INS and type 2 diabetes mellitus: Observational studies on the initiation of insulin therapy in patients with T2DM have shown considerable variations in weight gain between patients,5, 6, 7, 8, 9, 10, 11, 12, 13, 14 which raises the question whether and to what part weight gain is attributable to insulin, and whether and to what part weight gain is attributable to other characteristics.