Diet-Heart Hypothesis

Keys used the same disparaging arguments to dismiss observations of Inuit in the Arctic. Like Mann, Vilhjalmur Stefansson had also seen for himself how good health and a high-fat diet could go hand in hand; the Inuit diet, as we’ve seen, was at least 50 percent fat. And in 1929 Stefansson conducted that yearlong experiment of eating only meat and fat. Optimistically, he expected that these efforts would lead to “a path of garlands for the high-fat regimens” laid down by admiring colleagues. He was thus unprepared for his fall from grace. “And what a fall!” he wrote. “The first cloud in the sky was no bigger than a man’s hand, in fact no larger than a brief and friendly personal note from Dr. Ancel Keyes [sic]” in 1954.

A notable early example of this enduring controversy was “Keys versus Pickering”. The venue was the World Health Organization, and the year was 1955. There and then, Ancel Keys put forward his ideas expecting to be accepted on the spot, but he was challenged by Sir George Pickering, who according to witnesses said, “Yes, and Professor Keys would you be kind enough to cite for us the principle piece of evidence that you think supports this diet-heart theory of yours?” Keys’s evidence, at that time, was not convincing and his hypothesis was not accepted, which drove him to build the evidence that would allow him to prove his point.

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Health revolutionary: the life and work of Ancel Keys, (Documenting Public Health Leadership project of the Associations of Schools of Public Health and the Health Resources and Services Administration), DVD. Minneapolis, MN: University of Minnesota Schoool of Public Health, 2002

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"The pivotal moment in Keys life -- Keys got up from being knocked around and said 'I'll show those guys'...and he designed the Seven Countries study." - Nina Teicholz - TBFS - Page 36

The next year an article by Yerushalmy and Hilleboe appeared in what was a direct, and for Keys, painful sequel to the Geneva meeting. We learn from their footnote that: “The authors became interested in this question (diet vs. national mortality data) during a meeting of a WHO study group on atherosclerosis and ischemic heart disease in Geneva, Switzerland, November 1955. At that meeting statements were made about the association between heart disease and mortality and fat in the diet. As it later developed, these were based on a few selected countries and were of questionable validity. On their return to the United States, the authors reviewed the available data carefully, and the results indicated that the subject required further study.”

I recall well the reaction in Minnesota and in epidemiological circles to this article and the challenge it represented for proponents of the diet-heart idea. The article seemed to magnetize the pre-existing polar elements of the scientific community: the lines of force were drawn. Meanwhile, proponents were already reviewing data from several North American cohort studies showing the short-term predictive relationship of serum cholesterol level in health to risk of subsequent coronary events. Moreover, several investigators were involved in feeding experiments of the effects of fatty acid composition of diet on serum cholesterol level. Keys, meanwhile, had made new comparisons of diet and blood lipids among casual samples of men in South Africa and Japan, to test the relation in contrasting populations.

The tone of the Yerushalmy-Hilleboe “methodologic note” was authoritative, pedantic, and patronizing, beginning with: “The evidence which has been presented for the existence of a relationship between diet and heart disease, however, is, for the most part, derived from indirect methods of study. In these indirect methods the primary unit of observation is the group; in the direct method the primary unit of observation is the individual. . . .It is well known that the indirect method merely suggests that there is an association between the characteristics studied and mortality rates and, further, that no matter how plausible such an association may appear, it is not in itself proof of a cause-effect relationship.”

The authors go on to editorialize and scold the naïve: “The quotation and repetition of the suggestive association soon creates the impression that the relationship is truly valid, and ultimately it acquires status as a supporting link in a chain of presumed proof.” After admitting, however, that such an indirect method of study may be valuable, they again wax pedantic: “unfortunately, however, if you superficially accept and do not properly augment it, the indirect method has many weaknesses. The most serious is the fact that the apparent association often proves to be the result of non-pertinent extraneous factors. Therefore, it is always necessary to probe further, to go beyond the simple, apparent association and to investigate related variables.”

Dietary Fat Recommendations

1957:

• 25-30% of calories from total fat.

• “The possibility remains that the kind, rather than the amount of fat in the diet is responsible for atherosclerosis.”

Ancel Keys was alert to the idea that sugar might be an alternative dietary explanation to his own as a cause of heart disease. From the late 1950s to the early 1970s, he held an ongoing debate in the scientific literature with John Yudkin, a professor of physiology at Queen Elizabeth College, London University, who at the time was the man behind the sugar hypothesis. "Keys was very opposed to the sugar idea," Daan Kromhout recalled in an interview, though he could not say why. Philosophers of science would say that the job of a scientist is to be as skeptical as possible about his or her own ideas, but Keys was evidently just the opposite. "He was so convinced that fatty acids were the thing in relation ot atheroschlerosis, he saw everything from that perspective," says Kromhout. "He was a very driven person and had his own point of view." About the views of others, Keys could be aggressively disaparing: Yudkin's idea that sugar causes heart disease is a "mountain of nonsense," he concluded at the end of a nine-page criticque in Artherosclerosis. "Yudkin and his commercial backers were not deterred by the facts; they continue to sing the same discredited tune," he wrote later.

Keys specifically defended his Seven Countries study from the idea that sugar might explain some of the mortality differences he observed. 

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Nina Teicholz - TBFS - page 42