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FOOD
WHAT IS FOOD?
Why do we eat?
1. Most children would answer this question by saying: ‘We eat because we like
eating’ – TRUE.
2. A starving person would say: ‘I want to eat because I am hungry’ – TRUE.
What would happen if we do not eat?
We would die. Which means of course that we eat to live?
What do we eat?
That is easy. We eat FOOD. Do drinks count? Very often it does.
What is food?
Food is any solid, semi-solid or liquids which when swallowed provide the body
with materials enabling it to carry out one or more of the following functions:
1. Growth and repair
2. Energy production (including the liberation of heat)
3. To regulate the health of the body, maintaining normal body processes and
prevents diseases.
Examples of food
Solid food
: boiled egg, cakes, cooked chicken/fish, etc
Semi-solid food : oat/rice porridge, puree, yoghurt, Soya bean custard (taufu fa)
Liquid food
: fruit drinks, milk, Soya milk, soup, sauce (kuah)
Sources of Food
1. Plants take in carbon dioxide from the
air through their leaves and absorb
water with dissolved mineral elements
from the soil through the roots.
2. The green colouring matter in the
leaves, chlorophyll enables the leaves
to absorb energy from the sun.
3. This energy is used to convert carbon
dioxide and water into carbohydrates.
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These together with mineral elements form the plants.
4. Animals either feed on green plants (they are herbivorous – animals feeding on
grass) or prey on other animals (they are carnivorous – animal feeding on
animals) but they are also dependent in the first instance on plants for their food.
5. Man is both herbivorous and carnivorous i.e. omnivorous.
Note: A mixed diet is best for most people.
NUTRIENTS
1. All food is made up of chemical substances called nutrients.
2. Each nutrient has its own special job to do to help the body stay alive and healthy.
3. The names of the nutrients are:
(a) Protein
(b) Carbohydrates
(c)
Fats
(d) Vitamins
(e) Minerals
(f)
Water
4. The general functions of the nutrients are:
(a) Proteins – Provide materials for body growth and repair. Excess proteins
can be used as energy when the body is short of energy food (carbohydrate
and fat).
(b) Carbohydrates – Provide energy which is needed for all bodily activities.
Some energy is liberated (released) as heat.
(c)
Fats – Functions are the same as carbohydrates and they also act as
insulators when stored in fatty tissues.
(d) Vitamins – They assist resistance to diseases and regulate body processes.
They help the body use food for energy, growth and repair.
(e) Minerals – Minerals provide materials for growth and repair and
regulation of body processes.
(f)
Water – It forms a large proportion of all body material (cells, blood). It is
needed for various secretions (saliva, bile juice, digestive juice) so it may be
classed as a regulator. It also transports materials within the body.
Note:
Roughage (cellulose/dietary fibres/Non-starch polysaccharide) cannot be digested
so it is not a nutrient but needed to aid digestion.
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What is nutrition?
When we eat, nutrients in the food are absorbed by the body. The study of the
effects these nutrients have on the body and how the body uses nutrients is known
as nutrition.
When we have a well-balanced diet, we take into the body all the nutrients it
requires in the correct amounts or proportions and with sufficient water and
dietary fibres. This means the body enjoys good nutrition and will stay healthy.
On the other hand, an imbalance in the diet can lead to malnutrition. This happens
when there is insufficient or excessive nutrient in the diet and the body suffers.
Not having enough to eat or having a diet that is lacking in certain nutrients can
result in under-nutrition.
An excessive intake of a particular type of nutrient even
though the other nutrients are present in sufficient
amounts is also harmful to the body. This is overnutrition. For example, taking in too much of fatty foods
could lead to health problems like obesity and heart
diseases.
Is there a food which will give us all these nutrients?
1. No, there is not. Some food will give us only one
nutrient and some foods will give use several nutrients.
2. In order, to have all the nutrients we must eat a mixed diet. But our body need
only certain amount of each nutrient regularly.
3. Our body needs a mixed diet which contains the right amount of all the nutrients.
This is called a balanced diet.
What happens if we have too much of a certain nutrient?
1. In food
: within limits, the body would use it or get rid of the extra.
2. In medicines : it could be dangerous.
(a) The correct dose should only be taken.
(b) All vitamin tablets, iron tablets, etc. should be kept out of
mall children’s reach.
What happens if we have too little of a certain nutrient?
1. The body would manage for a time.
2. After a time, the body would become ill or even die.
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