Diabetes prevents the body from properly metabolizing sugar from food and using it as fuel in the body's cells. When you digest food, most of it is broken down into glucose, a type of sugar. The glucose is then transported in the blood to individual cells to burn for energy. Insulin, a hormone made by the pancreas, is needed to get the glucose into the cells — like a key that opens a door. In healthy people, the body automatically senses how much glucose is in the bloodstream and releases the right amount of insulin. In diabetes, the pancreas doesn't make enough insulin or the cells are resistant to the insulin, or both. As a result, the amount of glucose in the blood climbs too high while the cells starve for energy.  

Diabetes is a huge health problem in the United States. Some 25.8 million American adults and children have diabetes, and each year 1.9 million adults are newly diagnosed with this condition. About 5 to 10 percent of people with diabetes have Type 1. Sometimes called insulin-dependent or juvenile-onset diabetes, this form of the disease typically strikes in childhood or young adulthood. It is caused by a failure of the pancreas to produce insulin, perhaps because of autoimmune disease, genetic abnormality, or injury. People with Type 1 diabetes must take insulin shots.

Type 2 diabetes is far more common, and affects 90 to 95 percent of people with diabetes. It is often linked to obesity and lack of physical activity. In the past, this form of the disease was called adult-onset diabetes, but today more and more children are being diagnosed with Type 2 diabetes.