Because interaction of GLP-1 with receptors in the intestine is sufficient to activate all major responses required to impact both diabetes and obesity, it is anticipated that the administration of GLP-1 receptor agonist (GLP-1 RA) in such a way that they pass across intestinal tissue, should be an ideal method for delivering these peptides. This evidence concerns the gene GCG and obesity due to melanocortin 4 receptor deficiency.