Weight Loss With Meal-Replacement Therapy in Teens

This study will involve 130 adolescents (ages 13-17 years old) participating in meal replacement therapy and will last one year (12 months). Participants will be asked to strictly follow the individually-prescribed eating regimen, which will include shakes (breakfast and lunch) and pre-packaged frozen entrée meals for dinner, two servings of fruit, and three servings of vegetables per day. Daily caloric allotment will be tailored for each individual (number of shakes and frozen meals) by calculating the average daily caloric deficit necessary to achieve negative energy balance (using the metabolic rate/energy expenditure data). Shakes/meals will be provided free of charge - fruits/vegetables will be purchased by the participants. Guidance will be provided regarding the use of the meal replacement shakes at school, and participants will be encouraged to engage in family meal sessions despite eating different foods. We will measure the changes in resting metabolic rate, traditional clinical risk markers (TG, HDL-c, LDL-c, TC, glucose, insulin), vascular function, weight-related quality of life, and physical activity.