When we eat food, the carbohydrates (sugars) that we eat are broken down in our digestive system to produce glucose. This glucose has an important role to play in our health, as it is required to provide the energy our cells need to live and function.

If we don't have enough glucose we are at risk from harmful conditions like diabetic ketoacidosis which can be life threatening. On the other hand, often we eat too much sugar and have too much glucose in our blood.

This is bad news for us, because too much glucose damages our cells and organs, causing them to not work so well. So, it is really important that our bodies are able to control the amount of glucose is our blood.