Food is the basic necessity of life. Regular supply of food is essential for human beings in order to keep fit and to carry on all the life processes. Food is any substance which performs the following functions in the body:

  1. yields energy for life processes
  2. builds up new cells during growth
  3. repairs worn out (damaged) tissues
  4. aids in production of useful body compounds

Biological Classification of Food

Food can be classified into three categories based on their functions:

  1. Energy providing foods
  2. Body building foods
  3. Protective or regulatory foods

1. Energy providing foods

These are rich in carbohydrates and fats and provide energy on biological oxidation in the body. Examples: cereals, sugar, fats, oils, jaggery, coconut, and groundnuts.

2. Body building foods

These are rich in proteins and help in the formation of new tissues. Examples: legumes, milk, egg, meat, fish, pulses, nuts and oil seeds.

3. Protective or regulatory foods

These are rich in minerals, vitamins, roughage and water. They help in regulation of internal metabolism in the body. Examples: green leafy vegetables, fruits, amla, guava, citrus, oranges and water melon.