Are there any differences between women with long term gastric bypasses and non-operated matched controls in body composition, muscular strength and physical performance?

Introduction: There is concern about an excessive loss of fat-free mass (FFM), and its consequences in the long term after bariatric surgery. The aim of this study was to evaluate body composition, muscle strength and physical performance in a group of women who underwent Roux-en-Y Gastric Bypass (RYGB-G) more than 2 years ago, and had stable weight, not significant weight regain, using micronutrient supplementation and compare them with a non-operated control group (CG). Methods We assessed body composition by DEXA, handgrip strength (HGS) and physical performance through sit-to-stand tests in the RYGB-G (n = 13) and in a CG (n = 13) matched by age, body mass index, skin phototype and physical activity level. Dietary intake, sun exposure, nutritional, biochemical and hormonal assessments were done in both groups. Results The RYGB-G had a mean follow-up of 6.7 ± 2.8 years and had a greater FFM (42.3 ± 4.9 vs 38.4 ± 4.5kg, p = 0.049), FFM% (60.7 ± 5.1 vs 56.1 ± 5.1%, p = 0.027) and FFM/Fat Mass (1.72 ± 0.43 vs 1.39 ± 0.30kg, p = 0.033) than the CG. The CG had a higher fat mass percentage (FM% 36.4 ± 5.2 vs 41.1 ± 5.3%, p = 0.029). There were no differences between the groups for HGS or physical performance tests. The average energy intake was significantly higher in the CG 1021.5 (957.5-1278.7) vs 1498.6 (1310.7-1767.7) kcal/day p = 0.002. Conclusion Women with a long term RYGB (BMI 27.5 ± 3.4 kg/m ² ) and regular use of micronutrients supplementation had a higher FFM, FFM%, FFM/FM and lower FM% compared to a CG, without differences in HGS or physical performance tests.