GLP1R and type 2 diabetes mellitus: Patients with T2DM who take hypoglycaemic drugs (e.g. insulin, glucagon-like peptide 1 (GLP-1) receptor agonists, sodium-glucose cotransporter 2 (SGLT2) inhibitors and sulphonylureas but NOT metformin or GLP-1 agonists [178] should be particularly cautious when considering the ketogenic diet.