CrossFit | Keys' Scientific Abandon

Keys' Scientific Abandon

ByCrossFitDecember 31, 2018

Ancel Keys launched his landmark Seven Countries Study (1) in 1958, pioneering both the use of huge population studies to establish relationships between food and health and an influential understanding of the nature of a healthy diet that has been with us ever since. The Seven Countries Study was essential in forming the belief that consuming saturated fat increases blood cholesterol, leading in turn to atherosclerosis and heart disease. It was one of the largest and most ambitious scientific projects undertaken at the time, and Keys quickly became a well-known public authority on heart disease.

Certain critical issues, however, have always undermined the study’s core conclusions. They are manifest in Keys’ thinking and have been institutionalized in nutritional epidemiology research ever since. To understand these issues, it helps to look at Keys’ earliest work on this “diet-heart hypothesis” and how it evolved.

Keys formulated his diet-heart hypothesis based on research he carried out personally in Greece, Italy, Spain, South Africa, Japan, and Finland. This led to a 1953 publication laying out his thinking and supporting his conclusions with what he would later call a “remarkable relationship” between fat consumption and heart-disease fatality visible even in easily available national statistics. While Keys’ 1953 argument and the supporting evidence were simplistic, the problems with its logic are still characteristic of much of nutrition science today.

Two graphs: One showing the 6 countries Keys surveyed in 1953, the other showing 22 countries and a weaker correlation between heart deaths and calories from fat.

Figure 1: Graphing of all 22 countries shows a weaker correlation than what Keys presented. (CrossFit Inc.)

In his 1953 article Atherosclerosis: A Problem in Newer Public Health,” Keys published a graph (Figure 2 below) linking fat-calorie availability in 1949 in six countries to deaths from coronary heart disease in middle-aged men. The graph seemed to demonstrate a striking, near-perfect correlation between fat intake and degenerative-heart-disease mortality, ranging from fewer than 1 in 1,000 deaths in the under-10-percent-fat-eating Japanese to over 7 in 1,000 deaths from the nearly 40 percent fat diets of Americans, with Italy, England and Wales, Australia, and Canada falling neatly along the curve between them (2).

A graph showing mortality from degenerative heart disease in men from 1948-1949.

Figure 2: Keys’ 1953 graph, presented as follows: “Mortality from degenerative heart disease (categories 93 and 94 in the Revision of 1938, categories 420 and 422 in the Revision of 1948, International List. National vital statistics from official sources. Fat calories as percentage of total calories calculated from national food balance data for 1949 supplied by the Nutrition Division, Food and Agriculture Organization of the United Nations).”

The graph caused an international stir, thrusting Keys’ favored diet-heart hypothesis—that dietary fat increases cholesterol in the blood and elevated cholesterol causes heart disease, hence dietary fat causes heart disease—to the fore and launching its trajectory from hypothesis to “proven” fact, where it has persisted for half a century.

In “Fat in the Diet and Mortality From Heart Disease; A Methodologic Note,” Jacob Yerushalmy and Herman E. Hilleboe, both experienced statisticians in the public-health world, exposed the problems with Keys’ methodology and statistical analysis as well as his conclusion that the data supported a causative role for fat as the driver in the development of degenerative heart disease (3).

Based on the data expressed in the graph in his 1953 paper, Keys had speculated that “dietary fat somehow is associated with cardiac disease mortality at least in middle age.” By the time he got to the Conclusions section in the same paper, his speculation had strengthened to this: “The different age-specific death rates of men 40 to 65 from degenerative heart disease in different countries are directly related to the differences in those countries in the proportion of the total calories derived from total fats.”

While this bolder statement could be drawn from the data Keys presented for the six countries he selected for his graph, there were several methodological and analytical flaws, as Yerushalmy and Hilleboe pointed out in their 1957 rebuttal (and in a separate 1957 paper published by Hilleboe), beginning with the selection bias inherent in the data. This was the problem with Keys’ basing his selection on his exploratory research—the scientific equivalent of stacking the deck in a game of cards:

“In studies of association, as in any other study, the method of selecting data largely determines whether the results can safely be generalized. … Hence, it is of first importance to know on what basis the six countries were selected, in order to determine whether the findings for them can be generalized to other countries. Since no information is given by Keys on how or why the six countries were selected for (his graph), it is necessary to investigate the association between dietary fat and heart disease mortality in all countries for which information is available.”

If data of 12 countries had been included in the graphs, as shown below in Hilleboe’s figure, the case for an association (let alone a causative relationship) between dietary fat consumption and death from degenerative heart disease becomes less compelling (4).

A collection of scatter diagrams of 12 countries according to percent of calories derived from fat and mortality from heart disease for males by age.

Figure 3: Hilleboe’s graphs, presented as follows: “Scatter diagrams of 12 countries according to percent of calories derived from fat and mortality from heart disease for males, by age.”

Yerushalmy and Hilleboe further noted that relevant information was available for 22 countries at that time and went on to describe the dangers of selective parsing of the data, such as the method employed by Keys:

“As an illustration of the importance of this question of selection, it may be of interest to show how by selection of countries it is possible to ‘demonstrate’ an apparent inverse relationship between percent of calories from fat and mortality from vascular lesions affecting the central nervous system (i.e., stroke).” 

