(CBS News) High amounts of exercise may not help black girls may not stave off obesity as well as their white counterparts.
Recent research, published in the June 2012 issue of Archives of Pediatrics & Adolescent Medicine, revealed that black girls who were active at 12 years old were almost just as likely to be obese at the time they reached 14 as African American girls who didn't exercise that much.
In 2010, black women were 70 percent more likely to be obese than white women, according to the U.S. Department of Health and Human Services, Office of Minority Health. The number increases for teens: Black girls were 80 percent more likely to be obese than white girls from 2007 to 2010. As a whole, four out of five black women are overweight or obese, and African Americans were 70 percent less likely to exercise than white people in 2010.
"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," Dr. James White of Cardiff University in Cardiff, Wales and Dr. Russell Jago of the University of Bristol in Bristol, England wrote in the study.
For the study, researchers followed 1148 adolescent girls (538 black and 610 white) between the ages of 12 and 14. Their level of physical activity was recorded using an accelerometer and their food intake was recorded in three-day periods. The amount of time spent sitting and watching TV was also taken into account. The subjects' body fat was measured by using Body Mass Index (BMI), and percentage body fat was measured using calipers.
The black girls in the group with the most physical activity were only 15 percent less likely to be obese by age 14 than the group with the lowest levels of exercise. When it game to white girls, the active group was 85 percent less likely to have weight problems.
"It creates yet another barrier to what might already feel like a struggle," Ginny Ehrlich, chief executive of the Alliance for a Healthier Generation, said to the Los Angeles Times. "When we talk with young people, we talk about healthy living -- eating better and moving more. We're trying to stay away from messaging around obesity."
Toni Carey, who founded the national running group Black Girls Run!, told the Los Angeles Times that getting African American girls to exercise was already an uphill battle. When she began running her mother told her, "That's something that black people don't do" - and mentioned that her uterus was going to fall out and other myths. Carey also said that diets are often unhealthy because single-parent homes often turn to cheap fast food to feed their families and family cooking normally includes less healthy dishes.
She explained, "If you aren't seeing your peers out there running and exercising, or you hear them say, 'I don't want to mess up my hair,' it's more than likely you're not going to engage in that physical activity."
Alison Field, who studies weight in adolescents and women at Harvard Medical School and Children's Hospital in Boston and was not involved in the study, suggested to Reuters that the study results may show that the typical recommendation of more exercise may not be ideal for African American girls. It might mean that diet and other lifestyle changes need to be made to help maintain weight.
"I think everyone would agree we need people to be active," Field said. "It's not sufficient on its own to prevent weight gain, but it's really an important part of the equation."