Food Various foods Food is any substance consumed to provide nutritional support for an organism . 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 unique metabolisms , often evolved to fill a specific ecological niche within specific geographical contexts. Food sources Most food has its origin in plants. Some food is obtained directly from plants; but even animals that are used as food sources are raised by feeding them food derived from plants. Cereal grain is a staple f...