Differences in resting energy expenditure in African-American vs Caucasian overweight females

Abstract

OBJECTIVE: The purpose of this study was to examine differences in both resting energy expenditure (REE) and respiratory quotient (RQ) between overweight African-American and Caucasian women of comparable age and body mass index (BMI). DESIGN: Cross-sectional. SUBJECTS: REE was assessed in 41 women (22 African-American and 19 Caucasian) who were recruited to participate in this study. The African-American women were aged 36.4±5.7 y with a BMI of 32.6±5.4 kg/m², and the Caucasian women were aged 35.4±5.7 y with a BMI of 31.3±3.4 kg/m². MEASUREMENTS: Body composition was assessed using dual energy x-ray absorptiometry (DEXA). REE was assessed via the dilution technique following an overnight fast. RESULTS: REE was lower in African-Americans (7279±825 kJ/d) compared to Caucasians (7807±854 kJ/d) (P=0.051). Analysis of covariance showed that REE remained significantly lower in African-American women after correcting for body weight and lean body mass. There was no effect of ethnicity on RQ. CONCLUSION: These results indicate that there is a significant difference in REE between Caucasian and African-American overweight women. This difference in REE may contribute to the higher rates of obesity found in the African-American population. This difference may also partially explain the smaller weight losses typically seen in African-American women when compared to Caucasian women enrolled in a weight loss program.