The relationship between branched-chain amino acids (BCAAs) and obesity has been reported to involve various intertwined players, including higher dietary intake, abnormal transporter expression, IR-triggered blunted capacity of insulin to inhibit proteolysis, and overflow to skeletal muscle as a result of impaired catabolism in adipose tissue, which ultimately lead to the accumulation of BCAAs and by-products (e.g., α-ketoacids, short-chain acyl-carnitines, peptides) in blood [24]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.