REAPPRAISAL OF THE RESTING METABOLIC-RATE OF NORMAL YOUNG MEN

The Harris-Benedict (HB) equation, widely used to estimate the resting metabolic rate (RMR), has been disputed by Owen et al who reported that it overestimates the RMR of men aged < 50 y by approximately 9%. We measured the RMR of 29 healthy, nonsmoking men aged 18-33 y by direct oxygen consumption with a closed-circuit technique similar to that used by Harris and Benedict (respirometer), as well as by a ventilated-hood technique. RMR determined by the ventilated-hood technique was 5.6% lower than when determined by the respirometer (1643 +/- 148 vs 1721 +/- 145 kcal/d, respectively, xBAR +/- SD; P < 0.001). RMRs by both these methods were lower than the value of 1813 +/- 164 kcal/d predicted by the HB equation; the 95% confidence intervals (CIs) for RMR were 92.4-98.1% (respirometer) and 88.5-91.1% (ventilated hood) of the value predicted by the HB equation. The 95% Cl for RMR determined by ventilated hood was 98.4-103.5% of the value predicted by using a new equation proposed by Owen et al. We conclude that the HB equation overestimates RMR by 9.2% in normal young men. This could be due in part to the inherent discomfort experienced by subjects when the original technique was used.