Inclusion Criteria:  Groups 1 and 2 (overweight and obese groups): Age 8-17 years for the visits #1 and #2, individuals can be as old as 22 years for follow-up visits #3 and 4 Overweight or obese, as defined by a BMI ≥ 85th% & <95th% or BMI ≥ 95th%, respectively by age and sex, and for those 16 years and older, BMI ≥25 and <30 and BMI ≥30 For Group 2 only: previously completed visits 1-2 in 2007-2013 and formally agreed to be re-contacted for study purposes Group 3 (Normal weight controls): Age 8-17 years Healthy weight, as defined by a BMI ≥ 5th percentile & < 85th percentile, respectively by age and sex  Exclusion Criteria:  Previous diagnosis of type 1 diabetes Use of concurrent medications known to affect glucose metabolism (metformin, oral steroids, sulfonylureas, insulin) Verbal report of Pregnancy