GIP and obesity due to melanocortin 4 receptor deficiency: Patients with obesity and T2DM undergoing Roux-en-y Gastric Bypass (RYGB) had an early improvement in glucose levels and insulin resistance, together with an increase in Glucagon-Like Peptide-1 (GLP-1) and Glucose-dependent Insulinotropic Polypeptide (GIP) a few days after surgery.3, 4, 5