Energy, food and healthy diet

Food is converted into energy in our bodies. Proper nutrition gives us proper amount of energy to cope with all our tasks. But why do we need energy?

There is simple experiment that shows one reason why energy is needed by the human body.

  • Measure and write down your body temperature.
  • How does your reading compare with the readings obtained by other people?
  • How do the results compare with normal human body temperature?
  • Measure room temperature by placing a laboratory ther¬mometer where the bulb is surrounded by air. Keep your hands well away from the bulb of the thermometer. After about two minutes, write down what the room tempera¬ture is.
  • Which is warmer, the air in the room or you?
  • What is the difference between the two readings?
  • In which direction will heat energy be travelling, from the air to you, or from you to the air?
  • If a beaker of hot water is left in the room, heat energy passes from the hot water to the air. What happens to the temperature of the water in the beaker. Does it rise, fall or stay the same?
  • You might expect the same to happen to human body temperature. Instead, it stays the same even though heat energy is being lost all the time. What must be going on all the time, in your body, to stop the temperature from falling as heat energy is lost?

So you see that the energy is needed to make heat. This heat replaces the heat that is lost by the body. It helps to keep body temperature constant at 37 °C. Energy is needed for other things as well.

Energy is measured in kilojoules. One kilojoule is the amount of energy needed to raise the temperature of 239 grams of water by one degree centigrade.

Energy requirements for A 25-year-old man, weighing 65 kg (10 stone), have such energy requirements: he needs 6 kilojoules per minute to just to sit, 7 to stand, 13 to walk slowly, and 38 to walk upstairs. A pregnant woman needs some extra energy.

Now let’s turn to measuring the amount of energy in a piece of food. When you eat food, such as a potato, you take in some of the energy captured from the sun. This energy was captured by the potato plant when it was growing. In order to make sure that we take in enough energy we must, therefore, find out how much energy there is in the foods which we eat and develop healthy diet for us. The average amount of energy taken in by an adult person is 8600 kj/day from from plant foods and 5200 from animal foods.

For most foods this is not easy to measure the energy that they contain. It requires the use of very complex equipment and very accurate measurements. However, a rough answer can be obtained for a peanut by setting light to it. The heat it produces is then used to heat up some water. The rise in temperature will give some idea of the amount of energy in the peanut.

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Common nutritional diseases

Have you ever thought about your diet? The majority of us eat a large variety of things without realizing what they actually are. Proper nutrition should contain contains a sufficient variety of foods. But as far as many people don’t eat properly, there is quite a number of nutritional diseases.

A few of them are caused by eating too much. But most are caused by a lack of something in the diet. One of nutritional diseases of this kind is malnutrition. It is caused by a general lack of food in the diet. Malnutrition is the result of a improper, poor nutrition. Malnutrition may cause serious ill-health and lead to much sickness.

Another is caused by eating too much food. Obesity (overweight) is widespread all over the world. An obese (overweight) person is more likely to suffer from heart disease than someone who is not overweight. Heart disease kills more people than any other disease in the developed countries of Europe and North America. Obesity is common in these countries, and causes more ill-health than all the vitamin deficiency diseases put together.

One more disease is caused by the lack of a substance called vitamin D in the diet. A lack of vitamin D causes the bones to become soft. The legs may bend under the weight of the body. This one is called rickets and belongs to the so called deficiency diseases.

Another deficiency disease is marasmus. Children with marasmus suffer from a general weakness and do not grow properly. They are more likely to suffer badly from the infectious diseases which healthy people can get over quite easily. These include coughs and colds, as well as childhood diseases such as mumps and chickenpox.

One more deficiency disease is caused by a lack of vitamin A in the diet, and can cause blindness.

Nutritional diseases may not actually kill those who have them. However, they do make their sufferers more likely to get other diseases.

What proper nutrition should contain

In our crazy world we have to live a crazy hectic life. We are into our careers, businesses and ambitions. But are we really into ourselves? What about our diet? Do we eat properly?

It is important to realize that nutrition that consists mostly of such foods as hamburgers, coca-cola, chips, hot dogs, fish fingers and so on are unhealthy. Our body suffers from fatty foods full of cholesterol and toxins. It desperately needs fresh fruits and vegetables as natural cleansers and a great source of vitamins. No wonder that with such a diet we often find our minds and bodies unable to cope with the pace.

Therefore, it is vitally important to eat healthy food. Scientists agree that proper nutrition should contain the right amount of each of the following:

  • Proteins. They help to make new body tissues during growth. They also help to repair or replace worn or damaged parts of the body. Proteins can be converted into carbohydrate and used to give energy.
  • Minerals and Vitamins. They are needed in small quantities. They help to control body processes such as respiration, and to keep the body healthy.
  • Carbohydrates. These provide energy. They can also be converted into body fat.
  • Fats. They provide energy and can also form body fat. They also help the body to take in some vitamins.
  • Fibre or roughage. This is a thread-like substance formed of fibres that is necessary for proper digestion.
  • Water. Water makes up about two thirds of a man’s body weight.

Most foods contain many of these things. For example, 100 grams of boiled potatoes contain 1.5 grams of protein, about 20 grams of carbohydrate, about 79 grams of water, and a rather small quantity of minerals and vitamins. It

In the end of it it is important to emphasize that different people need different amounts of energy. So the right amount of all these components is not the same for all people.

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