Sixty healthy obese adult volunteers will be enrolled and randomized into either: 1) placebo, 2) 3.2 g CLA, or 3) 6.4 g CLA groups and supplemented for 12 weeks. Body fat mass (BFM) and lean body mass will be determined by DEXA at baseline and twelve weeks during the intervention. In addition, indirect calorimetry will be performed at baseline and twelve weeks to measure changes in energy expenditure. The effect of CLA supplementation on weight, waist and hip measurements, and BMI will also be determined at 12 weeks. Plasma CLA and pill counts will be measured as an indication of compliance. Several blood parameters will be monitored throughout the study, and five random 24-hour recall surveys will be used to monitor dietary intake of CLA-rich foods, energy, micronutrients and antioxidants.