Food, clothing and shelter form the basic needs of man. The nutritional elements of food, which are essential for all the life processes, make food one of our basic needs. This is why 'food' comes first in the basic necessities of man. When we talk of food basics, we intend to express the body's requirement of food. Let us look at food's nutritional elements and the roles they play in maintaining metabolism. Carbohydrates, fats, vitamins, minerals, proteins, fiber and water constitute the basic nutritional elements of food. They are categorized based on the amounts in which the body requires them. The nutrients required in relatively larger amounts by the body are classified as macronutrients. Carbohydrates, fats, proteins, water and fiber belong to this class of nutrients. Vitamins and minerals are required in comparatively smaller amounts and hence called micronutrients. Carbohydrates, fats and proteins are the sources of energy. Carbohydrates give four Calories of energy per gram while one gram of fat gives nine Calories of energy. Molecules of carbohydrates and fats are composed of carbon, hydrogen and oxygen atoms. Proteins additionally contain nitrogen atoms. Foods contain some or all the nutrients in certain proportions. It is these nutritional elements that help maintain metabolism of the body and keep us healthy. Carbohydrates: Based on the number of sugar units they contain, carbohydrates are classified as monosaccharides, disaccharides, or polysaccharides. They contain 1, 2 and 3 or more sugar units respectively. Carbohydrates require less water to digest and make up the most common source of energy. As the body can obtain energy from proteins and fats, they are not the essential nutrients. Carbohydrate-rich foodstuffs include bread, pastas, rice and beans. Fats: They contain fatty acids and glycerol. If a molecule of fat has all its carbon atoms bonded to hydrogen atoms, it is known as a saturated fat. In case, some of its carbon atoms are doubly bonded to each other, it is an unsaturated fat. Saturated fats are solids while unsaturated fats are liquids. Fats disintegrate forming fatty acids and glycerol. Fatty acids are an essential dietary need while glycerol is used to produce glucose. This makes fats the energy stores of our body. Apart from this, they act as a buffer for diseases, they maintain body temperature and assist the functioning of cells. Fats act as solvents for vitamins A, D, E and K. Body can absorb these vitamins only with the help of fats. Nuts, oil and butter contain fats. Fats are also responsible for healthy skin and hair. Vitamins: Vitamins work like hormones. They regulate cell and tissue growth. They are vital nutrients. Each of the vitamins if consumed in amounts less than those required by the body, leads to a deficiency disease. This makes evident their importance to the body.

• Vitamin A, known as retinal, plays a major role in eyesight. Its deficiency leads to night-blindness. Sources of this vitamin include carrots and cod liver oil.
• Vitamin B comes in different forms such as B1, B2, B3, B5, B6, B7, B9 and B12. Rice bran is a major source of vitamin B1 while B2 is found in eggs. Liver provides other forms of this vitamin. B6 plays a role in protein metabolism and formation. It is necessary for the development of a healthy immune system. It plays a crucial role in fertility. Vitamin B12 is important for proper functioning of the nervous tissue. B1 with the chemical name thiamine is responsible for neural function and carbohydrate metabolism. It is necessary for healthy mucus membranes. B2 is instrumental in the maintenance of normal vision and healthy skin. It is a coenzyme used in metabolism of energy. Deficiencies of vitamins B6 and B12 may lead to Anemia. Deficiency of B9 in pregnant women leads to birth defects in children.
• Vitamin C is an antioxidant. It helps maintain healthy gums and teeth. It increases absorption of iron by the body and helps fight infections. Citrus fruits, cabbage, pineapples and broccoli are rich sources of vitamin C.
• Sunlight is the richest source of vitamin D. Cheese, liver and salmon are others. This vitamin helps in the absorption of calcium and phosphate and plays a vital role in the health of bones and teeth.
• Functions of vitamins are so much inter-related. Vitamin E helps prevent destruction of vitamins A and C. Wheat germ and green leafy vegetables are rich in vitamin E.
• The synthesis of proteins in plasma, bones and kidneys is brought about by vitamin K. It is also necessary for normal clotting of blood. Spinach, lettuce, cabbage and cauliflower are sources of vitamin K.

Minerals: Oyster shell is a natural source of minerals. Iodized salt is an example of a mineral added as a supplement. Calcium, magnesium and phosphorous, helpful in the growth and health of bones are a few of the essential minerals. Sodium, potassium, iodine as also iron and zinc are other useful dietary minerals. Proteins: Proteins are often known as the building blocks of the body. The amino acids that they contain form the structural elements of the body. Proteins are particularly needed during the growth period of any animal. Meat, grains, eggs and milk are rich in protein. Fiber: The indigestible portion of plant food constitutes dietary fibers. They ease the defecation process. They provide the body with the very necessary roughage, which plays a major role in the process of digestion. Whole grain food, bran and celery are fiber-rich. Water: We all know that 70% of the human body is water. This fact is sufficient to illustrate the importance of water as a basic nutrient. Human body needs around 1-7 liters of water everyday. Need of water depends on the physical activity of every individual. Water prevents the dehydration of the body. Nutrition is a science. It is a key to maintain an optimal state of health. We don't 'live to eat' but we definitely 'eat to live'. Right food consumed in right quantities helps us lead a healthy and a happy life.