Resistance training in overweight women on a ketogenic diet conserved lean body mass while reducing body fat

BACKGROUND The aim of the present study was to compare the effects of 10 weeks resistance training in combination with either a regular diet (Ex) or a low carbohydrate, ketogenic diet (Lc+Ex) in overweight women on body weight and body composition. METHODS 18 untrained women between 20 and 40 years with BMI >/= 25 kg*m-2 were randomly assigned into the Ex or Lc+Ex group. Both groups performed 60-100 min of varied resistance exercise twice weekly. Dietary estimates were based on two 4-day weighed records. Body composition was estimated using Dual Energy X-ray Absorptiometry. Fasting blood samples were analyzed for total-, HDL- and LDL-cholesterol, triacylglycerols, and glucose. RESULTS 16 subjects were included in the analyses. Percentage of energy (En%) from carbohydrates, fat and protein was 6, 66, and 22 respectively in the (Lc+Ex) group and 41, 34, 17 in the Ex group. Mean weight change (pre-post) was -5.6 +/- 2.6 kg in Lc+Ex; (p < 0.001) and 0.8 +/- 1.5 kg in Ex; (p = 0.175). The Lc+Ex group lost 5.6 +/- 2.9 kg of fat mass (p = 0.001) with no significant change in lean body mass (LBM), while the Ex group gained 1.6 +/- 1.8 kg of LBM (p = 0.045) with no significant change in fat mass (p = 0.059). Fasting blood lipids and blood glucose were not significantly affected by the interventions. CONCLUSION Resistance exercise in combination with a ketogenic diet may reduce body fat without significantly changing LBM, while resistance exercise on a regular diet may increase LBM in without significantly affecting fat mass. Fasting blood lipids do not seem to be negatively influenced by the combination of resistance exercise and a low carbohydrate diet.