Foods and beverages are any substances that can be consumed for nutritional value and to provide energy. Food is the main source of energy and of nutrition for animals, and is usually of animal or plant origin. Nutrients in food are grouped into several categories. Macronutrients means fat, protein, and carbohydrates. Micronutrients are the minerals and vitamins. Additionally food contains water and dietary fiber. In The Blood Type Diet System foods are often categorized and beneficial, neutral or avoid based on the reactivity of their constituent ingredients (such as Lectins?) with the biochemistry of a particular blood group.