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Dietary fat

Dariush Mozaffarian, MD, DrPH
Section Editors
Mason W Freeman, MD
Timothy O Lipman, MD
Deputy Editor
Daniel J Sullivan, MD, MPH


The chief concern about dietary fats is their role in promoting coronary heart disease; other concerns relate to their possible roles in the genesis of obesity and cancers. Despite decades of research, however, the relationship between fat intake and these health outcomes is not entirely clear. While recommendations from several authoritative United States organizations over the past two decades have emphasized decreasing the total amount of fat in the diet, most research indicates that the type of fat is more important than total fat.

Issues regarding dietary fat are reviewed here. The management of patients with hypercholesterolemia and the role of diet and dietary supplements in lipid lowering are discussed separately. (See "Management of elevated low density lipoprotein-cholesterol (LDL-C) in primary prevention of cardiovascular disease" and "Lipid lowering with diet or dietary supplements".)


There are several reasons to be circumspect regarding strong recommendations to reduce total fat intake to below 30, or perhaps even 35, percent of energy. First, the evidence that a high total fat intake is harmful is weak [1]. Furthermore, the recommendation to limit fat intake was based upon research of its effects on total blood cholesterol [2]. The subsequent emphasis on fat intake has thus tended to limit our vision of a disease-protecting diet to those factors which affect atherosclerosis. We are now aware of many other pathways by which components in the diet can affect not only atherosclerosis, but also thrombosis as well as other chronic diseases of adulthood. Such factors include the quantity and quality of the other macronutrients (carbohydrate, protein), antioxidants, folate and its cofactors, and other vitamins and minerals.

Other issues with regard to the recommendation for a low-fat diet include:

The role of dietary fat in the etiology of obesity is unclear.

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Literature review current through: Oct 2017. | This topic last updated: Jan 03, 2017.
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