On the other hand, we previously reported that both wild-type (WT) and GIP receptor-deficient (GiprKO) mice fed a high-starch, low-protein diet (HSTD), show a body weight gain, compared with those fed normal chow (NC), indicating that HSTD induces obesity in a manner independent of the GIP signal [5]. This evidence concerns the gene GIP and obesity due to melanocortin 4 receptor deficiency.