INTRODUCTION

Man needs a wide range of nutrients to perform various functions in the body and lead a healthy life. The nutrients include proteins, fat, carbohydrate, vitamins, minerals and water. These nutrients are chemical substances which are present in the food we eat daily. The foods containing these nutrients which we consume daily are classifieds as cereals, legumes (pulses), nuts and oilseeds, vegetables, fruits, milk and milk products and flesh foods (fish, meat and poultry). Protein, fat and carbohydrates are sometimes referred to as proximate principles. They are oxidized in the body to yield energy which the body needs. Vitamins and minerals do not supply energy but they play an important role in the regulation of the metabolic activity in the body and help in the utilization of the proximate principles.

ENERGY

Energy is essential for rest, activity and growth. It is well known that even when a body is at rest, it expends certain amount of energy for essential functions such as respiration, blood circulation, digestion, absorption and excretion, maintenance of body temperature etc. The amount of energy thus expended when the body is at complete rest (both mentally and physically) is termed Basal Metabolism or Resting Metabolism. Age, sex, height and weight and state of nutrition of the individual are some of the factors that influence it.

Energy requirement of an individual is based on daily energy expenditure. It is also dependent on age, body weight, level of physical activity, growth and physical status. In India, 70-80% of the total dietary calories are obtained from food grains such as cereals, millets, pulses and tubers.

Children including adolescents obtain 55-60% of their daily requirement of calories from carbohydrates.
Adolescents require more of energy for healthy growth. For example, girls and boys in 16-18 years age group require 2060 KCals and 2640 KCals respectively.

During pregnancy, additional energy is needed to support the growth of foetus and the health of pregnant women.
Energy inadequacy leads to under nutrition and at the same time, excess intake results in obesity.

ENERGY RICH FOOD

Energy rich foods includes cereals, millets, pulses, tubers, vegetable oils, ghee, butter, nuts, oilseeds, sugar, jiggery, etc., Coarse cereals like jowar, bajra and millets like ragi are inexpensive and good sources of energy.
One g of carbohydrate or protein yield 4 kcal (16.8KJ) and one g of fat yield 9 kcal (37.8KJ).

Vijayapushpam et al. 2008, Why do we need energy? NIN, Hyderabad.