Mechanisms for weight gain during blood glucose normalization.

Secondary failure to dietary and maximal oral treatment leads to insulin th erapy in type 2 diabetic patients. However, weight gain is a frequent side effect of insulin therapy in these patients. Mechanisms for this weight gai n are complex, insulin II reduces glycosuria and its caloric expenditure; 2 ) stimulates the stockage of fatty acids into triglycerides in adipose tiss ue, thus favoring an increase in adipose mass; 3) yields a positive nitroge n balance through an inhibition of muscle proteolysis, thus favoring an inc rease in lean mass. Most studies report an average 6 kg weight gain during the first year following the initiation of insulin therapy in type 2 diabet ic patients. Analysing body composition variations shows that weight gain r esults both from an increase in fat mass (mean 63%) and an increase in lean mass (mean 37%). Preexisiing obesity does not influence this weight gain. Finally, the 10 year-follow up of UKPDS showed a beneficial effect of insul in therapy on microangiopathy prevention, without increasing cardiovascular mortality as compared with type 2 diabetic patients on oral treatment. Thu s, while weight gain seams mandatory, it should not refrain from initiating insulin therapy in poorly controlled type 2 diabetic patients, as its expe cted beneficial effects on the prevention of microangiopathy seem well esta blished.