What is the main cause of diabetes?

The main cause of diabetes is insulin resistance. This occurs when the body's cells do not respond to insulin as well as they should. Insulin is a hormone that helps glucose, or sugar, get from the blood into the cells. When the cells do not respond to insulin, glucose builds up in the blood, leading to high blood sugar levels. Type 2 diabetes is the most common form of diabetes and it is typically caused by insulin resistance.