TOTAL DAILY ENERGY-EXPENDITURE IN FREE-LIVING OLDER AFRICAN-AMERICANSAND CAUCASIANS

Low rates of daily energy expenditure, increased energy intake, or a c ombination of both contribute to obesity in African-Americans. We exam ined whether African-Americans have lower rates of free-living daily e nergy expenditure than Caucasians. One hundred sixty-four (>55 yr) vol unteers (37 African-American women, 52 Caucasian women, 28 African-Ame rican men, and 47 Caucasian men) were characterized for total daily en ergy expenditure, resting metabolic rate, and physical activity energy expenditure from the doubly labeled water method and indirect calorim etry. Absolute total daily energy expenditure was lower in women than men but was not different between African-Americans and Caucasians. Ho wever, we found race and gender differences in total daily energy expe nditure after controlling for differences in fat-free mass. Total dail y energy expenditure was 10% lower (P < 0.01) in African-Americans com pared with Caucasians due to a 5% lower resting metabolic rate (P < 0. 01) and 19% lower physical activity energy expenditure (P = 0.08). Mor eover, total daily energy expenditure was 16% lower (P < 0.01) in wome n compared with men due to a 6% lower resting metabolic rate (P = 0.09 ) and a 37% lower physical activity energy expenditure (P = 0.06). Low rates of energy expenditure may be a predisposing factor for obesity, particularly in African-American women.