Effects of Diet and Exercise on Circadian Glycemia

Specific aims of the study are: 1. to evaluate whether a 24-h exposure to a 25%-carbohydrate diet will reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h),. and 2. to determine whether one hour of post-meal moderate intensity exercise (at 50% of maximal effort) will further reduce postprandial glycemia. The outcome measures are: plasma concentrations of glucose, insulin, glucose-dependent-insulinotropic peptide (GIP), leptin, and the ketone body beta-hydroxybutyrate.