New research suggests that being physically active during adolescence can help to blunt the effect of a mutation in the 'fat gene' FTO, which predisposes a person to becoming overweight or obese. Research has shown that the rs9939609 mutation of the FTO, or fat mass, gene is associated with a higher rate of body mass, fat, and waist circumference. Having one copy of the mutation is associated with an increase in weight of 3.3 lbs, and having two copies of the mutation can increase weight by 6.6 lbs. Jonathon Ruiz and colleagues at the Karolinska Institute in Stockholm (Sweden) examined data on the FTO gene collected from the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. Their results revealed that 37% of adolescents in the study did not carry any copy of the mutation, whilst 47% had one copy, and 16% had two copies. However, the FTO mutation did not appear to have any significant effect on adolescents who performed the daily recommended amount of activity. "For young people, one hour of sport per day is enough to reduce the potential risk of this genetic mutation", said Ruiz. The researchers concluded that their results show that modifying lifestyle can cancel the negative effect some genetic mutations have on health.