Inclusion Criteria:

• * Age 10-70 years
• * Prior participant of the UPenn Biobank or Center for Applied Genomics Biobank and agreed to be recontacted for future research.
• * Adults with BMI 25kg/m2 or higher, children and adolescents with BMI 85th percentile or higher

Exclusion Criteria:

• * prior diagnosis of type 1, type 2, or secondary diabetes
• * use of medications that would impact glucose and insulin response such as steroids, metformin or other anti-diabetic medication
• * acute illness that may impact insulin and glucose dynamics
• * pregnancy
• * hypothalamic obesity or related genetic disorder of metabolism
• * recent systemic chemotherapy use
• * gastrointestinal impairment or surgery that may impact absorption
• * anemia
• * major organ system illness or any underlying condition requiring regular medication or treatment that could make implementation of the protocol or interpretation of the study results difficult
• * inability to comply with study protocol