The relationship between insulin sensitivity and weight reduction in simple obese and obese diabetic patients.

Tissue sensitivity to exogenous insulin was determined in 10 obese diabetic patients, in 15 patients with simple obesity, and in 28 non-obese controls. Eight of the obese diabetics and five of the patients with simple obesity underwent dietary restriction (1,000-1,600 kcal/day) and physical training for eight weeks. Insulin sensitivity was evaluated by the euglycemic insulin clamp technique for 120 min. The amount of infused glucose (glucose mctabolism: GM) is a measure of the overall tissue sensitivity to insulin. Differences in fasting blood glucose levels were adjusted by calculation of the glucose metabolic clearance rate (MCR). GM and MCR in the obese diabetics and in the patients with simple obesity were significantly (P<0.001) lower than in the controls. Inverse correlations existed between BMI and GM, between BMI and MCR, and also between fasting plasma insulin levels and both GM and MCR, respectively. After physical training, significant weight reduction was obtained, while MCR increased from 2.70 ± 0.26 ml/kg/min to 5.47 ± 0.88 ml/kg/min. Further significant correlation existed between reduction of BMI and increases in insulin sensitivity (GM and MCR). These results suggest that a combined program of physical training with caloric restriction would decrease body weight and increase peripheral insulin sensitivity, and would therefore be especially appropriate for the treatment of simple obese and obese diabetic patients.