Food is any material consumed to provide nutrition to an organism. It may be in the form of food or a nutrient in the form of plants or animals. Food is generally of animal, plant or fungal source, and has various important nutrients, including protein, fats, carbohydrates, vitamins, or other minerals. In fact, all living things are made up of complex blends of food materials, which constitute the basic content of biomass or matter that can be further broken down to supply the energy needed by the living organisms to function normally.
Plants manufacture carbohydrates by means of photosynthesis, while animals eat meat to derive protein and energy. Fungi consume cellulose and produce gums, while animals contain proteins as major food components. The animal products that derive complete proteins include milk, meat, eggs, fish, and poultry. Plants, on the other hand, derive complete proteins from either animal or plant material. Animal foods that are rich in protein include red meat, poultry, fish, milk, cheese, beans, vegetables, fruits, nuts, and seeds, while plant foods that are rich in carbohydrates include corn, wheat, cereals, potatoes, rice, fruits, vegetables, sugar, and honey.
Under the subject of nutrition, there is much debate concerning which food types, what proportions of each food type should be consumed, and how much of a certain food type should be eaten, etc. Various experts and authorities have formulated various concepts on the basis of food types, proportions of each food type, and the nutrition value of food. It has been seen that children, who follow a vegetarian or vegan diet, obtain the required amount of nutrients by eating fresh green vegetables, legumes, grains, beans, etc. But, even after following a strict vegetarian or vegan diet, the researchers found that children showed normal growth and did not become overweight or suffer from chronic diseases.