A number of studies have shown positive effects of conjugated linoleic acid (CLA) supplementation
on body composition. Researchers reporting in the Journal of Nutrition found that CLA supplementation to obese subjects can alter body composition in as little as 12 weeks. In this study, subjects made no other lifestyle changes other than consuming either CLA or a placebo. There were 2 groups of CLA that consumed a low dose (3.2 g/day) or high dose (6.4 g/day). Body composition measured by dual energy X-ray absorptiometry revealed that subjects in the high dose CLA group had a significant increase in lean body mass of one and a half pounds, and they lost about half a pound of fat. The increase in lean body mass with CLA occurred despite no changes in diet or exercise training. The exact mechanism of how CLA increases lean body mass was not examined, but the results are consistent with some earlier reports. CLA
is naturally found in animal products such as dairy, but supplementation would be required to reach levels shown to increase lean body mass.
Steck SE, Chalecki AM, Miller P, Conway J, Austin GL, Hardin JW, Albright CD, Thuillier P. Conjugated linoleic acid supplementation for twelve weeks increases lean body mass in obese humans. J Nutr. 2007 137: 1188-1193.