Inclusion Criteria:  Overweight and obese men and women 21-45 years of age BMI of <40 kg/m2 normally active (>5000 steps per day) sleep: 7-9 hours per night  Exclusion Criteria:  type 1 diabetes cardiovascular disease uncontrolled hypertension smoker pregnant recent changes in hormonal birth control night shift workers take regular daytime naps operate heavy equipment Sleep less than 7 hour/night