Resting energy expenditure in moderate obesity. Predicting velocity of weight loss.

The predicted resting metabolic rate (pRMR), as is estimated by the Harris-Benedict equation (HBE), was compared with the actual resting metabolic rate (mRMR), as assessed by indirect calorimetry, in 31 moderately obese (mean above ideal body weight = 44 +/- 2.8%) male subjects (mean age = 48 +/- 4.5 years; mean weight = 107.3 +/- 17.1 kg; mean% fat = 34 +/- 3.9). Measured resting metabolic rate (mRMR) (1,942 +/- 293 kcal/day) was found to be significantly (p less than 0.001) lower than pRMR (2,108 +/- 270 kcal/day), but significantly higher (p less than 0.001) than pRMR (1,636 +/- 133 kcal/day), if ideal body weight was used in the HBE formula. Individual variation of the mRMR and pRMR ranged from 65-105% and 95-155% of the expected normal population values, respectively. The findings suggest that if the reduced daily caloric needs observed are added to the metabolic suppression occurring during dietary restriction, it might explain why many obese individuals experience difficulties in maintaining predicted rates of weight loss. An equation was derived to predict RMR in moderately obese male patients.