Type 2 diabetes
Usually, blood sugar levels are regulated by insulin, but in type 2 diabetes this does not work properly. Insulin is a hormone which tells the muscle and fat cells of the body to take up sugar from the blood. If there is too much sugar in the blood for a long period of time, the muscle and fat cells start to ignore insulin. As a result, sugar stays in the blood and is not taken up, leading to a high blood sugar.