Dipeptidyl peptidase‐4 (DPP‐4) inhibitors, approved for use in T2DM,60 prevent DPP‐4 from cleaving various gut peptides including GLP‐1 and GIP22, 61; however, levels of GLP‐1 activity achieved by DPP‐4 inhibitors alone are not sufficient to stimulate a decrease in bodyweight.22, 61, 62. This evidence concerns the gene GCG and type 2 diabetes mellitus.