Living beings need food to survive. Food provides the essential raw material that the body needs to grow and stay healthy. It also provides energy to carry out various life processes.
In other words, food serves to:
provide energy to carry out life processes, such as respiration, digestion, excretion, etc.
help in growth of the body and repair of worn-out and damaged cells and tissues.
help in the production of enzymes and hormones in the body.
Nutrition is defined as a process by which living beings obtain food, change food into simple absorbable forms and use it to make substances needed by the body.