Food is any material eaten to provide nutrition to organisms, usually for a living organism. In food the primary ingredients are protein, carbohydrate, fat, vitamins and minerals. Protein and carbohydrates are the building blocks of the body. Animal products, such as meat and milk, are considered the only animal food that provides complete nutrition. Plants are rich in protein and carbohydrates and provide only trace amounts of vitamins and minerals, which are essential to life. Food processing techniques have made it possible to transform food into processed foods that can be consumed on a daily basis without the worry of nutritional value or harmful toxins.

There are two types of dietary food: solid food and partially solid food. Solid foods include all edible parts of plants, although animal products may not be consumed with the skin. Plants are eaten in their whole forms, as well as in juices, purees, puddings, purees made from fruit, seeds and nuts. Animal foods may also be eaten, with the skin removed. Fruits and vegetables are the most commonly eaten vegetable. Milk and eggs are available in substitutes.

Diets high in carbohydrates provide energy to the body through the digestive process and are therefore included in the diet. The main source of carbohydrates is protein, which is the major component of both animal and plant foods. A number of dietary fibers are present in some foods, which help regulate the absorption of carbohydrates. However, some food types, such as some vegetables, contain little or no fiber at all, making them a poor choice for those who are trying to lose weight and are avoiding certain foods because of this. Some dietary fiber helps to slow the absorption of carbohydrates into the body and has been found useful in helping to treat certain diseases. Milk and some meats contain large amounts of carbohydrates but are low in fiber.