Type 1 diabetes is when the body does not make enough insulin. Insulin is a hormone that helps your body convert food into energy. Without insulin, glucose (sugar) from the food you eat cannot enter cells. So glucose builds up in the blood. Your body tissue becomes starved for energy.
Type 1 diabetes usually begins in children and young adults. Over the long-term, if type 1 diabetes is not adequately treated, high blood sugar levels can damage the blood vessels, heart, kidneys, eyes, nerves, and other tissues or organs.