INS and obesity due to melanocortin 4 receptor deficiency: Some reasons for the increase of circulating BCAA have been postulated: one is the suppression of the enzymatic catabolism of BCAAs in the adipose tissue and liver of individuals with obesity [18,19] as, in particular, the insulin-induced impairment of branched-chain α-keto acid dehydrogenase (BCKD) [20].