A short history of villainizing saturated fat

Teicholz: Endocrinology, Diabetes, and Obesity: dietary guidelines, food policy, polyunsaturated fat, saturated fat

Starting in the 1950s with Ancel Keys and his “Seven Countries Study”, the government recommendation against and war on saturated fat and cholesterol began. This became known as the “diet-heart” or “heart-lipid” hypothesis. In recent years it has, fortunately, fallen under heavy scrutiny — particularly regarding conflicts of interest (such as financial or other special interests).

Photo by Morgane Perraud on Unsplash

One of the biggest criticisms of the Seven Countries Study (SCS) is that it examined a non-random sample of countries, an allegedly “cherry-picked” population. Countries with high intakes of saturated fat — such as Germany, Switzerland, and France — were excluded from the study.

From Teicholz article:

“Ultimately, the principal limitation of the SCS data was that they could only show an association, not a cause-and-effect relationship. The results of the SCS have never been independently analyzed, and most subsequent studies using similar approaches have failed to confirm its conclusions....”

Conflict started in with Framingham Heart Study which found “no relationship” between incidence of coronary heart disease and diet. We should not that correlation does not imply causation — as implied by many publications suggesting “linked or related” issues. However, in order for causation to exist, there must be correlation as well.

The Framingham study leader did not publicly announce their findings until 1992 even though the study concluded in 1960. This is what we call “publication bias.” In a dietary context, it’s very hard to get pro-meat, pro-saturated-fat, pro-cholesterol, or other “non-standard plant-based narrative” research published. Some of this has to do with special interests of board members at organizations who are blatantly anti-meat (e.g. WHO and Harvard) and some of it has to do with who is funding a given project and has a vested interest in the results.

Since 1948 the American Heart Association (AHA) received $1.7 million (or $20 million in today’s dollars) from Procter and Gamble (the makers of Crisco vegetable oil) which resulted in “propelling what was a small group into a national organization” according to AHA’s own official history. This is clearly a financial conflict of interest.

Multiple reassessments have shown that while reducing dietary saturated fat intake does lower blood cholesterol, the changes do not correspond to lower risk of cardiovascular disease (ref., ref., ref., ref.).

As recently as 2020, the United States Dietary Guidelines Advisory Committee (DGAC) has continued to be lead by “numerous intellectual, financial, and even religious conflicts of interest.” The most recent review excluded 88% of the evidence; evidence which did not support the association between saturated fats and heart disease.

Teicholz concludes,

“The observed resistance against considering this new science by successive DGACs can potentially be seen as reflecting longstanding biases in the field and the influence of vested interests. Until the recent science on saturated fats is incorporated into the U.S. Dietary Guidelines, the policy on this topic cannot be seen as evidence-based.”

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Teicholz, Nina. A short history of saturated fat: the making and unmaking of a scientific consensus. Current Opinion in Endocrinology & Diabetes and Obesity 30(1):p 65-71, February 2023. | DOI: 10.1097/MED.0000000000000791