RESTING ENERGY-EXPENDITURE IN OBESE AFRICAN-AMERICAN AND CAUCASIAN WOMEN

The prevalence of obesity among African American women approaches 50% and greatly exceeds rates for Caucasian women. In addition, black wome n lose less weight than white during obesity treatment and gain more w eight when untreated. This study assessed resting energy expenditure ( REE) and body composition in obese white (n=122) and black (n=44) wome n to explore the relationship between biological variables and these o bserved differences. REE and body composition were assessed by indirec t calorimetry and densitometry, respectively, before weight loss. REE was significantly lower in black subjects (1637.6 +/- 236.9 kcal/d) th an in white (1731.4 +/- 262.0) (p=0.04). REE remained significantly lo wer in blacks than whites after adjusting for body weight (p=0.02). RE E, adjusted for fat-free mass, was also significantly lower in blacks than whites (p<0.0001), although the overestimation of fat-free mass b y densitometry in blacks may have contributed to this finding. There w ere no differences between the groups in respiratory quotient. These r esults suggest that a decreased REE may exist in obese black women, an d it may be related to the observed differences between black and whit e women in the prevalence of obesity and in the response to weight los s treatment. These cross-sectional findings await confirmation in long itudinal studies.