After this BCAA-restricted diet, the T2D patients experienced improved metabolic health, as indicated by an increased oral glucose sensitivity index, increased plasma fibroblast growth factor (FGF) 21 levels, reduced meal-derived insulin secretion, and decreased mTORC1 activity with improved mitochondrial respiratory capacity in adipose tissues in comparison to those in the placebo control group. This evidence concerns the gene INS and type 2 diabetes mellitus.