Energy requirements and energy expenditure of lean and overweight women, measured by indirect calorimetry.

To estimate the energy requirement of lean and overweight women, 29 lean (body weight, 59 +/- 1 kg; means +/- SEM) and 18 overweight (94 +/- 5 kg) women consumed a weight-maintenance diet for 8 d. The final 80 h were spent in a whole-body indirect calorimeter. Actual metabolizable energy intake (ME) was measured by analyzing food, feces, and urine. Mean ME was 8.88 +/- 0.13 MJ/d (2123 +/- 30 kcal/d) (lean) and 10.12 +/- 0.29 MJ/d (2419 +/- 70 kcal/d) (overweight). Mean 24-h energy expenditure (24hEE) of the lean (8.58 +/- 0.13 MJ or 2052 +/- 32 kcal) was lower than that of the overweight (10.70 +/- 0.45 MJ or 2558 +/- 108 kcal; p less than 0.001) women. Energy balance was close to zero in both groups. Therefore, 24hEE was used as an estimation of energy requirement. Multiple-regression analysis showed body weight to be the best single predictor of 24hEE. Our data may be useful for prediction of energy requirements of women (aged 20-50 yr) in normal life.