Food, is imperative for all living beings. Through the centuries, food has been a part of our social, cultural and religious life. It has also been used as a medium for expressing love, friendship and social status. Food is a basic necessity of life. Intake of the right kind and amount of food can ensure good health, which may be evident in our appearance, efficiency and emotional well being. Nutrients are components of foods that are needed by the body in adequate amounts in order to grow, reproduce and lead a normal healthy life. These nutrients are water, carbohydrate, fat, protein, minerals and vitamins. Our body itself is made of these nutrients in different proportions.
In good nutritious diet all these essential nutrients are present in the correct proportion as required by our body. The signs of good health are optimum height and weight for age, clear complexions, fresh, lively skin and hair, healthy pink nails, correct posture and gait, inquisitive and alert eyes, good appetite and bowel evacuation, emotional maturity, pleasing personality and an optimistic outlook to life. When nutrients are inadequate we are undernourished. An undernourished person manifests symptoms of deficiencies and feels unwell and keeps ill health.
Nutrients accomplish three functions
1 Supply energy to body
2 Build and repair the body tissue
3 Regulate the body process
Each nutrient class has its own functions. Their activities are interrelated and have to be in unison for effective action within the body. Cereal grains like wheat, rice, maize, roots and tubers like potato, sweet potato and tapioca are good source of carbohydrate. The chief function of carbohydrate is to provide energy needed by our body. Those not used immediately for this purpose are converted to fat and stored as body fat to be mobilised for energy supply when needed. A single gram of carbohydrate provides 4 kilo calories of energy. Milk eggs, meat, fish, pulses, gram and nuts are good sources of protein. Proteins function in building new tissue and maintaining and repairing those already built. Proteins provide energy when dietary intake of carbohydrate and fat are low. A single gram of protein provides energy equal to that produced by carbohydrate.
Fats like oil, butter, margarine are concentrated sources of energy. An excessive intake fat can result in deposition of fat on the body. Minerals like calcium, phosphorus, iron, iodine and others are found in all general food we consume. They are necessary for body buildings, buildings of bones, teeth and structural and soft tissues. Vitamins are essential for regulations of the body process. Vitamins are needed in very small amounts but are the most important for regulation of normal body processes. An average person must also drink 6-8 glass of water per day. Apart from the nutrients, fiber though not a digestible part of the diet are indispensable.
Every individual needs the same nutrients for similar body functions. The variable is the amount needed according to age, size, activity and physiological condition of body. An individual who carries heavy loads may need more energy than one who works at a desk. Excess energy has to be burnt by exercise, other wise they are deposited as fat in the body. Hence taking right amount of right food at the right time signifies good nutrition and is the key to sound health.