Effect of impaired glucose tolerance and type II diabetes on resting metabolic rate and thermic response to a glucose meal in obese women.

We examined the hypothesis that patients with impaired glucose tolerance or type II diabetes mellitus have reduced glucose-induced thermogenesis and that this perpetuates obesity in them by reducing energy expenditure. The thermic response after a 75-g glucose meal for 150 minutes was significantly lower in five obese women with diabetes (7.18 +/- 1.8 kcal) and five other obese women with impaired glucose tolerance (6.4 +/- 0.8 kcal) than in five obese women with normal glucose tolerance (16.7 +/- 2.4 kcal) and five lean healthy control subjects (14.0 +/- 2.2 kcal, P less than 0.05). However, obese women with diabetes or impaired glucose tolerance had a significantly higher resting metabolic rate (RMR) (307.0 +/- 9.7 mL O2/min) than predicted for them on the basis of their age, body weight, and total body potassium (274.8 +/- 8.0 mL O2/min, p less than 0.01). The predicted RMR in obese women with normal glucose tolerance test (GTT) (286.0 +/- 5.0 mL O2/min) was not different from their observed RMR (272.0 +/- 6.0). Thus the total energy expenditure during the meal of obese women with diabetes (254 +/- 32 kcal/150 min) and obese women with impaired glucose tolerance (221 +/- 5 kcal/150 min) was higher than that of obese women with normal glucose tolerance (201 +/- 9 kcal/150 min). All three obese groups had a higher total energy expenditure than the lean group (158 +/- 4 kcal/150 min, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)