Lowering total cholesterol in the diet is a start, but new studies released recently indicate that's not enough to prevent heart attacks. Knowing the difference between "good" cholesterol and "bad" cholesterol may help reduce the risk of cardiovascular disease and heart attack.

A study conducted by the Indiana University School of Medicine revealed that it may be more important to keep good cholesterol high than to lower bad cholesterol – even if it means overall cholesterol levels are high.

All cholesterol – that fat-like substance produced by the body and consumed in meat, poultry, fish, eggs and dairy products – is not created equal. The good cholesterol, needed by the body to make hormones and vitamin D and to produce bile (which breaks down other fats), are called high-density lipoproteins (HDLs). HDLs are found in monounsaturated fats like olive oils, vegetable oils, nuts and avocados.

Diets high in fruits, vegetables, nuts and grains are heart healthy. They increase good cholesterol without significantly increasing total cholesterol. The National Cholesterol Education Program guidelines suggest an HDL goal of 45 milligrams per deciliter (mg/dL) or higher for men and 55 mg/dL or higher for women.

Also, HDLs help the body break down the bad cholesterol, or low-density lipoproteins (LDLs). LDLs have more fats than proteins and contribute to plaque formation in the arteries. Optimal levels of LDLs should be kept below 100 mg/dL. Foods high in saturated and trans fats (butter, stick margarine, lard, red and fatty meats, cheese and other dairy products) are loaded with LDLs.