Introduction
Man needs balanced diet in order to stay healthy, balance diet is the suitable amount of nutrients and fibre in the body and these nutrients can be found in the food taken. The food taken in by man is used in three principle ways namely for energy, growth and replacement of body tissues. Food is broken down in cells during respiration to provide energy for daily activities and essential body chemical reactions. It also provide the raw materials for making protoplasm and so contribute, to the growth of cells and tissues and to the replacement of cells which dies e.g. red blood cells and the cells of the epidermis and other damages to body structures.
A balance diet is one that provides an adequate intake of energy and nutrients for maintainace of the body and therefore good health. A diet can easily be adequate for normal bodily function, yet may not be a balanced diet. An human diet contain fat, carbohydrate, protein, vitamins, minerals, water and fibre all in correct proportion, also these proportion vary for each individual because everyone has different metabolic rates and level of activity, although some of these substances have no energy value they do participate in chemical reaction or bodily function.
Carbohydrate
Carbohydrates contain the elements carbon, hydrogen and oxygen. The forms of carbohydrate in man’s diet are starch, sugar and cellulose. Food relatively rich in starch is rice, maize, wheat, bread. Sugar can be found in cake, biscuits, sweet and cellulose is found in all the whole- plant material eaten even though they were not digested by enzymes but play an important part in diet as dietary fibre. Carbohydrate are principally of value as energy giving food providing an average 17kj per grams and the excess of carbohydrate is stored as glycogen in the liver and the muscles or converted to fat and stored beneath the skin in fat depots.
Protein
The amino- acid Proteins contain the elements of carbon, hydrogen, oxygen nitrogen and sometimes or usually sulphur. Examples of food containing protein are meat, eggs, beans, fish, milk and milk products such as cheeses. Proteins are broken down by digestion to amino- acid which are absorbed into the blood stream and eventually reach the cells of the body are assembled to form the structural proteins of the protoplasm. Proteins are essential for growth and replacement.
Fats
Fat contain only carbon, hydrogen and oxygen like carbohydrates but in different proportions. They are present in foods such as animal fat, butter, cheese, milk and ground nuts. Fats are formed from glycerol and fatty acids. Although man can convert carbohydrates to fatty acid but there are some that cannot make and it is necessary to take it in the diet in order to supply these essential fatty acids. Fats, particularly animal fat, is needed for the fat- soluble vitamins A, D, E and K which is contain. Fats are used in making cell structures, particularly the membrane system or cell. They are also an important source of energy although they are less digested and absorbed than carbohydrate they have more than double energy value. They are also protecting some organs in the body.
Mineral ions
Apart from carbon, hydrogen, oxygen, nitrogen and sulphur present in carbohydrates, proteins and fats a variety of other element is needed for the chemical activities of the body and for construction of certain tissues. These elements are obtained from food where they are usually combined in organic molecules. An adequate supply of minerals is essential for good health. They are found in most body fluids and help in building the body and controlled how it works. Examples of minerals are:
Calcium
This element enters into the composition of bones as calcium phosphate and into the dentine of teeth
