Researchers have discovered that sleeping too much or too little can increase the likelihood of becoming obese. The study found abnormal sleeping patterns increased the risk of being overweight. The effect was seen regardless of diet, health or socio-demographic group. Researchers found that in people with a high genetic risk of obesity, both short-sleep and long-sleep durations further increased risk of carrying excess weight, compared with people who slept for normal durations of between seven and nine hours a night.