Diabetes is a chronic disease associated with metabolic disorders in which blood glucose (sugar) levels are constantly elevated due to a lack of insulin or immunity to it. The main types are 1 (lack of insulin, often in young people) and 2 (insensitivity to insulin, associated with obesity and lifestyle). Symptoms: extreme thirst, frequent urination, fatigue, weight loss, poor wound healing. Complications can affect the heart, kidneys, eyes, and nerves, so treatment involving diet and medications is important.