Teens need to exercise an hour a day to override 'fatso' gene, study says

CHICAGO -- One hour of moderate to vigorous exercise a day can help teens beat the effects of a common obesity-related gene with the nickname "fatso," according to a new European study.

The message for adolescents is to get moving, said lead author Jonatan Ruiz of the Karolinska Institute in Sweden.

"Activities such as playing sports are just fine and enough," Ruiz said.

The study, released Monday, appears in the April edition of the Archives of Pediatrics and Adolescent Medicine.

The research supports U.S. guidelines calling for an hour or more of physical activity daily, most of it aerobic.

Scientists are finding evidence that lifestyle and genes cause obesity. One such gene, the FTO gene, packs on the pounds when it shows up in a variant form. Adults who carry two copies of the gene variant -- about 1 in 6 people -- weigh on average 7 pounds more than people who don't.

In the new study, 752 teenagers who had their blood tested for the gene variant wore monitoring devices for a week.

Exercising an hour or more daily made a big difference for the teens who were predisposed to obesity.

The study was funded by the Spanish and Swedish governments and the European Union.