When it comes to being overweight, it seems you can no longer blame your genes. A new study published by a Miller School genetics researcher in the Archives of Internal Medicine shows that an extra three to four hours of moderate activity a day can help you overcome a genetic predisposition to obesity.

Previous genetic studies have identified the Fat Mass and Obesity Associated (FTO) gene, which contributes to weight gain and higher body mass index.

The National Institutes of Health-funded study focused on 704 Old Order Amish adults in Lancaster, Pennsylvania, who were already enrolled in the Heredity and Phenotype Intervention Heart Study, which is examining how genes and lifestyle factors may affect their risk of developing cardiovascular disease.

“The Amish were an ideal group to study since they live a fairly homogeneous lifestyle, eat similar foods, abstain from alcohol, and participate in similar types of activities,” explains Evadnie Rampersaud, M.S.P.H., Ph.D., lead author of the study, assistant research professor in the Dr. John T. Macdonald Foundation Department of Human Genetics, and a member of the Miami Institute for Human Genomics at the Miller School.

The link between a variant in the FTO gene and a higher body mass index among the Amish was consistent with earlier findings; however, the researchers wanted to know if physical activity could offset the gene’s influence on body weight. They had the participants wear a battery-operated monitoring device round-the-clock for a week.

“What we found is that among those Amish with the gene variant, those who got about six or nine hours of physical activity a day weighed up to about 15 pounds less than the least active people,” explains Rampersaud. “These findings clearly show that even genetically susceptible people who have the so called ‘obesity gene’ can alter their risk by becoming more active.”

Rampersaud conducted the study while at the University of Maryland with co-author Soren Snitker, M.D., Ph.D., assistant professor of medicine and pediatrics.