Diabetes is a disease that affects how the body uses glucose a sugar that is the body's main source of fuel. When you eat, Glucose from the food gets into your bloodstream, your pancreas makes a hormone called insulin, which helps the glucose get into the body's cells, and your body gets the energy it needs. Type 1 diabetes occurs when the pancreas fails to make enough insulin. And type 2 occurs when cells do not respond to the insulin.