Metabolism of Low Carbohydrate and Ketogenic Diet

Participants in both groups will receive standardized health education sessions including lifestyle management, blood glucose control, blood pressure control, and prevention of diabetic complications from trained providers who are also investigators of this study. The lifestyle intervention from the evidence-based Group Lifestyle Balance (GLB) program (http://www.diabetesprevention.pitt.edu/index.php/for-the-public/for-health-providers/group-lifestyle-balance-curriculum/) and Look AHEAD intervention (https://www.lookaheadtrial.org) will be modified for this study. Goal for weight loss and physical activity will be set for each participant based on recommendations from GLB and Look AHEAD. Lifestyle intervention will be delivered through interactive digital lessons. Smart phone and mobile health devices will be used for each participant to self-monitor diet, physical activity, weight, glucose level, blood pressure, and blood ketone (if randomized to the low-car/ketogenic diet group). Control group (mHealth+ low-fat diet group): The low-fat group will be asked to restrict total calorie and total fat consumption according to the Look AHEAD intervention and MyPlate guidelines, with 26-44% carbs, 10-30% protein, and less than 30% fat. Intervention group (mHealth+ low-carb/ketogenic diet group): The low-carb/ketogenic diet group, will have total calorie set according to Look AHEAD intervention, and carb consumption restriction will be set based on recommendations from American Diabetic Association, National Kidney Foundation, and other evidence-based resources. Participants in this group will be asked to consume a low-carb/ketogenic diet. Specially, participants will receive a carbohydrate, protein, and fat intake goal based on 1.5 : 1 ratio (1.5 grams of fat to 1 gram of carbohydrate and protein combined). Daily macronutrient and calorie consumption will be individualized for each participant using ideal body weight as inferred from wrist circumference and activity level. Carbohydrate consumption will be less than 10% (20\~50 g), protein 10-20% (1.0\~1.2g/kg ideal body weight), and fat 70-80% of total daily energy, respectively. Nutritional ketosis will be reached by consuming such diet (0.5 mmol/L). All diet intervention materials will be developed by a registered dietitian according to the evidence-based guidelines. The dietitian will also be responsible to any study activities relevant to diet. These activities include but are not limited to responding to some specific diet questions to study participants and health related measurements relevant to diet changes. An interventionist, under supervision of a registered dietitian, will interact with each participant from both groups at the beginning of the intervention as an introduction visit, and three individual intervention sessions at month 1, 3, and 5. During the introduction visit, the interventionist will set up a personalized weight loss goal and caloric intake goal with the participants. The individual intervention sessions at month 1, 3 and 5 will be arranged to solve the encountered problems regarding diet, weight loss, caloric intake and action planning. Additional communication through phone call will be used to support patient dietary changes throughout the study based on their self-monitoring information.