Has your doctor said you have high cholesterol? Then you know you need to change your diet and lifestyle to lower cholesterol and your risk of heart disease. That's the essence of preventing heart disease. Your body needs a small amount of cholesterol to function properly. But we may get too much saturated fat and cholesterol in our diet -- and both raise levels of LDL 'bad' cholesterol. LDL cholesterol can cause plaque to build up in arteries, leading to heart disease. HDL 'good' cholesterol, on the other hand, helps clear bad cholesterol from your blood. You want to lower LDL cholesterol and raise HDL cholesterol, starting with your diet.