Increased protein catabolism secondary to insulin resistance has been suggested as possible explanation for increased BCAA in obesity.49 In moderate upper body obesity increased proteolysis and impairment of insulin's antiproteolytic action was found.50, 51 Furthermore, tissue-specific alterations in BCAA metabolism, in the liver and adipose tissue but not in muscle, may contribute to increased plasma concentrations of BCAA in obesity.49 Besides higher serum concentrations of BCAA we found lower serum concentration of PCae and lysoPC to be related with increased abdominal fat. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.