- A disease that occurs when the body is not able to use sugar as it should. The body needs sugar for growth and energy for daily activities. It gets sugar when it changes food into glucose (a form of sugar). A hormone called insulin is needed for the glucose to be taken up and used by the body. Diabetes occurs when the body cannot make use of the glucose in the blood for energy because either the pancreas is not able to make enough insulin or the insulin that is available is not effective. The beta cells in areas of the pancreas called the islets of Langerhans usually make insulin. There are two main types of diabetes mellitus: Type 1 (insulin-dependent): the pancreas makes little or no insulin, because the insulin-producing beta cells have been destroyed. Treatment consists of daily insulin injections or use of an insulin pump, a planned diet, regular exercise and daily self-monitoring of blood glucose. Type 2: the pancreas might make some insulin, but it is not effective (see Insulin Resistance). Type 2 is controlled by diet and exercise and daily monitoring of glucose levels. Sometimes oral drugs that lower blood glucose levels or insulin injections are needed.