Walking can offset the tendency to become obese

So you have fat genes, huh? OK, but your genes aren’t your destiny. A new study shows that people who are genetically prone to obesity can offset that influence by half by walking briskly one hour a day.

The study, presented Wednesday at an American Heart Assn.conference in San Diego, looked at more than 7,700 women enrolled in the Nurses’ Health Study and more than 4,500 men in the Health Professionals Follow-up study. Researchers looked at the participants’ activity levels, body mass index and their genetic predisposition to become obese (using a measure based on 32 genetic variants linked to obesity).

Each obesity-increasing gene was linked to an increase in BMI. But that effect was reduced in people who had the highest level of physical activity. People who were more sedentary, on the other hand, had more pronounced effects from each obesity-increasing gene.

“A sedentary lifestyle marked by watching television four hours a day increased the genetic influence by 50%,� said the lead author of the study, Qibin Qi, a research fellow at the Harvard School of Public Health.

It’s not clear how certain genes raise the risk of obesity or how physical activity offsets some of that risk, Qi said. But that shouldn’t stop people who come from long lines of heavy people to consider vigorous exercise as a way to escape their heredity.

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