Certain lifestyle choices can affect your levels of low-density lipoprotein, or LDL, greatly increasing your risk for heart disease and heart attack. Commonly referred to as "bad" cholesterol, LDL is one of two types of lipoproteins that carry cholesterol to and from your body's cells. LDL is considered "bad" because it contributes to plaque, a thick and hard deposit that can build up on arterial walls, clogging arteries and making them less flexible. Clogged, inflexible arteries can obstruct blood flow to the heart, increasing a person's risk of heart disease and heart attack. Smoking cigarettes, maintaining a poor diet that's high in saturated and trans fats, weight gain that results from eating too many calories, excessive alcohol consumption and a sedentary lifestyle are all unhealthy lifestyle choices that contribute to high LDL levels and put people at significant risk for heart disease, heart attack and stroke.