GIP and diabetes mellitus: Initially, the hypoglycaemic effectiveness of GIP was believed to be severely impaired in patients with type 2 diabetes mellitus (Nauck, Heimesaat, et al., 1993), with preclinical studies in animal models of diabetes revealing limited additive positive effects of combination therapy using long‐acting, enzymatically stable GIP and GLP‐1 compounds (Irwin, McClean, Cassidy, et al., 2007; Irwin, McClean, & Flatt, 2007).