A new study shows that physical exercise can reduce a genetic predisposition to obesity by an average of 40 percent. The study, recently published in the Public Library of American Science Medicine journal, is based on examination of more than 20,000 British people. The research challenges the notion that an inherited propensity to obesity is impossible to overcome and boosts the case for the benefit of more exercise for anyone looking to shed some weight. It found most of the study’s participants inherited between 10 and 13 genetic variants known to increase the risk of obesity, with others inheriting as few as six and as many as 17. The researchers also discovered that each genetic variant was linked to an increase in body mass index. For physically active individuals, the BMI increase was lower than in people who did not exercise. Researchers say the study “challenged deterministic view of the genetic predisposition to obesity” and further emphasizes the importance of physical activity in the prevention of obesity.