2.3 Carbohydrates and lipids

2.3 Carbohydrates and lipids

Carbohydrates and lipids are both sources of energy that the body uses. Your body will rely on both as a source of energy.

What is the difference?

Complex carbohydrates eg. glycogen. Can be broken down relatively rapidly to form single sugars, like glucose. They store less energy per gram than lipids. Glycogen, the human carbohydrate used for energy storage, requires water to help store it, which makes it less efficient as an energy store per weight. In summary, they are a good short-term energy store.

Lipids, eg. cholesterol and triglycerides. Cannot be mobilised rapidly, it takes time to break them down. They store far more energy per gram than carbohydrates (about 6 times more). They do not require water to help store them, which makes them more efficient as an energy store per weight. In summary, they are a good long-term energy store.

AND unlike complex carbohydrates, in humans they also have secondary uses:

– thermal insulation in the sub-cutaneous adipose tissue (fatty tissue underneath skin keeps us warm).

-Shock absorption for major organs (all of our major organs have a layer of fat to protect them)

-Waterproofing and conditioning (sebum, natural oil found on human skin and in human hair).

Breaking down and Building carbohydrates and lipids

In order to get the energy from complex carbohydrates and lipids, we need to break them down. In order to store the extra energy in our food, we need to build them.

1) Anabolic reactions – build, remove water.   2) Catabolic reactions – destroy, add water.

Both types of reactions depend on enzymes to help them work faster (catabolic reactions rely on digestive enzymes, eg. amylase, which breaks down amylose (a kind of starch), into maltose ( a double sugar).


Lipids diary: Analysis



2.3 Optional  Project: ‘ Superhealth Me’


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