Sleeping more may help you fight a genetic predisposition to gain weight, according to a study in the May issue of SLEEP.

Researchers at the University of Washington examined sleep and body mass index (BMI) in 1,088 pairs of twins. They found that sleeping more than nine hours a night may actually suppress genetic influences on body weight. Sleeping less than seven hours a night was associated with both increased BMI and greater genetic influences on BMI.

“The less sleep you get, the more your genes contribute to how much you weigh. The more sleep you get, the less your genes determine how much you weigh,” said lead author Nathaniel Watson, MD.

Previous research has shown the connection between sleep and weight, but this study looks at the role of genetics.