There are two main types of diabetes: type 1 and type 2.
Type 1 diabetes is where you are unable to produce any insulin. It can develop at any age but usually appears before the age of 40, and especially in childhood.
It's treated by daily insulin injections, a healthy diet and regular physical activity.
Type 2 diabetes develops when the body can still make some insulin, but not enough, or when the insulin that is produced does not work properly.
It usually appears in people over the age of 40. But in south Asian and black people, who are at greater risk, it often appears from the age of 25.
It is also getting more common in children, adolescents and young people of all ethnicities.
Type 2 diabetes is treated with a healthy diet and increased physical activity. In addition to this, medication and/or insulin is often required.