Diet can influence the changes in plasma lipoprotein concentrations that occur with exercise. Dietary factors alone, however, probably do not account for the lipoprotein profiles of physically active people. Whether exercise or diet exerts the dominant effect on lipids and lipoproteins depends largely on the level of exercise achieved and the total energy balance. More well designed research is required to examine the effect of diet on lipids and lipoproteins in people of different levels of physical fitness taking part in a variety of physical activities.