Functions and Classification of Foods

  Food nourishes the body.  Food influences long term health prospects of an individual.  Food is consumed for various reasons. 

Functions of Food

Physiological Function

Food satisfies hunger and has satiety value.  Food helps in maintaining normal secretions enzymes and hormones.

Food supplies nutrients.  Nutrients that are obtained through food have vital effects on physical growth and development, maintenance of normal body function, physical activity and health.  nutritious food is needed to sustain life and activity.  Different nutrients perform different functions.  The nutrients must be obtained through a judicious choice and combination of foodstuffs from different food groups.  Due to the presence of certain chemical substances like antioxidants food helps in preventing diseases.

Social Function

Food is a symbol of hospitality and friendship throughout the world.  offering a cup of coffee or tea is a symbol of friendship.  In times of disaster or sorrow food is offered to the affected person.

Food has been a part of community, social, cultural and religious life.  Special foods are distributed as prasad in the religious functions.  Feasts are given at specific stages of life such as birth, naming cermony, birthdays and marriages.  Even during death ceremony food is offered to relatives.  Offering food to beggars is a ritual since ancient times.  Now-a-days  annadanam    is  done regularly in temples.

Food  creates a relaxed atmosphere.  Food is served in executive meetings and lunch-ones are served in political meetings.  Visitings dignitaries of a country are offered banquet lunches.  Food is shared in pot-luck parties.

     Food is used as an expression of love, friendship and social acceptance.  Sweets are distributed to friends and relatives during festival season.  Happiness is shared with friends and relatives after being successful in an examination.

Psychological Function

      Consumption of food not only satisfies hunger physiologically but gives mental happiness.  Food eaten with close relatives and friends gives greater satisfication.

Food is an outlet of function.  As a result, people eat more when thy are tensed or happy.  Some may not eat food when they are worried.  Intake of food may be affected in sick and hospitalised patients.  Anger and frustration may turn one against food.  For some people loneliness and boredom are relieved by continuous nibbling the food.  people become overweight or underweight when psychologically disturbed.  Food is gratification of pleasure and a relief from stress. 

Some foods are forbidden like onion, garlic, and meat by brahmins due to cultural restrictions. 

 Food is a source of security.  People feel reasonably secure when they have enough food stored up.  Familiar foods gives a sense of security when one has to  eat from home.

Thus for an average man food is more than a substance supplying nutrients for health.  It is the sum of culture and traditions, emotional gratification of pleasure and relief from stress, a means of communication, security and status symbol. 

Classification of Foods

      Food are classified according to their functions in the body.

I) Energy Yielding

     This group includes foods rich in carbohydrates, fat and protein.   One gram of carbohydrate gives 4 calories.  One gram of protein gives 4 calories.  One gram of fat gives 9 calories.  The group may be broadly divided into groups:

*Cereals, pulses, nuts and oilseeds, roots and tubers.

*Pure carbohydrates like sugars, fats and oils.

Cereals provide in addition to energy, large amounts of protein, 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 mineral sand vitamins.

Pure carbohydrates like sugars provide only energy (empty calories) and fats provide concentrated source of energy and fat soluble vitamins.

II)Body building

      Foods rich in protein are called body-building foods.  They are classified ino two groups:

*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.

*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 etc.  Protective foods are broadly classified into two groups.

*Foods rich in vitamins and minerals and proteins of high biological value; e,g., milk, egg, fish, liver, etc.

*Foods rich in certain vitamins and minerals only; e.g., green leafy vegetables and fruits.

Maintence of health

      Food contains certain phytochemicals which act as antioxidants.  These help in preventing degenerative diseases.  Phytochemicals are non-nutrient compounds found in plant derived food that have biological activity in the body.  Antioxidants include compounds that protect biological systems against the potentially harmful effects of processes or reactions that can cause excessive oxidation.  Food plays an important role in the prevention of cancers, heart diseases and in controlling diabetes mellitus, due to the presence of antioxidants.