How do humans digest food?

In this video, learn about the human digestive system and what happens to our food when we eat it.

There are three parts to digestion:

• Breaking food down into smaller and smaller pieces
• Absorbing the things our bodies need
• Getting rid of the waste our bodies can’t use

For humans, cooking food is a way of making it easier to digest. Imagine trying to eat hard, raw rice or potatoes!

Mouth

Teeth break food into smaller pieces and grind it up. Water in saliva helps turn food into a soft paste that is easier to swallow. Saliva also contains chemicals called enzymes. These break the food down into smaller molecules.

When we swallow, food travels down the throat through the oesophagus to the stomach.

Stomach

The stomach churns food around. More enzymes and acids break the food down even more. The acid can kill microorganisms that might make you ill. After about four hours in the stomach, food moves into the small intestine.

Small intestine

The walls of the small intestine are able to absorb the proteins, carbohydrates, fats and vitamins we need. These pass into your bloodstream and are carried around the body to where they are needed.

Learn about the role of protein, carbohydrates, fats and vitamins in our diet here: The food groups

Large intestine

Next is the large intestine which mostly absorbs water. This leaves waste called faeces that your body can’t absorb.

This is stored in the rectum until you are ready to push it out of your anus when you go to the toilet.