A person may be very thin and physically active level and still have a high cholesterol level even while on a strict, low-fat diet. In this case, high cholesterol is caused by genetic factors and nothing else. For these people, only medication, along with their current diet and exercise regimen, can lower their cholesterol levels. When blood cholesterol levels are too high, the excess accumulates along the lining of arteries, which causes a buildup that can slow or completely block the flow of blood. This process is known as atherosclerosis.
Cholesterol is carried in the blood by substances called lipoproteins.
Cholesterol carried by a low-density lipoprotein, or LDL, is sometimes referred to as bad cholesterol. LDL cholesterol levels are of primary concern to your health care provider because LDLs deliver cholesterol to cells outside the liver, contributing to the buildup that can occur in your arteries. High HDL cholesterol levels are considered beneficial. How well diet and exercise reduce blood cholesterol levels depends on several things, including your initial blood cholesterol level, your genetic makeup, and how closely you stick to the diet. Reducing the amount of fat and cholesterol in the diet will reduce everyone s blood cholesterol levels to some extent.