Diabetes is a serious medical condition characterized by high levels of glucose in the blood.

Glucose is a simple sugar that comes from the food you eat. When your stomach digests food, glucose is absorbed into the bloodstream. The glucose circulates in your blood and serves as the main source of fuel for all the cells in your body.

However, glucose cannot get inside cells by itself. Glucose needs insulin, a hormone produced by the pancreas, to transport it from blood into cells.

Diabetes occurs when the pancreas either can't produce any insulin at all, can't produce enough insulin, or the body can't use the insulin it makes. When any of these happens, glucose builds up in the blood. This is a condition known as hyperglycemia. The result is that the body lacks the fuel it needs.

• Type 1 diabetes -- Usually starts in childhood and accounts for 5 to 10% of all diagnosed cases of diabetes. Type 1 diabetics produce little or no insulin and therefore must use insulin daily to control their condition.
• Type 2 diabetes -- Usually starts in adulthood, and many of these people don't even know they have diabetes. It is much more common than Type 1, accounting for 90 to 95% of cases. Type 2 diabetes is often controlled with diet and exercise, and sometimes oral drugs or insulin.
• Gestational diabetes -- Some women develop this form of diabetes when they are pregnant. Gestational diabetes usually goes away after the baby is born, but the woman is then at higher risk for developing Type 2 diabetes later in her life.