2. Participants must not have evidence of diabetes mellitus requiring treatment with medications prior to screening visit. The cannot have a random or post-challenge glucose ≥ 200mg/dl (from prior labs), A1c level ≥ 6.5% (from prior labs), prior physician diagnosis, or use of anti-diabetic medications. If participants have glucose levels in the diabetic range at screening visit, they will be eligible to continue in study as long as glucose levels are not > 200 mg/dl.