A study, authored by researchers at the University of Bristol and Cardiff University in the United Kingdom and published in the Archives of Pediatrics and Adolescent Medicine, finds exercise does not provide the same benefits for African American girls in preventing obesity that it does for White girls. Researchers examined the physical activity of more than 1,100, 12-year-old girls, about half of whom were African Americans. The girls wore pedometers and kept detailed accounts of what they ate.
White girls who were in the most active group were 85 percent less likely to become obese over the ensuring two years than White girls in the least active group. But Black girls in the most active group were only 15 percent less likely to become obese in the next two years than Black girls in the least active group. The authors believe that Black women oxidize fat more slowly in response to exercise than White women. And Black women at rest tend to have a lower metabolic rate than White women at rest, making it more difficult for Black women to burn off calories.
The authors write, “Our results suggest that prompting adolescent girls to be active may be important to preventing obesity but that using different approaches (e.g. emphasizing reductions in energy intake) may be necessary to prevent obesity in Black girls.”