Carbohydrates: Carbohydrates are important source of energy required by your body. They provide about 72% of the calorie requirements of the body and thus act as one of the principal fuels of the body. There are two types of carbohydrates- the sugar and the starches. A starch is a long chain of sugars. Sugars can be digested and used for fuel faster than starches. If you eat more carbohydrates than you need, the excess is stored as starch in your muscles and liver. If these storage places become filled, the carbohydrates are body. As a result, a diet with excessive carbohydrates can make a person overweight.

Sources of carbohydrates: In addition to fruits, such as orange, vegetables and grain products are main sources of carbohydrates.

Fats and Oils: Like carbohydrates, fats and oils supply the body with energy. In fact, fats supply the body with twice as much energy amounts of proteins and carbohydrates. In addition to providing energy, fats help to support and cushion vital organs, protecting them from injury. Fats also insulate the body against loss of heat.

Source of Fats: Foods that are rich in fats come from both animals and plants. Some common sources of fats are nuts, butter, vegetables oils, cheese, milk, animal fat, etc.

Proteins: Every living part of your body contains proteins. Proteins are used to build and repair body parts. For example, your blood, brain and muscles are made partly of proteins. There is protein even in the enamel of your teeth. As a result, every human being needs a regular supply of the raw materials used to make proteins. Raw materials used to make proteins are called amino acids. Each protein you eat-say in a piece of bread –is made up of chains of amino acids. For this reason, amino acids are called the building blocks of proteins. When you eat a protein, your digestive system breaks it up into amino acids parts. There are 22 different amino acids found in nature, the protein assembly line of your body is able to make all but nine of these amino acids. These nine amino acids are called essential amino acids. They can only be obtained by breaking down the proteins of certain foods. The other 13 amino acids are called non-essential amino acids. Your body links the 22 amino acids together to build the proteins that make up cells, tissues and organs.

Sources of proteins: Most animal proteins, including lean eat, fish, poultry and eggs contain the essential amino acids and the non-essential amino acids you need. Such proteins are called complete proteins.
Vegetable proteins are incomplete proteins. They contain small amounts of one or another essential amino acids. An example of an incomplete protein source is soya beans. But by eating the right variety of vegetables, you can get all the amino acids you need.

Vitamins: In addition to substances that are used for building, repairing and fueling your body, you need small amounts of other materials to keep it running smoothly. Among these substances are vitamins. Vitamins help to regulate growth and the normal functioning of your body. Without a regular supply of certain vitamins, parts of your body can begin to function poorly. When your body does not get enough of a certain vitamin C may cause scurvy, a disease in which wounds take a longer time to heal. Your body only needs small amounts of vitamins. For this reason, vitamins are sometimes called micronutrients.

Your body needs about 13 kinds of vitamins. They fall into one of the two groups: fat-soluble and water-soluble. The fat-soluble vitamins are A, D, E and K. these can become toxic, or poisonous, if eaten too much. Vitamin C and the eight B vitamins make up the nine water-soluble vitamins. These vitamins cannot be stored by the body. Instead, they are constantly washed out of the adequate amounts in the food you eat each day.

The table, given below, lists the fat-soluble and water-soluble vitamins. It also lists which food contains them and explains the vitamins’ function in maintaining good health.

Minerals: Like vitamins, minerals help to maintain the normal functioning of your body. A Mineral is a very simple chemical substance found in nature. There are 16 essential minerals. Among these, important are sodium, calcium, phosphorus, iron and iodine. Deficiency of any one of them might lead to undesirable consequences.

Sodium: Sodium is associated with regulation of acid-base equilibrium and transmission of nerve impulses. The main source of sodium in our diet is sodium chloride (common salt NaCl, carrots, cauliflower, eggs, milk, nuts, turnip and radishes. Its shortage in your body may cause muscular cramps.