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 t o 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 (R 2 ranges 0.498 - 0.592; p < 0.001). Fat-free mass had the highest correlation with measured REE (0.592). Resting energy expenditure predicted by Harris-Benedict equation was significantly 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 signif i cantly underestimated REE.