Samocha-Bonet also examined the effect of oral L-glutamine [25 g], whole protein low in glutamine (25 g), or water on the concentration of incretin hormones and insulin response in well-controlled T2DM patients and found that the first-phase insulin response and total GLP-1 were enhanced following the ingestion of both L-glutamine and protein; however, only protein potentiated the second-phase insulin response [27]. Here, GIP is linked to type 2 diabetes mellitus.