INS and Insulin resistance: Patients with insulin resistance, characterised clinically by a raised BMI (>30 kg/m2), compared with non-obese patients will: (i) respond well to pioglitazone, a thiazolidinedione that works as an insulin sensitiser13; (ii) respond less well to sitagliptin, a DPP4 inhibitor which works through stimulating endogenous insulin secretion post-prandially.14