Sutton et al. demonstrated that obesity associated with MC3R deficiency is dependent on the dietary fat, considering that, if exposed to a low-fat diet, MC3R KO mice exhibited a modest increase in adiposity and a normal body weight, while during a high-fat diet, fat mass was comparable to that of MC4R KO littermates [68]. Here, MC3R is linked to obesity due to melanocortin 4 receptor deficiency.