Increases in circulating BCAAs in obesity result, in part, from decreased rates of their oxidation in adipose tissue, due to coordinated transcriptional suppression of all BCAA catabolic enzymes, as well as from increased phosphorylation and inactivation of the branched-chain ketoacid dehydrogenase (BCKDH) complex in the liver, such that fewer BCAAs are taken up from the blood.30, 42 Overall, whether BCAAs or BCAA supplementation are harmful, beneficial, or neutral requires further investigation. This evidence concerns the gene PPM1K and obesity due to melanocortin 4 receptor deficiency.