Insulin resistance is a serious condition in which insulin becomes less able to lower the level of glucose (sugar) in the blood. Usually, insulin helps sugar move out of the blood and into the body's cells. In the cells, the body can use sugar to make energy. If this does not happen correctly, too much sugar stays in the blood. This is called hyperglycemia. If the blood glucose level is above normal for a long time, this can lead to major health problems. 