Cells need glucose from the bloodstream for energy. Diabetes occurs when blood sugar levels are too high due to insufficient insulin. There are two main types of diabetes: type 1 is caused by the immune system attacking the pancreas so it cannot produce insulin, while type 2 is more common and occurs when the body does not produce enough insulin or the cells do not respond properly to insulin, often due to lifestyle factors. Diabetes is managed through lifestyle changes like diet, exercise, and medication or insulin injections if needed to control blood sugar levels and prevent serious complications.