Type 2 diabetes mellitus (adult-onset diabetes) interferes with the body's ability to store energy from food, resulting in high blood sugar levels that can lead to problems, such as kidney failure, blindness, and heart disease. Insulin helps the body to convert food to stored energy and keeps blood sugar levels within the normal range. In type 2 diabetes, body tissues are resistant to the effects of insulin and patients lack effective insulin levels that are required to keep their blood sugar levels normal. Some patients can overcome the abnormalities by taking prescription pills, while others must take insulin injections at least once daily. Researchers have been exploring ways to give insulin to diabetic patients other than by injection. One alternative is inhaled insulin, whereby patients breathe insulin into their lungs by using a special device.