In addition to remission of diabetes, subjects in a non-randomized, prospective cohort study showed decreased glucose, insulin, and leptin levels within 3 months of surgery, and glucagon-like peptide 1 (GLP-1), glucose-sensitive insulinotropic peptide (GIP), peptide-YY, while pancreatic polypeptide concentrations increased within days (4, 5, 24), On the contrary, fasting did not affect high molecular weight adiponectin, ghrelin, leptin, or GLP-1, suggesting unique effects of surgery compared to diet (20). Here, GCG is linked to diabetes mellitus.