To determine whether the insulin resistance can be magnified by metabolic insult, WT and Cpeb1 KO mice were fed a high fat diet (HFD) for 7 weeks, which elicited obesity in both groups of animals (whole body mass); there was also no difference in fat or lean mass between the genotypes (Figure 6B). The gene discussed is CPEB1; the disease is obesity due to melanocortin 4 receptor deficiency.