The effects of conjugated linoleic acid (CLA) supplementation on body composition, strength and energy expenditure in humans when combined with resistance training

Abstract

Animal studies have demonstrated that conjugated linoleic acid (CLA) increases resting metabolic rate, enhances fatty acid oxidation, reduces body fat and increases lean tissue mass. The purpose of this study was to investigate if these beneficial effects were observed in human subjects while resistance training (3x/wk). Men and women (n=37; 18-34 yrs) were randomly assigned in a double blind fashion to supplement CLA (5.0 g/d) or placebo concurrently with seven weeks of resistance training. The following were measured before and after training: body composition (air displacement plethysmography), elbow flexors and knee extensors muscle thickness (ultrasound), strength (chest and leg press 1-RM), knee extensors and flexors isokinetic torque (isokinetic dynamometer), resting metabolic rate and respiratory exchange ratio (open circuit indirect calorimetry). The CLA group gained significantly more lean mass (2.4 kg vs. 0.8 kg, p=0.03) and combined chest and leg press strength (178 kg vs. 54 kg, p=0.05) than the placebo group. Time main effects (p