Carbohydrate Restriction and Resistance Training Have Additive Effects on Body Composition during Weight Loss in Men

Abstract

Text: Low carbohydrate diets are more effective than low fat diets for inducing weight and fat loss, but there is often greater loss in lean body mass as well. Resistance training is a powerful stimulus for muscle hypertrophy so we hypothesized that a combination of carbohydrate reduction and heavy resistance training would result in optimal changes in body composition. Fifty healthy, overweight/obese men (mean SEM: age 31 1.5y; body weight 100.3 2.0kg; BMI 32.0kg m; %fat mass 33.1 0.8%) were placed into a low fat diet (LFD) group that restricted fat to less than 25% of energy or a very low carbohydrate ketogenic diet (VLCKD) group that reduced carbohydrate to less than 15% energy. Two additional groups performed a periodized resistance exercise program 3 times/wk while consuming either the low fat (LFDRE) or low carbohydrate (VLCKD-RE) diet. Weight loss and body composition by dual-energy X-ray absorptiometry were determined before and after 12 wk. Weight loss was nearly two-fold greater in subjects consuming the VLCKD ( 10.1kg) than the LFD ( 5.5kg), and both groups experienced significant losses in fat mass and lean body mass. Resistance training reduced the magnitude of weight loss, but resulted in increased lean body mass without compromising fat loss in both diet groups. The most dramatic reduction in percent body fat was in VLCKD-RE ( 5.3%), followed by LFD-RE ( 3.5%), VLCKD ( 3.4%), and LFD ( 2.0%). These data show for the first time that resistance training is a potent stimulus to protect lean body mass in men consuming a low carbohydrate diet, while still allowing for significantly greater fat loss.