Tracy Severson, Penny M Kris-Etherton, Jennifer G Robinson, John R Guyton

This roundtable discussion on dietary fats was inspired by a recent Presidential Advisory from the American Heart Association giving recommendations about dietary fats for prevention of atherosclerotic cardiovascular disease. The Advisory clarifies a long-held position that saturated fat should be reduced in the American diet. New studies and meta-analyses have questioned the adverse role of saturated fat. The Advisory adds a crucial clarification based primarily on 4 randomized controlled diet trials, each conducted over 4 to 8 years during the 1960s extending to the 1970s. In each trial, saturated fat was reduced and replaced by vegetable oil rich in polyunsaturated fat (PUFA). Meta-analysis showed 29% reduction in major coronary events in the groups receiving PUFAs. Randomized clinical trials provide the best kind of evidence. Replacing saturated fat with PUFA reduces cardiovascular events. Replacing saturated fats with carbohydrates or trans fats does not reduce cardiovascular events. Cardiovascular risk reduction has also been seen in randomized trials with monounsaturated fat in the context of whole food diets, mostly plant based (Mediterranean diets). In this discussion, we additionally cover some of the roller-coaster history of recommendations concerning dietary fat and provide advice for practical counseling.