Which REE prediction equation should we use in normal-weight, overweight and obese women?

In our modern society, there is a growing and increasing prevalence of overweight, obesity and eating disorders and young female subjects frequently ask for nutritional counselling. Resting energy expenditure (REE) is essential to provide a sound diet to subjects seeking nutritional support. We perform a critical selection of accurate and reliable prediction equations employed on normal-weight, overweight and obese young women.

REE of 157 young women of Caucasian race (18-35 years)was measured with indirect calorimetry and was compared with the principal prediction equations (Harris and Benedict, Owen, Mifflin, WHO, Bernstein and Robertson and Reid). The statistical analysis used to compare measured and the predicted REE was paired t -test, +/-95% confidence interval and Bland and Altman method. The influence of weight loss on the prediction error was estimated in 31 subjects. An additional REE measurement was performed on patients who had lost >or=5% of the initial body weight due to a sound low-calorie diet.

The equations more reliable in our study are Owen's equation in normal-weight subjects, Bernstein's equation in overweight subjects and Robertson and Reid's equation in obese subjects. Weight was a significant variable according to the stepwise regression analysis resulting in the following equation: 542.2 + 11.5 kg;R(2) : 0.59. Weight loss decisively increased the overestimation of the equations and only Owen's equation maintained the error of prediction within acceptable limits.

The equation of Owen in normal weight, Bernstein in overweight and of Robertson and Reid in obese subjects should be chosen when we have to predict REE in young women. Due to metabolic adaptation occurring during therapeutic or spontaneous energy restriction, we suggest to use Owen' s equation.