Biological differences exist in the body composition of blacks and whites. We reviewed literature on the differences and similarities between the 2 races relative to fat-free body mass (water, mineral, and protein), fat patterning, and body dimensions and proportions. In general, blacks have a greater bone mineral density and body protein content than do whites, resulting in a greater fat-free body density. Additionally, there are racial differences in the distribution of subcutaneous fat and the length of the limbs relative to the trunk. The possibility that these differences are a result of ethnicity rather than of race is also examined. Because most equations that predict relative body fat were derived from predominantly white samples, biological variation between the races in these body-composition indexes has practical significance. Systematic error can result in the inaccurate estimation of the relative body fat of blacks, and therefore of definitions of obesity, if these inherent differences are ignored.
Am J Clin Nutr 2000;71:1392–402.

A current popular theory that may partially explain the high prevalence of obesity in blacks is the apparent difference in resting energy expenditure between blacks and whites. Weyer et al (9) recently found a significantly lower sleeping metabolic rate (by 301 ± 105 kJ/d; P < 0.01) in blacks than in whites after adjustment for sex, age, and body composition.