Metabolic Benefits of Prior Weight Loss with and without Exercise on Subsequent 6-Month Weight Regain

ObjectiveTo determine the 6-month follow-up effects after intentional 6-month weight loss alone (WL) and after weight loss with aerobic exercise (AEX+WL) on body composition, glucose metabolism, and cardiovascular disease risk factors in older postmenopausal women and to identify the mechanisms for weight regain. MethodsWomen (n=65, BMI>25kg/m(2)) underwent maximal oxygen consumption testing, dual-energy x-ray absorptiometry, computed tomography scans, and oral glucose tolerance tests before and after 6 months of AEX+WL or WL and at 12 months ad libitum follow-up. Insulin sensitivity (M) (hyperinsulinemic-euglycemic clamp) was measured at baseline and 6 months. Thirty WL and thirty-five AEX+WL women completed a follow-up at 12 months. ResultsSimilar weight loss was observed (-8%) in both groups from 0 to 6 months. Total fat mass, fat-free mass, visceral fat area, subcutaneous abdominal and midthigh fat areas, fasting glucose, insulin levels, homeostatic model assessment of insulin resistance (HOMA-IR), insulin areas under the curve, and triglyceride levels decreased similarly after WL and AEX+WL and remained lower at 12 months than at baseline, despite weight regain at 12 months. Initial M was associated with weight regain (r=-0.40, P<0.01). Weight regain was related to independent changes in leptin and HOMA-IR from 6 to 12 months in a multiple regression model (r=0.77, P<0.0001). ConclusionsReductions in body fat and improvements in insulin sensitivity after AEX+WL and WL were maintained at 12 months despite modest weight regain. Baseline insulin resistance partially predicted the magnitude of weight regain in postmenopausal women.