Provides twice the energy of carbohydrates (1 gm provides 37 kJ or 9 kcal of energy) (i.e. 2.25 times more energy than carbohydrates).

Acts as the reserve food material because excess fat is stored in the liver and as adipose tissue.

As the fats produce more energy on oxidation than glycogen, they are more suitable as stored food.

Stored fat is used as fuel when glucose is not available.

An enzyme called Lipase digests fats. It breaks down into fatty acids and glycerol.

There are 2 types of fatty acids : Saturated and Unsaturated.

  • Saturated Fatty Acids : Solids at room temperature.
  • Unsaturated Fatty Acids : Liquids at room temperature.

Our diet should contain less saturated fats, such as butter, ghee and hydrogenated vegetable oils, than unsaturated fats, such as simple vegetable oils.

Excess of saturated fats increases the blood – cholesterol level and may cause arteriosclerosis (hardening of arteries).
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This may lead to heart attack.

Man can synthesize most of the fatty acids his body needs from the fatty acids present in the food taken.

A few fatty acids are not synthesized, and must be present in the Diet. They are called essential Fatty Acids.

They include Linoleic, Linolenic and Arachidonic Acids.

They are present in unsaturated Fatty Oils such as Groundnut Oil, Sunflower Oil, etc.

Hydrogenation : Process by which unsaturated fatty acids are converted into saturated fatty acids by the addition of Hydrogen.

Requirement : 50 gms daily.

A person should draw 10 – 15% of total calorie requirements from fats.

Note :
In whales and seals, the fat of the skin forms a thick layer called blubber which is not only reserve food but also maintains the body temperature.

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