There are two types of diabetes - type 1 and 2. Both result in the level of sugar - or glucose - in your blood becoming too high. For type 1 patients this happens when your body cannot produce enough of a hormone called insulin, which controls blood glucose.
For type 2 diabetes, which is much more common, raised blood sugar levels are usually caused by being overweight or not exercising enough.
Patients with either type need to be careful about controlling their blood sugar.