Insulin resistance is a condition in which body cells do not fully respond to the action of insulin, a hormone that controls the amount of sugar (glucose) in the blood. As a result, blood sugar levels become abnormally high.

Over time, insulin resistance can result in consistently high blood sugar levels, which increases a person's risk for type 2 diabetes. Pregnant women who are insulin resistant have an increased risk for gestational diabetes.

Usually, insulin resistance develops in people who are overweight and not physically active. These characteristics are often associated with having high cholesterol and high blood pressure. People who are insulin resistant have an increased risk of heart disease and stroke, especially if other risk factors, such as being a smoker or having high cholesterol levels, are present.