Man needs a wide range of nutrients to perform various functions in the body and to lead a healthy life. The nutrients include proteins, fat, carbohydrates, vitamins and minerals. These nutrients are chemical substances which are present in the food we eat daily. The foods containing these nutrients which we consume daily are classified as cereals, legumes (pulses), nuts and oilseeds, vegetables, fruits, milk and milk products and flesh foods (fish, meat and poultry)
Man needs all these nutrients, i.e.. energy, proteins, vitamins, minerals in different amounts to grow, live and thrive. Since man derives all the nutrients he needs through the diets he eats, his diets must be well balanced to provide all the nutrients in proper proportions. In planning a diet for the community, foods have to be chosen in proper amounts to provide all the nutrients in required amounts and also keeping in view the dietary habits and availability of foods.