Exercise is still one of the best ways to lose weight, even if obesity is in your genes.

Obesity is considered as one of the risk factors for many diseases such as diabetes, heart diseases, and cancer.

In a new study published in Public Library of American Science Medicine journal, it is shown that physical exercise can decrease genetic susceptibility to obesity by 40 percent.

The study examined 20,430 individuals from Norwich, Britain. Some of them inherited between 10 and 13 genetic variants known to increase the risk of obesity. Some inherited as many as 17 variants, while others as few as six.

Using modeling techniques, the researchers found that each genetic variant was linked to an increase in body mass index (BMI) – a measure of body size based on both height and weight.

"Each additional genetic variant in the score was associated with an increase in BMI equivalent to 445 grams (1.6 ounces) in body weight for a person 1.70 meters (5.7 feet)," the study said.

For physically active individuals, the increase was just 379 grams (13 ounces).

That was "36 percent lower than in physically inactive individuals in whom the increase was 592 grams (21 ounces) per variant," the research found.

Each additional variant also raised the individual's chances of obesity 1.1-fold, but in physically active individuals, "the increased odds per variant for obesity risk were 40 percent lower."

Ruth Loos of Britain's Medical Research Council Epidemiology Unit, who carried out the research, said the study "challenged deterministic view of the genetic predisposition to obesity."

"Our findings further emphasize the importance of physical activity in the prevention of obesity," Loos said. (With reports from AFP)