Looking to slim down? Don't skimp on sleep.A new study, published in the journal "Plos One," found that people who average six hours of sleep a night have a waist circumference about 1.2 inches larger than those who get nine hours a night.Researchers also measured blood pressure and weight of the people who slept the least and found they had the bleakest outcomes.There are, however, other factors that need to be taken into account.The study relied on "self-reported" data, and didn't measure results over a long period of time.