HDL (high-density lipoprotein) is sometimes called "good" cholesterol, because it helps move cholesterol out of your body. HDL is made mostly of protein and only a small amount of fat.
High levels of HDL appear to help protect against heart disease. A person who is at risk for heart disease may be advised to raise his or her HDL levels by eating a balanced diet, exercising and losing weight, and stopping tobacco use. Also, medicines may be used to raise HDL levels.
WebMD Medical Reference from Healthwise