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Introduction: Bariatric surgery-induced weight loss may reduce resting energy expenditure (REE) and fat-free mass (FFM) disproportionately thereby predisposing patients to weight regain and sarcopenia., Methods: We compared REE and body composition of African-American and Caucasian Roux-en-Y gastric bypass (RYGB) patients after surgery with a group of non-operated controls (CON). REE by indirect calorimetry; skeletal muscle (SM), trunk organs, and brain volumes by MRI; and FFM by DXA were measured at post-surgery visits and compared with CON (N = 84) using linear regression models that adjusted for relevant covariates. Ns in RYGB were 50, 42, and 30 for anthropometry and 39, 27, 17 for MRI body composition at years 1, 2, and 5 after surgery, respectively., Results: Regression models adjusted for age, weight, height, ethnicity, and sex showed REE differences (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). Analysis of FFM components showed that RYGB had greater trunk organ mass (~ 0.4 kg) and less SM (~ 1.34 kg) than CON at each visit. REE models adjusted for FFM, SM, trunk organs, and brain mass showed no between-group differences in REE (- 15.9 ± 54.8 kcal/day, p = 0.8; - 46.9 ± 64.9 kcal/day, p = 0.47; 47.7 ± 83.0 kcal/day, p = 0.57, at years 1, 2, and 5, respectively)., Conclusions: Post bariatric surgery patients maintain a larger mass of high-metabolic rate trunk organs than non-operated controls of similar anthropometrics. Interpreting REE changes after weight loss requires an accurate understanding of fat-free mass composition at both the organ and tissue levels., Clinical Trial Registration: Long-term Effects of Bariatric Surgery (LABS-2) NCT00465829.

Objective: This study investigated changes in fat-free mass (FFM) and skeletal muscle 5 years after surgery in participants from the Longitudinal Assessment of Bariatric Surgery-2 trial., Methods: A three-compartment model assessed FFM, and whole-body magnetic resonance imaging (MRI) quantified skeletal muscle mass prior to surgery (T0) and 1 year (T1), 2 years (T2), and 5 years (T5) postoperatively in 93 patients (85% female; 68% Caucasian; age 44.2 ± 11.6 years) who underwent gastric bypass (RYGB), sleeve gastrectomy, or adjustable gastric band. Repeated-measures mixed models were used to analyze the data., Results: Significant weight loss occurred across all surgical groups in females from T0 to T1. FFM loss from T0 to T1 was greater after RYGB (mean ± SE: -6.9 ± 0.6 kg) than adjustable gastric band (-3.5 ± 1.4 kg; P < 0.05). Females with RYGB continued to lose FFM (-3.3 ± 0.7 kg; P < 0.001) from T1 to T5. A subset of males and females with RYGB and MRI-measured skeletal muscle showed similar initial FFM loss while maintaining FFM and skeletal muscle from T1 to T5., Conclusions: Between 1 and 5 years following common bariatric procedures, FFM and skeletal muscle are maintained or decrease minimally. The changes observed in FFM and muscle during the follow-up phase may be consistent with aging., (© 2018 The Obesity Society.)

Background: A paucity of information is available on the comparative body composition changes after bariatric procedures. The present study reports on the body mass index (BMI) and body composition changes after 4 procedures by a single group., Methods: At the initial consultation, the weight and body composition of the patients undergoing 4 different bariatric procedures were measured by bioimpedance (Tanita 310). Follow-up examinations were performed at 1 year and at subsequent visits after surgery. Analysis of variance was used to compare the postprocedure BMI and body composition. Analysis of covariance was used to adjust for baseline differences., Results: A total of 101 gastric bypass (GB) patients were evaluated at 19.1 + or - 10.6 months, 49 biliopancreatic diversion with the duodenal switch (BPD/DS) patients at 27.5 + or - 16.3 months, 41 adjustable gastric band (AGB) patients at 21.4 + or - 9.2 months, and 30 sleeve gastrectomy (SG) patients at 16.7 + or - 5.6 months (P <.0001). No differences were found in patient age or gender among the 4 groups. The mean preoperative BMI was significantly different among the 4 groups (P <.0001): 61.4 kg/m(2), 53.2, 46.7, and 44.3 kg/m(2) for the SG, BPD/DS, GB, and AGB group, respectively. The postoperative BMI adjusted for baseline differences was 27.8 (difference 23.6 + or - 8.3), 32.5 (difference 15.6 + or - 5.0), 37.2 (difference 18.2 + or - 8.2), and 39.5 kg/m(2) (difference 7.5 + or - 4.3) for the BPD/DS, GB, SG, and AGB groups, respectively (P <.0001). The percentage of excess weight loss was 84%, 70%, 49%, and 38% for the BPD/DS, GB, SG, and AGB groups, respectively (P <.0001). The postoperative percentage of body fat adjusted for baseline differences was 25.7% (23.9% + or - 7.0%) 32.7% (16.1% + or - 10.5%) 37.7% (16.7% + or - 5.6%), and 42% (6.0% + or - 6.8%) for the BPD/DS, GB, SG, and AGB groups, respectively (P <.0001). The lean body mass changes were reciprocal., Conclusion: Although the BPD/DS procedure reduced the BMI the most effectively and promoted fat loss, all the procedures produced weight loss. The AGB procedure resulted in less body fat loss within 21.5 months than SG within 16.7 months. Longer term observation is indicated.

