Resting Energy Expenditure in a Controlled Group of Young Arab Females: Correlations with Body Composition and Agreement with Prediction Equations

Abstract

Objectives: To assess correlates of body compositions measures and resting energy expenditure (REE) in young Arab females, and to compare measured REE values with values calculated from REE predictive equations. Methods: Sev- enty nine healthy women, aged 18 - 30 years, were recruited for the study. All volunteers fasted for 8 hours, abstained from vigorous physical activity, smoking and caffeinated beverages for twelve hours before measuring body composi- tion and REE. Resting energy expenditure was measured by indirect calorimetry and body composition was measured by a bioelectrical impedance analysis. Results: Measured-REE was significantly correlated with body fat mass, fat free mass, skeletal muscle mass, and soft lean mass (R2 ranges 0.498 - 0.592; p < 0.001). Fat-free mass had the highest cor-relation with measured REE (0.592). Resting energy expenditure predicted by Harris-Benedict equation was signifi-cantly higher (+90.2 kcal, p < 0.001), and REE predicted by Owen equation was significantly lower (−101.9 kcal, p < 0.001) compared to measured REE. Measured REE was not significantly different from REE predicted by either Mifflin equation or WHO/FAO/UNU equation (p > 0.05). Mean measured REE varied significantly with BMI (p < 0.001), but not with age or ethnic background. Conclusion: All body composition measures were significantly correlated with REE measured. Mifflin-St. Jeor equation showed the closest estimate to the measured REE in predicting REE of participants who had a normal weight or were overweight. Harris-Benedict equation significantly overestimated REE and Owen significantly underestimated REE.