At least half of the energy we consume should come from carbohydrates and it is better to get carbohydrates from starchy foods instead of sugary foods as they can rot your teeth.

Function.
Provides us with energy.

Sources.
There are two main sources of carbohydrates: starchy foods e.g. potatoes, rice and cereals. The other main source is sugary foods e.g. jam, chocolate and syrup.