The food chain describes the arrangement of living things in a particular environment. In nature, food is any material consumed to supply nutrition to the organisms for their daily life. Food is generally of animal, plant or fungi origin, and has necessary nutrients, including proteins, carbohydrates, vitamins, or other minerals. In most modern diets, food is either totally avoided or consumed in inadequate quantities.
In a healthy diet, the major food groups (protein, carbohydrate, vegetable and fruit) are provided in adequate amounts. The main food groups are: protein foods – meat, fish, poultry; carbohydrates – bread, pasta, rice; and fat foods – butter, margarine, cooking oil. In addition to these, some food types are available at different prices, such as cereals, beans and legumes; dairy products; fruits; vegetables; whole grains; oils; and alcoholic beverages. In a healthy diet, each nutrient can be consumed in adequate quantities, with the main exception of fat and carbohydrates. The main purpose of food is to increase the ability of the organisms to live by providing energy, so that growth can be properly stimulated.
Food availability is usually patchy in different areas of the world, although the distribution of food remains fairly constant. Food is usually eaten on a regular basis, either as a staple food or as a snack. In the United States, a large amount of the population eats fast food on a regular basis. The food pyramid shows how much of the various food groups should be eaten each day to maintain normal health. Foods eaten outside the balanced diet are not factored into the pyramid, but are represented by a lower number than the food groups represented by the food pyramid.