Blood Glucose Stability and Variability on Two Diets

This study will investigate glycemic stability and variability in response to two diets: usual diet and a commercially available portion-controlled diet. The commercially available diet will be the Nutrisystem-D program, which consists of pre-packaged meals and snacks that are supplemented with grocery items, including fruits, vegetables, and dairy items. This trial will be a randomized cross-over trial of 15 patients with type 2 diabetes (weight stable for at least 3 months prior and medication stable throughout the trial). Participants will consume each diet for a 2-week period. During each diet period, participants will wear a blinded (i.e., providing no feedback) continuous glucose monitoring (CGM) device to assess glycemic stability and variability, and will be instructed to keep a detailed record of food and beverage intake and physical activity. The two diet/assessment periods will be separated by a 1-week washout period during which no dietary instruction will be given and no outcomes will be measured. Laboratory values (HbA1c, glucose, insulin, lipid panel) and physical measures (height, weight, waist circumference, blood pressure) will be assessed at the baseline for descriptive purposes. Primary Hypothesis: A significantly greater percentage of CGM readings will fall in the euglycemic range (71-180 mg/dl) during consumption of the Nutrisystem-D program, as compared with Usual Diet. Secondary Hypothesis: Participants will have significantly smaller areas under the curve, mean amplitude of glycemic excurisions, mean, standard deviation, and interquartile range of glucose values, and a smaller of percentage of values in the hypo- (\</= 70 mg/dl) and hyperglycemic (\>180 mg/dl) ranges during consumption of the Nutrisystem-D program, as compared with Usual Diet.