Do you eat a balanced diet?
It is never still inside your body. There is always something going on. In fact there are many different things going on all at the same time. Your body is made from trillions of cells. They are so small that you need a microscope to see them. If you looked at some of your body cells with a microscope, you would see that they looked like tiny boxes. Inside each one, changes or processes are taking place, which keep the cell alive. These processes need a supply of materials and energy. They get this supply from the food you eat.

Most parts of a cell are made from protein so when they wear out they need new protein from the food to replace them. In some parts of the body, new cells are continually being made so protein is needed to construct them. Two of these places are just beneath the skin and in the lining of the mouth, stomach and intestine. The new cells are made to replace the ones that are worn away. For example, when you rub your hand across a table you leave a microscopic trail of dead skin cells behind. The new cells under the skin surface replace them. As you chew your food, it rubs against the inside of your mouth and pulls away the lining. Cells beneath the lining divide to make new lining cells.

Fat is needed to make the walls of the cells so it is needed wherever cells are repairing themselves, growing or dividing to make new cells.

Some cells need other chemicals, called minerals, to help them perform their tasks in the body. Red blood cells need the mineral called iron. It allows the cell to make a special chemical called haemoglobin. This chemical allows the red cells to pick up large amounts of oxygen and carry it round the body to all the places where it is needed. The cells, which make the bones and teeth, need a mineral called calcium. This forms a tough material, which gives bones and teeth their strength.

With all the building and repair work going on, the cells need all the help they can get. Extra help is provided by vitamins. For example, vitamin A helps to form moist linings in the nose and airways to keep out germs. Vitamin C helps the cells in tiny blood vessels hold together and vitamin D helps calcium become locked into bones and teeth.

All activities of the cells need energy. This is provided mainly by carbohydrates but some is also provided by fats. Carbohydrates are the main fuels of the body because they break down quickly to release their energy. Fats are usually stored because they release their energy more slowly. This is particularly useful when there is less energy in the diet than the body needs.

You may wonder where the energy in food comes from. The answer is that it comes from a place one hundred and fifty million kilometres away - the centre of the Sun. Here, hydrogen gas is squashed so hard that it turns into helium gas and produces energy as heat and light. When some of the sunlight reaches the Earth it is trapped in the leaves of plants. In the leaves, the energy is used to make sugar and starch. In some plants fats and oils are also made. When animals feed on plants they convert some of the carbohydrates they eat into fat. So when our body uses the energy from carbohydrates and fat in our foods it is really using power from the Sun.

In the body the five food groups come together to provide all the needs of the cells. The body only needs certain amounts of food daily. If it receives too little nourishment, growth and repair will stop and the body's health will be threatened. If the body receives too much nourishment, health may also suffer. There is a trick to be learned by everyone. It is a balancing trick. To perform this trick, you have to supply your body with just enough of all the food groups for your body's needs. If you can perform this trick, you will be eating a balanced diet.

What happens to the cells that break off from the lining of your mouth?
You swallow them with your food. They are digested and some of the proteins and minerals in them may be used again to make new cells.

What happens to the body if it does not get enough energy in food?
The body will use up its stores of fat to provide energy to keep the cells alive. When they are used up it may even break down some of the muscle tissue to release more energy but by this time the body is dangerously thin and the person may soon die. These conditions occur in the bodies of starving people. That is why it is important to get food to areas where people are starving so they can receive enough energy to keep them alive.

Children who eat a diet which is low in energy, protein and minerals only grow very, very slowly and have little defence against disease. That is why they are given priority when food is being distributed to starving populations.

Some children in areas where people are starving have fat stomachs. Why is this?
They have swollen stomachs not fat stomachs. These children are suffering from a disease called kwashiokor. It is due to a lack of protein in the diet. When the children were babies they received their protein from their mother's milk. When they began to eat solid food there was not enough protein in their diet because food was scarce so their stomachs became swollen. The children's stomachs tend to look large compared to their arms and legs because the muscles in the arms and legs waste away when there is a lack of protein in the diet.

Can you have a balanced diet without eating meat?
Yes. Some people, called vegetarians, prefer not to eat meat. They receive all the proteins they need from milk, cheese and eggs. Peas, beans and lentils are good sources of proteins from plants so vegetarians eat more meals with these foods in them,

How is the body affected if it does not get enough iron?
A disease called anaemia develops. The lack of iron means that the blood cannot carry enough oxygen round the body. Oxygen is needed by the cells to release energy in food. As the body cannot release enough energy for a full active life, an anaemic person is tired, listless and feels weak.