Optifast Protein Plus Shake, Vanilla Flavor - This product is part of a nutritionally complete, very low-calorie diet program. Each shake contains 28 essential vitamins and minerals for safe and effective weight loss. High in protein and a source of fiber, these shakes offer convenient, nutritious drinks that can replace one, two, or three meals. The Optifast Program is scientifically designed to help you achieve weight loss results. These shakes have a creamy vanilla flavor and are high in protein and offer complete nutrition.