Diabetes is a disease in which the body's blood glucose, or blood sugar, level is too high.
Normally, the body breaks down food into glucose and then carries it to cells throughout the body. The cells use a hormone called insulin to turn the glucose into energy. The two main types of diabetes are type 1 and type 2. In type 1 diabetes, the body doesn't make enough insulin. This causes the body's blood sugar level to rise. In type 2 diabetes, the body's cells don't use insulin properly (a condition called insulin resistance). At first, the body reacts by making more insulin. Over time, however, the body can't make enough insulin to control its blood sugar level.