A study conducted by the University of Leeds in England found that Poor sleep habits can increase your risk for obesity. "Because we found that adults who reported sleeping less than their peers were more likely to be overweight or obese, our findings highlight the importance of getting enough sleep," says lead researcher Laura Hardie. Exactly how much sleep is needed can vary, but 7 to 9 hours is best for adults, Hardie says. Researchers looked at more than 16,00 adults in the United Kingdom. Participants recorded how much they slept and what they ate.