The approval of incretin-based therapies, including the glucagon-like peptide-1 (GLP1) receptor agonists Liraglutide [11] and Semaglutide [12], and the glucose-dependent insulinotropic polypeptide (GIP) and GLP1 dual agonist Tirzepatide [13], has brought new hope for the medical management of obesity. The gene discussed is GIP; the disease is obesity due to melanocortin 4 receptor deficiency.