Nutrition:

The process in which food is obtained or prepared, absorbed and converted into body substances for, for growth and energy is called nutrition.

Nutrients:

Nutrients are the elements and compounds that an organism obtains and use as energy source or as components for the synthesis of new materials.

Nutrition is essential for several purposes:

1. It constitutes a source of energy for the organism.
2. It provides building material for growth and development.
3. It regulates various body functions.