Regular physical activity can reduce the risk of obesity in people who have a genetic predisposition to being overweight, according to a study in Monday's issue of the Archives of Internal Medicine.

Variations of a particular gene, known as the fat mass and obesity associated (FTO) gene, are widely acknowledged to be linked with a high body mass index, but only for those on the lower end of a scale of physical activity.

On average, it takes an extra 900 kilocalories expended every day to overcome the effects of the gene, according to the study.

In this study, researchers analyzed DNA samples from 704 healthy Amish adults of average age 43.6, and conducted a series of physiological tests on the participants, including recording their physical activity over a seven-day period.

Among the participants, fifty-four percent of the men were overweight and 10 percent obese. About 64 percent of the women were overweight and 31 percent obese.

The group was divided into people with high activity levels and low activity levels. The highly active group burned about 900 more calories per day than the lower activity group. That equals about three to four hours of moderately intensive physical activity, such as brisk walking, house cleaning, or gardening, according to the researchers.

The study showed that people with certain variations of the FTO gene were more likely to be overweight.

However, the researchers found that being genetically predisposed to obesity "had no effect on those with above average physical activity scores."

(Xinhua News Agency via Agencies September 9, 2008)