Food is one of the basic necessities of life. Food contains
nutrients—substances essential for the growth, repair, and maintenance of
body tissues and for the regulation of vital processes. Nutrients provide
the energy our bodies need to function. The energy in food is measured in
units called calories. Food is any substance consumed by an organism for
nutritional support. Food is usually of plant, animal, or fungal origin and
contains essential nutrients such as carbohydrates, fats, proteins,
vitamins, or minerals. The substance is ingested by an organism and
assimilated by the organism's cells to provide energy, maintain life, or
stimulate growth. Different species of animals have different feeding
behaviours that satisfy the needs of their metabolisms and have evolved to
fill a specific ecological niche within specific geographical contexts.
