Nutrients are defined as constituents of food, which perform important functions in our body. If these nutrients are not present in our food insufficient amount, the result is ill health. The important nutrients include carbohydrates, proteins, lipids, vitamin, minerals and water. Food also contains many non-nutrient substances e.g. colouring and flavouring substances in food.
Our body needs all the nutrients in right quantities for growth, maintenance and for preventing nutritional deficiencies. When all essential nutrients are present in correct amount and proportion as required by our body it is called optimum nutrition or adequate nutrition. Optimum Nutrition is required to maintain good health.