Do African Americans have lower energy expenditure than Caucasians?

OBJECTIVE: To review current studies that examine differences in energy expenditure between African Americans and Caucasians as possible modulators of attained differences in overweight status. DESIGN: Literature review of recent clinical and laboratory studies. METHODS: Studies chosen for review were those that examined directly resting metabolic rate (RMR), using indirect calorimetry, and total daily energy expenditure (TDEE) and physical activity energy expenditure (PAEE), using doubly labeled water. RESULTS: Ten of 15 studies reviewed reported a lower RMR in African Americans than in Caucasians, The differences in RMR between African Americans and Caucasians ranged from 81 to 274 kcal/day and could not be explained by differences in age, fat-free mass (FFM) or methodological concerns. Two of six studies of energy expenditure using doubly labeled water suggest that Black adults have a tendency for lower TDEE that can be accounted for primarily by a lower PAEE. CONCLUSIONS: If future studies indicate conclusively that African Americans do have lower RMR, TDEE and PAEE than Caucasians, then the disproportionally higher risk of obesity and associated metabolic disorders in Black adults may be preventable-especially in Black women. If these race differences are indeed a result of both physiological and behavioral factors, then interventions designed to reduce caloric intake and/or increase energy expenditure through lifestyle activity or structured exercise programs become especially important for African Americans and should be encouraged.