Coronary heart disease (CHD) stems from the interplay between genetic and environmental factors. However, modifiable environmental factors, especially diet and lifestyle, are largely responsible for increased risk of CHD at population levels. Although cigarette smoking, obesity, and physical inactivity are well-established causes of CHD, the role of specific dietary factors has not been clearly defined until more recently. Cumulative evidence indicates that types of fats and carbohydrates are more important than total amounts in determining risk of CHD. Epidemiologic and clinical trial data strongly support that dietary patterns rich in fruits, vegetables, whole grains, and nuts can reduce risk of CHD. Diet and lifestyle modification, combined with pharmacologic treatment of hypertension and high lipid levels (if necessary), could prevent the vast majority of CHD events.