Diet is routinely recommended as the primary strategy for the prevention and treatment of high blood cholesterol. The National Cholesterol Education Program (NCEP), the American Heart Association (AHA), and a host of other health and medical organizations have advocated a diet low in total and saturated fat and cholesterol for reducing risk of cardiovascular disease. What is the evidence supporting these guidelines and the expected efficacy of dietary treatment? There is growing awareness that despite well-documented rationale for the dietary approach, many eligible patients are not routinely prescribed dietary treatment, and among those who are, there is limited response. What are the obstacles in implementing effective dietary intervention for prevention of cardiovascular disease? What are both the theoretical and practical limitations to achieving long-term adherence to diet and what strategies have been shown to be most effective? A review of the data surrounding these diet-lipid relationships is presented along with recently tested and promising behavioral approaches to facilitating patient adherence.