Heshka S, Lemos T, Astbury NM, et al. - Given that resting energy expenditure (REE) and fat-free mass (FFM) reduce disproportionately following bariatric surgery-induced weight loss thereby predisposing patients to weight regain and sarcopenia, researchers compared African-American and Caucasian Roux-en-Y gastric bypass (RYGB) patients who underwent surgery with a group of non-operated controls (CON) regarding REE and body composition. The analysis revealed that compared with non-operated controls of similar anthropometrics, postbariatric surgery patients maintain a larger mass of high–metabolic rate trunk organs. REE differences were estimated with regression models adjusted for age, weight, height, ethnicity, and gender (RYGB minus CON; mean ± s.e.): year 1 (43.2 ± 34 kcal/day, p = 0.20); year 2 (− 27.9 ± 37.3 kcal/day, p = 0.46); year 5 (114.6 ± 42.3 kcal/day, p = 0.008). Following the analysis of FFM components, they observed that RYGB had greater trunk organ mass (~ 0.4 kg) and less skeletal muscle (~ 1.34 kg) than CON at each visit. No between-group differences in REE were evident when REE models adjusted for FFM, SM, trunk organs, and brain mass were applied