Impact of Meal Timing on Glycemic Profiles in Adolescents with Type 2 Diabetes

CANDIDATE: Alaina Vidmar is a pediatric clinical scientist specializing in treatment of adolescents with obesity and type 2 diabetes (T2D). The proposed study will focus on investigating if time-limited eating (TLE: 8-hour eating/16-hour fasting) in adolescents with T2D reduces glycemic excursions, delays β-cell dysfunction, and reduces body fat mass compared to prolonged eating period (12+hours). This K23 Award will provide her with advanced training in clinical trial design and advanced statistical methods, pediatric nutrition and body composition measurement, and glucose monitoring technology, all of which are required for her to compete for independent R01 funding. RESEARCH CONTEXT: Preliminary evidence, mostly in adults, has shown that TLE reduces body weight and fat mass, improves insulin sensitivity, reduces hepatic fat accumulation, and is safe with minimal risk when compared to prolonged eating windows and has no negative effect on daily function or lifestyle behaviors. 1–12 Because of its simplicity, TLE may represent a more feasible approach for adolescents than other caloric restriction regimens. Our preliminary data support TLE feasibility, acceptability, and safety in adolescents with obesity, with and without diabetes.13–15 However, no trial to date has studied the effects of TLE on glycemic control and body composition in adolescents with T2D. We hypothesize that TLE will reduce glycemic excursions, improve β-cell function, and reduce body fat mass in adolescents with T2D when compared to prolonged eating periods. One-hundred adolescents with T2D (aged 14-21 years), with a hemoglobin A1c (HbA1c) < 9%, and on Metformin monotherapy, will be recruited. All participants will be randomized to one of two meal-timing schedules to be followed for 12 weeks: (1) Control: >12-hour eating or (2) TLE. We will examine the effects of TLE versus control in 3 specific aims: (1) Effects on glucose control as measured by percent time in range (captured from continuous glucose monitoring data), Hemoglobin A1c, and β-cell function (mean change in insulinogenic index after a mixed meal tolerance test); (2) Effects on body composition and liver fat (DEXA and magnetic resonance imaging); and (3) Effects on sleep, physical activity, and dietary intake. CAREER DEVELOPMENT: Dr. Vidmar has access to a rich academic research environment, one of the largest pediatric T2D populations in the country, the support of her institution, and a stellar mentoring committee consisting of (1) Dr. Goran, a pediatric nutritional scientist, (2) Dr. Raymond, a physician-scientist with expertise in diabetes technology, (3) Dr. Ramon Durazo-Arvizu, a statistician, (4) Dr. Espinoza, an expert in clinical bioinformatics, and (5) Dr. Salvy, a behavioral and clinical psychologist with expertise in TLE implementation. The two co- primary mentors, Drs. Goran and Raymond will be responsible for guiding Dr. Vidmar in achieving the milestones towards transition to independence. In summary, this proposal meets a critical need for finding an effective dietary intervention for treatment of adolescents with T2D and provides Dr. Vidmar with a robust training platform, and structured mentoring path towards an R01-level competitive application.