Chronic diseases - such as heart disease, cancer, and diabetes - are the leading causes of death and disability in the United States. Although common and costly, many chronic diseases are also preventable. Many chronic diseases are linked to lifestyle choices that are within your own hands to change. Eating nutritious foods, becoming more physically active and avoiding tobacco can help keep you from developing many of these diseases and conditions. And, even if you already have diabetes, heart disease, arthritis or another chronic condition, eating more healthful food and getting more exercise, whether it's a brisk walk, a bike ride, a jog or a swim, can help you better manage your illness, avoid complications and prolong your life.