The Third Report of the National Cholesterol Education Program's Adult Treatment Panel (ATP III) has an extensive section on nonpharmacologic therapy for those with abnormal blood lipids. ATP III focused on the high-saturated fat atherogenic diet, obesity, and sedentary lifestyle and recommended a program of therapeutic lifestyle change (TLC). This review discusses several issues, including 1) why ATP III changed from the Step I and Step II diets to TLC; 2) the benefits of keeping trans fatty acid intake low and the addition of viscous fiber and plant stanol/sterol esters to reduce low-density lipoprotein cholesterol beyond that seen with the Step II diet; 3) the de-emphasis on total fat and a sharper focus on the kinds of fat ingested in the new guidelines; 4) the endorsement of regular physical activity and weight loss as important first steps in reversing the unwanted metabolic effects of the metabolic syndrome; and 5) the emphasis of health-promoting aspects of the diet that include, among other things, fish and omega-3 fatty acids. At all stages of TLC, ATP III encourages the referral to registered dietitians or other qualified nutritionists for medical nutrition therapy. TLC and the ATP III guidelines should provide guidance to practitioners who wish to get low-density lipoprotein cholesterol to goal (whether or not drugs are used), prevent or treat the metabolic syndrome, and improve the overall health of the patient.