Medifast is clinically proven. Developed by a physician, it's been recommended by more than 20,000 doctors since 1980. Medifast products are formulated with a high Fullness Index so you don't feel hungry. You lose weight quickly — up to 2 to 5 lbs lbs a week — while learning how to eat healthier. Medifast Meals are formulated with low-fat protein and fiber, and fortified with vitamins and nutrients, so you lose pounds and inches without losing out on essential nutrition. The low-glycemic index formula of Medifast Meals makes them perfect for everyone, even people with type 2 diabetes.