Diabetes is a condition in which the blood glucose level cannot be controlled properly, so it can rise too high. There are two main types, with different causes.
In type 1 diabetes the pancreas does not produce enough insulin. It usually starts in childhood. It is treated with injections of insulin, usually at mealtimes, together with monitoring the blood glucose level and controlling the amount of carbohydrate eaten.
In type 2 diabetes the body cells no longer respond properly to insulin, so glucose stays in the blood after meals. It is linked to obesity, a poor diet and a lack of exercise, and it is more common in older people. It is treated first by a healthier diet, losing weight and taking regular exercise. Some people also need medicine, and some need insulin injections.