Food is any material taken from the earth to supply nutrients to an organisms for growth, reproduction or processing. Food is generally of animal, plant or fungal source, and usually contains necessary nutrients, like protein, vitamins, carbohydrates, sugars, or other nutrients essential for development. Animals include meat, poultry, fish and eggs. Plants include fruits, vegetables, grains, beans, nuts, seeds and hormones.
Plants are classified into three main categories: carbohydrates, protein and fiber. Carbohydrates provide the body with energy; protein is necessary to build and repair body tissues; and fiber gives food sustenance and allows absorption of other nutrients. Cereals, breads, potatoes and rice are good examples of carbohydrates; fruits, vegetables, whole grains and legumes are good examples of protein; and nuts, seeds and grains are rich in fiber. Each of these food groups has their own individual benefits, allowing humans to get all of the nutrients they need through diet. However, deficiencies in some of these foods may cause problems to the immune system.
The carbohydrates found in most foods provide a supply of fuel to perform various functions, such as controlling the body’s temperature, producing energy and activating the nervous system. The proteins found in most foods are essential to the body to build and repair tissues, and the vitamins and minerals found in some foods provide nourishment. A lack of any of these essential nutrients can lead to chronic diseases or disorders. Although the total amount of carbohydrates and proteins eaten in a day is important, both of them have relatively small amounts in comparison to the number of calories (mostly fats) ingested through diet.