Objective: As the acceptance of surgical procedures for weight loss in morbid obesity is increasing, clinically useful baseline and follow-up measures of total body water (TBW) and resting energy expenditure (REE) are important. Research methods such as deuterium (D(2)O) dilution and metabolic carts are problematic in the clinical setting. We compared bioimpedance analysis (BIA) predicted (Tanita TBF-310) and measured TBW and REE., Methods and Procedures: Forty-two paired presurgery studies were completed using BIA and D(2)O in patients with BMI (mean +/- s.d.) 50.2 +/- 8.8 kg/m(2) for TBW, and 30 patients with BMI 51.0 +/- 13 kg/m(2) completed paired determinations of REE with metabolic carts and the Tanita balance with weight, height, sex, and age modifiers. Regression analysis and Bland-Altman plots were applied., Results: When regression analysis was completed for TBW, regression line was consistent with the identity line "y = x." The intercept was not different from 0 (95% confidence interval -2.5 +/- 7.0). The slope of the line was not different from 1.0 +/- 0.1. The measured TBW 51.2 +/- 10.1 l had a correlation with the predicted 49.5 +/- 11.27 l of 0.92. There also was no significant difference (P = 0.33) between predicted (2,316 +/- 559 kcal/day) and measured REE (2,383 +/- 576 kcal/day);delta 66.7 +/- 273 kcal/day. The two measures were highly correlated (r = 0.88) with no bias detected., Discussion: These observations support the use of the BIA system calibration in subjects with severe obesity. Without the use of complex, costly equipment and invasive procedures, BIA measurements can easily be obtained in clinical practice to monitor patient responses to treatment.

Abstract: Background: Differences in excess weight loss, body mass index (BMI) change, and body composition have been related to different types of bariatric procedures. Our objective was to explore these alterations related to body mass in superobese (SO) and morbidly obese (MO) patients in a university hospital setting. Methods: Patients provided written informed consent and had their body composition measured before and after surgery using bioimpedance (Tanita 310). The t test was used to compare MO and SO. Pearson''s correlations were used to examine the BMI, excessive BMI loss, percentage of body fat (BF) change, and fat-free mass. Results: A total of 133 MO patients had a BMI of 43.3 kg/m2 and 88 SO patients had a BMI of 59.4 kg/m2. The percentage of BF was 46.7% and 51.9% (P < .0001). The differences in the follow-up period after surgery (21.5 and 20.6 months; P = .62) and patient age (43.4 and 42.5 yr) were not significant, but the gender distribution was significant (P = .003). After surgery, the MO patients had a BMI of 30.9 ± 5.7 kg/m2 and the SO patients had a BMI of 37.3 ± 9.0 kg/m2. The percentage of BF was not different between the 2 groups (MO, 33.1% ± 9.6% and SO, 35.0% ± 12.4%; P = .21). Gender differences in the percentage of BF were present before surgery; however, after surgery, these were absent for the men in the 2 groups (24.8% and 26.6%; P = .51). The change in the BMI and the change in the BF had a stronger correlation for the MO patients (r = .83 versus r = .53) than for the SO patients. The fat-free mass loss correlated with the change in BMI without regard to procedure. The percentage of excessive BMI loss was 65.1% for the MO and 63.4% for the SO patients (P = .64). Conclusions: The SO patients achieved excessive BMI loss similar to that of the MO patients, with more SO men choosing biliopancreatic diversion/duodenal switch. At a BMI of 37.3 kg/m2, the SO patients had a percentage of BF that was not different from that of the MO patients at 30.9 kg/m2. The fat-free mass losses correlated with the change in BMI. [Copyright &y& Elsevier]