This document attempts to evaluate the strengths of the associations between dietary fat and the genesis of atherosclerosis; the kinds of evidence on which these associations are based; and the risks and benefits caused by changing the quantity and quality of dietary fat in the American diet. The role of dietary fat will be evaluated herein as a factor independent of such other putative dietary factors as I) total caloric intake, 2) quality and quantity of dietary carbohydrate, 3) intake of alcohol, and 4) intake of salt. The section on 'Cholesterol' points out the difficulties inherent in evaluating cholesterol independently of dietary fat. However, saturated fat foods (the putative factor to be discussed in this section) are characteristically rich in cholesterol; therefore, this section will consider fat and cholesterol as conjoint factors when this is appropriate.