Getting more sleep may help curtail a genetic predisposition towards being overweight, according to a new University of Washington study. Because both body mass index (BMI) and the need for sleep are influenced by genetics, researchers analyzed the height, weight, and sleep patterns of more than 1,000 sets of both identical and fraternal twins. They found that those who slept longer had lower BMI’s, with genetic factors influencing 32 percent of weight variations for long sleepers (nine or more hours a night), 60 percent for normal sleepers (seven to 8.9 hours a night), and 70 percent for short sleepers (less than seven hours a night). "The less sleep you get, the more your genes contribute to how much you weigh," says lead author Nathaniel Watson. "The more sleep you get, the less your genes determine how much you weigh." The research reinforces the connection between sleep deprivation and weight gain, but the researchers do not yet understand how sleep sleep influences a genetic predisposition toward gaining weight.