If you’re an African-American woman struggling to lose weight, a new study shows that your troubles might not lie solely in your eating and exercise habits, but rather in your DNA. A report published in the International Journal of Obesity finds that African-American women lose less weight than their Caucasian counterparts, even with comparable dietary and physical activity routines.
According to the study, the reason for the difference is that black women’s metabolisms — the process by which your body converts food into energy — are slower than white women’s. Thus, they burn fewer calories per day, which causes them to lose less weight. This means that African-American women have to either burn more calories (i.e., exercise more) or ingest fewer calories (i.e., eat less) in order to lose the same amount of weigh as Caucasian women. Even when resting, white women burn more calories due to their higher metabolism.
The study, conducted by the University of Pittsburgh School of Medicine, involved 105 “severely obese” women — 39 black and 66 white — with similar body mass index (BMI) measurements (a measurement of body fat based on height and weight). They were placed on the same low-calorie diet (1,800 calories per day) and given the same exercise regimen. After six months, the black subjects lost an average of seven to eight pounds less than the white subjects. Using electronic monitors and other means, a close eye was kept on the women so that there would be no impact on the findings due to individuals cheating on their diets or slacking on their exercise.
Differences in metabolism have typically been attributed to age (the rate slowing after age 40), gender (men’s rates being faster than women’s), body type (more muscle or more overall weight triggering a higher rate) and family heredity, but now race may also have to be taken into consideration. As such, doctors and other medical professionals specializing in weight loss should factor in race when coming up with diet and exercise regimens for their patients.
One possible reason for the racial difference in metabolic rates is that the American diet is based largely on European foods, meaning that people of European descent may have bodies that have evolved to burn these foods more efficiently. Backing up this theory are studies that show that Asians with Western diets have issues with metabolism and diabetes at a much lower BMI than white people.
Due to a lack of data, it remains to be seen if there is a similar difference in metabolism between African-American males and Caucasian males, but early indications imply that there is little or no such disparity.
(Sources: University of Pittsburgh School of Medicine, HealthDay, WebMD, National Institutes of Health)