It’s not necessarily true that eating a low-fat diet will prevent heart disease.
While it is true that a diet high in saturated fat increases the risk of heart disease, some dietary fats protect against heart disease. Foods containing monounsaturated and polyunsaturated fats, such as olive or canola oil, nuts, fatty fish and flaxseed, may be beneficial to your heart.
Research has shown that diets with moderate amounts of monounsaturated and polyunsaturated fats lower the "bad" low-density lipoprotein (LDL) cholesterol and decrease the risk of heart disease and stroke. Choosing these healthier types of fat may be more important than restricting the amount of fat you consume each day.