Type 2 diabetes is a disease that develops when the body’s tissues cannot use insulin properly. Insulin is a hormone that helps the body’s cells use sugar (glucose) for energy. It also helps the body store extra sugar in muscle, fat, and liver cells. Over time, the pancreas cannot make enough insulin. Without insulin, the sugar cannot get into the cells to do its work. It stays in the blood instead. This can cause high blood sugar levels. A person has diabetes when the blood sugar stays too high too much of the time. Over time, diabetes can lead to diseases of the heart, blood vessels, nerves, kidneys, and eyes.