Energy Expenditure, Body Fat After Gastric Bypass Weight Loss
About Fat Loss After Bypass
| Bariatric Surgery information Energy Expenditure, Body Fat After Gastric Bypass Weight Loss |
About Fat Loss After Bypass |
| Long-Term Changes In Energy Expenditure And Body Fat Composition After Massive Weight Loss Induced By Gastric Bypass Surgery Little is known about the determinants of individual variability in body weight and fat loss after gastric bypass surgery or about the effects of massive weight loss induced by this surgery on energy requirements. The objectives were to determine changes in energy expenditure and body composition with weight loss induced by gastric bypass surgery and to identify presurgery predictors of weight loss. Method Thirty extremely obese women and men with a mean age of 39 years and a body mass index (BMI; in kg/m(2)) of 50.1 +/- 9.3 were tested longitudinally under weight-stable conditions before surgery and after weight loss and stabilization (14 +/- 2 mo). Total energy expenditure (TEE), resting energy expenditure (REE), body composition, and fasting leptin were measured. Results Subjects lost 53.2 +/- 22.2 kg body weight and had significant decreases in resting energy expenditure and total energy expenditure. Changes in REE were predicted by changes in fat-free mass and fat mass. The average physical activity level (TEE/REE) was 1.61 at both baseline and follow-up. Weight loss was predicted by baseline fat mass and BMI but not by any energy expenditure variable or leptin. Measured REE at follow-up was not significantly different from predicted REE. Conclusion Total energy expenditure and resting energy expenditure decreased by 25% on average after massive weight loss induced by gastric bypass surgery. REE changes were predicted by loss of body tissue; thus, there was no significant long-term change in energy efficiency that would independently promote weight regain. Source: Gastric Bypass Surgery to Reduce Obesity |