Branching chain amino acids (BCAA) have both beneficial and detrimental effects of on metabolism have been established and therefore warrants further investigation. In the preliminary study, the investigators found that BCAAs enhanced glucose metabolism in lean mice while they promoted glucose intolerance in obese mice. In lean mice, BCAAs decreased adiposity and enhanced glucose utilization and insulin sensitivity in different tissues. But in obese mice, BCAAs' effects were mediated by impaired insulin signaling in fat tissue.