Blood glucose regulation depends on two different factors i.e. the insulin need of the body and the amount of insulin in the body. The amount of insulin, in blood, is decided by the amount of insulin infused daily, whereas the insulin need depends on the patient's weight, physical activity and diet. Overweight type 2 diabetes patients have a large insulin need and especially this need is decisive for their development of diabetes. If these patients are treated with Metformin, blood glucose decreases and the result is an easier weight loss for the patient. Especially, when these patients take this drug, the development of late diabetic complications, especially arteriosclerosis, can be avoided or postponed.