Various Functions of food
Foods are classified according to their functions in the body.
This group includes foods rich in carbohydrate, fat and protein. One gram of carbohydrate gives 4 calories.
One gram of protein gives 4 calories. One gram of fat gives 9 calories. This group may be broadly divided into two groups:
i. Cereals, pulses, nuts and oilseeds, roots and tubers.
ii. Pure carbohydrates like sugars and fats and oils.
Cereals provide in addition to energy large amounts of proteins, minerals and vitamins in the diet. Pulses also give protein and B vitamins besides giving energy to the body.
Nuts and oilseeds are rich in energy yielding as they are good sources of fats and proteins. Roots and tubers though mainly provide energy, they also contribute to some extent to minerals and vitamins.
Pure carbohydrates like sugars provide only energy (empty calories) and fats provide concentrated source of energy and fat soluble vitamins.
Body building :
Foods rich in protein are called body-building foods. They are classified into two groups:
i. Milk, egg, meat, fish:
They are rich in proteins of high biological value. These proteins have all the essential amino acids in correct proportion for the synthesis of body tissues.
ii. Pulses, oilseeds and nuts:
They are rich in protein but may not contain all the essential amino acids required by the human body.
Protection and regulation :
Foods rich in protein, vitamins and minerals have regulatory functions in the body e.g., maintaining the heart beat, water balance, temperature. Protective foods are broadly classified into two groups.
i. Foods rich in vitamins and minerals and proteins of high biological value e.g., milk, egg, fish, liver.
ii. Foods rich in certain vitamins and minerals only e.g., green leafy vegetables and fruits. Maintenance of health
Food contains certain phytochemicals and antioxidants which help in preventing degenerative diseases. Food plays an important role in the prevention of cancers, heart diseases and in controlling diabetes mellitus.
Some examples for functional foods are whole grains, soyabean, green leafy vegetables, coloured fruits and spices.