Obesity researchers have found that African-American women need to consume fewer calories or do more activity to achieve the same weight-loss rates as Caucasian women who start at a similar size. They cite a lower metabolic rate to explain the greater difficulty in reducing obesity.

The University of Pittsburgh, PA, team of metabolism experts say that previous research has also found that African-American women fail to lose as much weight as Caucasians in response to medical help, and that this has raised questions about how well the group adheres to the measures put in place.

The current study, however, confirms that willingness to participate is not a factor for these women in the success of weight-loss measures to restrict calories or increase physical activity.

Findings have also ruled out that differences cannot be explained by a lack of “culturally sensitive” interventions.

James DeLany, PhD, associate professor of endocrinology and metabolism at the Pitt School of Medicine, says:

“At first, it was thought that perhaps the African-American women didn’t adhere as closely to their calorie prescriptions or that the interventions were not culturally sensitive. But even in research projects that were designed to address those possibilities, the difference in weight loss remained.”

Dr. DeLany explains that similarly sized bodies do not always respond to the same obesity measures for equal weight-loss gains – metabolism varies in different groups of people.

“We prescribe how many calories are allowed and how much activity is needed during weight loss interventions based on the premise that people of the same weight have similar metabolic rates,” he says.

Dr. DeLany adds:

But to account for their lower metabolic rate, African-American women must further reduce the number of calories they eat or use up more of them with exercise in order to lose the same number of pounds in the same time span as a Caucasian woman of the same weight.”

The study included 66 Caucasian and 39 African-American women who were severely obese. The research:

  • Examined changes in body weight and energy expenditure, and
  • Measured physical activity and energy intake.

During the 6 months of the study, the weight-loss intervention included “prescriptions” of calorie restriction and increased physical activity.

The Caucasian women achieved 3.6 kg more weight loss than the African-American women.

The research paper concludes that “neglecting to account for the lower energy requirements in African-American women” results in a “lower level of calorie restriction, and hence, less body weight loss.”

The African-Americans’ lower energy requirements were around 2,900 kcal/day, compared with around 3,100 kcal/day for the Caucasian women.

The researchers used what they call “multi-sensor activity monitors” to track physical activity during the study, and the research paper cites an example called the SenseWear armband.

This device is similar to the consumer gadgets that have gained traction in 2013 – as seen in MNT’s 2013 news review.

The armband used by the present researchers is designed specifically for clinicians to help people with morbid obesity. The manufacturer lists that it outputs:

  • Raw data from sensors that can be exported to spreadsheets
  • A graph showing different types of activity over time.

The physical activity component to weight loss has other well-established benefits. News on Friday, December 20th, revealed that walking an extra 2,000 steps every day reduces cardiovascular risk – by as much as 8%, the study in The Lancet suggests.