Predicted and measured resting metabolic rate in young, non-obese women

Measured resting metabolic rate (RMR) was compared with predicted RMR in a sample of young, non-obese women.

In 52 women aged 19 to 30 with a body mass index of 16 to 29 kg/m2, RMR was measured with a MedGem indirect calorimeter and predicted with five commonly used equations: the Harris-Benedict (1919), Mifflin (1989), Owen (1985), Schofield (weight) (1985), and Schofield (weight and height) (1985) equations. Measured RMR and predicted RMR were compared through the use of various measures.

In comparison with the measured RMR, the RMR predicted with four of the five equations was significantly higher (by 16 to 225 kcal/day, p < 0.001). At the group level, the Owen equation performed best and captured the greatest proportion of individuals (65%) for whom predicted RMR differed from measured RMR by less than 10%. With the other four equations, residuals exceeded 10% for more than two-thirds of participants. For the Harris-Benedict, Mifflin, and Owen equations, every 100 kcal/day increase in measured RMR was associated with a 6% to 8% decrease in error. The optimal prediction range (within 10% of the measured RMR) was different for each: Owen equation 1105 to 1400 kcal/day, Mifflin equation 1280 to 1595 kcal/day, and Harris-Benedict equation 1345 to 1630 kcal/day.

Prediction equations should be modified according to the amount of corresponding percentage error. Where possible, RMR should be measured. Barring this, the Owen equation should be used for young, non-obese women.