical bioimpedance. Results Participant characteristics (40.3 ± 8.3 years old; average BMI 29.7 ± 5.3 kg/m 2 ; 88.9% females) were similar among groups. The RTP+PRO group showed an increase of 1.46 ± 1.02 kg in FFM and 0.91 ± 0.64 kg in skeletal muscle mass (SMM), which was greater than the equivalent values in the CON group (− 0.24 ± 1.64 kg, p = 0.006 and − 0.08 ± 0.96 kg, p = 0.008, respectively). There was no significant time-by-group interaction for absolute or relative REE. Conclusion Combined RT and adequate protein intake via supplementation can increase FFM and SMM in the late postoperative period without changing REE. These associated strategies were effective in improving muscle-related parameters and potentially in improving the patients’ physical function.