GCG and obesity due to melanocortin 4 receptor deficiency: Another important limitation to ourstudy is that the associations between fasting GLP-1 and glycemic status, insulinsensitivity, obesity, and diet do not assess causality, temporality with progression ofdiabetes, or physiological role of fasting GLP-1 in terms of GLP-1 active(7,36):inactivemetabolite(9,36) plasma levels.