The effect of resistive exercise on resting metabolic rate, lean body weight, and percent fat during caloric restriction in obese females
Only a small number of the subjects who enter treatment For obesity maintain their target weight. Explanations for this include increased food efficiency and alterations in resting metabolic rate (RMR). The RMR has been shown to be reduced after weight reduction and it is believed that a benefit of exercise training is an adaptive increase in lean body weight (LBW) with a concurrent decrease in excess body fat. Since caloric restriction is essential for weight reduction, an increase or preservation of LBW is desirable. The purpose of this study was to assess the effect of caloric restriction (DO group; n = 6) and caloric restriction plus weight training (DWT group; n = 8} on total weight (TW), percent fat (% fat), lean body weight (LBW), and RMR during an 8 week study. Both groups met 3 days/week for 30-45 min/day to perform a specific exercise or flexibility routine. The DWT group performed three sets of ten lifts on seven resistive exercises, under supervision, while the DO group performed a set routine designed to increase flexibility but result in no appreciable exercise. Subjects met weekly with a Registered Dietitian to provide information regarding nutritional and caloric content of Food, as well as behavior modification techniques. Results revealed non-Significant treatment effects between the groups on the variables RMR, % fat, and LBW. A treatment effect was observed for TW, with the DO group significantly losing more weight. Total weight and % fat significantly decreased in both groups from pre to posttest. A significant difference was noted for the DWT group from 4 weeks - 8 weeks in RMR, although there was no effect from baseline - 8 weeks. Thus, resistive exercise when added to caloric restriction, increases strength, but results in Slower weight loss when compared to diet only subjects while resulting in similar losses in % fat and total weight.