In comparison with normal weight controls, previous studies on duodenal GLP‐1 cell numbers in T2D or obesity are not conclusive, as both increase (Theodorakis et al., 2006), no differences (Jorsal et al., 2018) or decrease (Wölnerhanssen et al., 2017) have been reported (Table 1). Here, GCG is linked to obesity due to melanocortin 4 receptor deficiency.