Food can be divided into four general categories as follows:
1. Carbohydrates and fats provide our body with its energy requirements. The greatest amount of energy consumed goes into maintaining the correct body temperature. In fact, about seventy five percent of the energy in the body is required for this purpose, depending on the climate. The remaining energy is utilized by the muscles throughout the body, whether for the internal organs such as the heart, lungs, etc., or for the outer limbs such as the arms or legs. Fats also form protective layers which shield the delicate body organs from injury and allow storage of energy for future use. However, over-consumption of these foods leads to overweight. Butter and oils are almost pure fat, while refined sugar is practically one hundred percent carbohydrate. This latter category also includes food such as potatoes, rice and bread, which are predominantly carbohydrate, containing very little fat.
2. Proteins are the remarkable materials from which new cell tissues are built. Proteins are needed to repair worn-out tissues, as well as being essential to growth and muscular development. They are also necessary for the production of special substances that build up the body’s immunity. There are large numbers of different proteins, all of which perform a definite role. Proteins are needed by everyone, but are required in greater quantities during childhood, adolescence, pregnancy and lactation, or any time the body is constantly expending a lot of energy.
Proteins are an essential part of our diet and are abundantly present in such foods as milk, cheese, meat, fish, eggs, grains, beans, lentils, nuts, etc.
3. Mineral salts are yet another category of the essential elements required by the body. They are present in minute quantities but are nevertheless vital in the maintenance of correct body functioning. The kinds of mineral salts present in the body are numerous and varied, with each carrying out diversified functions. Some, such as phosphorus and calcium, are necessary for the building of strong teeth and bones. Phosphorus is also essential in the functioning of the brain cells. These two minerals are found in green vegetables, cheese, soya beans, potatoes and fish.
Iron, which is needed in greater quantities by women than men, is important in the production of haemoglobin, a protein in the blood cells. Without iron the blood is unable to transport oxygen throughout the body and so unable to perform its duties. The best sources of iron are meat, eggs, raisins, spinach, whole grain cereals, liver, apricots and potatoes.
In the body there are only a few grains of iodine, yet it is one of the most important minerals. The majority of iodine absorbed by the body is utilized by the thyroid glands in the production of thyroxine, which is essential in regulating the body metabolism. It also directly controls the growth rate of the body and as such is especially needed during pregnancy, childhood and adolescence. Iodine is found in iodized salt, seafood and vegetables.
Salt in the form of sodium chloride is also essential for the maintenance of the normal acid-base balance in the body. Without it we could not live. Remember, however, that too much salt tends to raise the blood pressure and causes swelling in the legs. So a moderate amount of salt is recommended, although during warm weather the intake should be raised.