Notably, C57BL/6J mice that are maintained on an HFD develop obesity [52,53,77,80,111,112,113,114,115,116,117,118,119,120,121,122,123] as glucose tolerance is impaired and insulin resistance results in elevated blood glucose and insulin levels [81,117,118,119,120,121,123,124]. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.