Normal thermic effect of glucose in obese women.

The increase in energy expenditure after intake of 100 g of glucose (thermic effect of glucose), was studied in 11 lean and 13 obese women. Before glucose ingestion, resting metabolic rate, uncorrected for weight or surface area, was 15% higher in the obese subjects than in the lean subjects, but there was no difference between groups in the thermic effect of glucose. The obese subjects were hyperinsulinemic relative to the lean subjects, but the area under their glucose response curves was normal. The increase in norepinephrine levels associated with glucose intake was the same in the obese and lean groups. The magnitude of the thermic effect of glucose was not correlated with the increase in plasma norepinephrine levels, plasma insulin levels, or pulse rate, or with body weight, age or body mass index. Resting metabolic rate did not significantly increase in 10 subjects given a noncaloric control solution. These data show that obese subjects with normal glucose tolerance have a normal thermic response to glucose.