Fats

Fat is an important nutrient because it gives us energy. The body stores energy as a layer of fat under the skin. This is called adipose tissue.

Composition of Fats

Fats are made from glycerol and fatty acids. Each glycerol is attached to three fatty acids. Glycerol and fatty acids contain the elements carbon, hydrogen, and oxygen. Fats contain a lot of carbon. This is why they give us so much energy.

1 gram of fat gives us 9 kilocalories.

Classification of Fats

Fats are classified into two groups:

Saturated Fats

(mainly from an animal source)

Unsaturated Fats

(mainly from a vegetable source)

Sources of Fats

	Saturated Fats come mainly from animal sources such as meat, eggs, milk and dairy produce e.g. cream and butter. There is a lot of saturated fat in butter, lard, suet and dripping.
Unsaturated Fats come mainly from plant and fish sources such as peas, beans and lentils (pulse vegetables), whole cereals, nuts, cooking oil, polyunsaturated margarine and oily fish.

Function of Fats

Fat insulates the body. A layer of fat under the skin prevents heat loss from the body.

Fat protects the delicate organs such as the kidneys and nerves. A layer of fat surrounds them.

Fats provide the body with heat and energy. This helps to keep the body at the correct temperature (37^oC).

Fat is a source of the fat-soluble vitamins.

RDA of Fats

50%

Saturated

50%

Unsaturated

The RDA of fats is for a combination of saturated fat and unsaturated fat in the daily diet. It is recommended that we eat 50% saturated fat and 50% unsaturated fat in our diet. People in the western world eat too much saturated fat and it is recommended that we cut down on our intake. We should also increase our intake of unsaturated fats.

Deficiency of Fats

Fat deficiency diseases rarely occur as fat is present in a wide variety of foods. However we should not eliminate fats completely from our diet because they are also a source of the fat - soluble vitamins.

To cut down on Saturated Fats

Grill rather than fry.

Use vegetable oil instead of hard fats for frying.

Remove visible fat from meat.

Look for hidden fats in the diet e.g. pastries and crisps.

Use low fat milk, cheese, yoghurt and mayonnaise.

ACTIVITIES
1. Use the Food Tables to find out the type of fat in meat.
2. Which type of meat has the highest fat content?
3. Which type of meat has the lowest fat content?.
4. Visit your local supermarket. Make a list of all low fat-foods available.
Make a note of prices and compare them with the high-fat equivalents.
5. Make a list of the foods that you ate today. Indicate which contain:
(A) animal fats
(B) vegetable fats
(C) no fat

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