MTOR and type 2 diabetes mellitus: Three potential mechanisms for how BCAAs lead to the occurrence of T2DM are: First, increased levels of BCAAs can result in the accumulation of toxic metabolites, which in turn causes mitochondrial dysfunction and a decrease in secretion of insulin in pancreatic beta cells (18, 19); second, perturbations of BCAAs can induce insulin resistance through the mTOR signaling pathway (20); third, increased levels of BCAAs can activate the rapamycin pathway, which then disturb the action of insulin and promote the degradation of insulin receptor substrates (21, 22).