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.