Glucagon-like peptide 1 (GLP-1) analogs have recently received much attention as a potential treatment for obese patients with type 2 diabetes (T2DM), and the early success of GLP-1 analogs suggests that the role of this gut peptide in the treatment of diabetes and obesity is set to expand. This evidence concerns the gene GLP1R and obesity due to melanocortin 4 receptor deficiency.