NORMAL LEVELS OF ENERGY-EXPENDITURE IN PATIENTS WITH REPORTED LOW METABOLISM

The present study examined the hypothesis that patients with apparent diet-resistant obesity have subnormal energy expenditure. Ten biochemi cally euthyroid patients (eight women and two men), aged 21-76 years, with either excessive gynoid fat distribution or obesity (BMI 23.8-41. 0), were referred to the department thought to be suffering from a low metabolic rate syndrome since dietary records showed very low energy intake (<5 MJ day(-1)) in combination with failure to lose weight on l ow-energy diets. Twenty-four-hour energy expenditure (24-h EE), basal energy expenditure (BEE) and sleeping energy expenditure (SEE) were me asured in a respiration chamber on a fixed activity programme. The pat ients consumed a diet containing 37 energy-per cent (E%) fat, 47 E% ca rbohydrate and 16 E% protein. The individual energy intake was estimat ed from a previously established algorithm between 24-h EE and fat-fre e mass (FFM) estimated by bioimpedance. Results were compared with equ ivalent values in a reference population of 76 subjects ranging from n ormal weight to obese. No evidence of low metabolism was found in term s of adjusted 24-h EE in the patients with diet resistance when compar ed with the control group (9263+/-819 kJ vs. 9211+/-558 kJ). No differ ences were found when comparing adjusted BEE and SEE in the two groups (7655+/-727 vs. 7411+/-770 kJ 24 h(-1) and 7048+/-672 vs. 6911+/-408 kJ 24 h(-1)). The physical activity index (PAI) during the chamber sta y was likewise within normal values (1.32+/-0.07 vs. 1.34+/-0.04; NS).