They used Figure 4 below to illustrate the point.

A graph showing mortality from vascular lesions affecting the central nervous system (B-22) and fat calories as percent of total calories in males 55-59 from 6 countries.

Figure 4: Yerushalmy and Hilleboe’s graph, presented as follows: “Mortality from vascular lesions affecting the central nervous system (B-22) and fat calories as per cent of total calories in males fifty-five to fifty-nine years from six countries selected for this specific purpose. Calculated from national food balance data by F.A.O. (Food and Agriculture Organization of the United Nations).”

It is almost inconceivable that the Seven Countries Study was performed with such scientific abandon.

Keys’ interpretation of this data and failure to understand basic principles of scientific methodology were then manifest in the subsequent Seven Countries Study, in which he once again selected his countries and the sites of study knowing in advance what he was likely to find (5). That more famous work would be criticized by many, including Russell Smith, Ph.D. A psychologist with a strong background in mathematics and physiology, Smith concluded:

“The word ‘landmark’ has often been used to describe Ancel Keys’ Seven Countries Study, commonly cited as proof that the American diet is atherogenic. The dietary assessment methodology was highly inconsistent across cohorts and thoroughly suspect. In addition, careful examination of the death rates and associations between diet and death rates reveal a massive set of inconsistencies and contradictions. . . . It is almost inconceivable that the Seven Countries Study was performed with such scientific abandon.” (6)

Whether or not there truly was, or is, a correlation between fat intake and heart disease in the countries Keys surveyed, the data was insufficient to clearly show fat intake was the primary factor affecting heart-disease risk. Unfortunately, these biased data and the ways they were interpreted by Keys and others helped cement the belief that dietary fat causes heart attacks, and so the diet-heart hypothesis.


1. Keys A. Coronary heart disease in seven countries. Circulation 41(1): 186-195, 1970.

Keys and his team published the results of the Seven Countries Study across a number of publications, including multiple book-length summaries. A full list of publications can be found here

2. Keys A. Atherosclerosis: a problem in newer public health. Journal of the Mount Sinai Hospital, New York 20(2): 118-139, 1953. Available here.

Keys’ review of the clinical significance of atherosclerosis and the significance of cholesterol in heart-disease risk (and of diet to blood cholesterol levels). Keys begins by noting high levels of heart-disease mortality are not inevitable given significantly lower rates observed in other nations (citing Italy as a specifically significant example). He also notes that heart-attack patients tend to have higher total cholesterol levels (as do diabetics) than the general population, concluding “measurement of cholesterol and allied substances in the blood serum affords an indication of the tendency towards the development of atherosclerosis and degenerative heart disease.” Regarding the effect of diet on heart disease, he cites observations of a significant decrease in serum cholesterol on “a modified rice-fruit diet” containing “no cholesterol and extremely little fat,” as well as, more famously, a graph showing a positive relationship between fat intake (as a percentage of total calories) and heart-disease mortality across six countries (Japan, Italy, England/Wales, Australia, Canada and the U.S.). Keys notes: “All the data summarized here suggest an important chain of relations between the total fat content of the diet (or the proportion of fat calories of the total metabolized), the cholesterol (and lipoprotein) concentration in the blood, the development of atherosclerosis, and the mortality from degenerative heart disease. … It must be concluded that dietary fat is somehow associated with cardiac disease mortality, at least in middle age.” He suggests the high levels of fat intake in the U.S. may be related to the high levels of cardiovascular mortality seen in the same.

3. Yerushalmy J and Hilleboe HE. Fat in the diet and mortality from heart disease; a methodologic note. New York State Journal of Medicine 57(14): 2,343-2,354, 1957. Available here.

Yerushalmy and Hilleboe drew on data from the Food and Agriculture Organization of the United Nations (FAO) to reassess Keys’ famous 1953 conclusion that share of calories from fat and coronary mortality rates were strongly correlated. Analyzing data from 22 countries, they found a weaker (but still significant) correlation between dietary fat consumption and heart disease than Keys. They also found animal protein correlated more strongly with coronary heart-disease mortality than proportion of calories from fat. Perhaps most importantly, they noted fat intake may correlate with heart-disease mortality as a proxy of a country’s development, and so not be the driver of heart disease. Note, however, that by the time this study emerged, Keys had already begun preparations for the Seven Countries Study, and so this analysis may have had a limited impact on it.

4. Hilleboe HE. Some epidemiologic aspects of coronary artery disease. Journal of Chronic Diseases 6(3): 210-228, 1957.

Hilleboe reviews different factors correlating with heart disease, concluding an association exists between calorie and/or fat intake and heart disease, but that the existing information can “be used to form hypotheses for field testing.” Further: “It is apparent from these scatter diagrams that there is no sound basis for the statement that a strong parallelism in the different countries exists between fat consumption and heart disease mortality. In countries where the calories derived from fat were between 30 and 40 per cent, there were extreme variations in the cardiac death rates, in each of the seven age groups shown.”

5. Countries and cohorts. (n.d.). Available here

6.  Smith RL and Pinckney ER. Diet, Blood Cholesterol, and Coronary Heart Disease: A Critical Review of the Literature (Vol. 2). Sherman Oaks, California: Vector Enterprises, 1991. Available here.

All links accessed Dec. 31, 2018.

Comments on Keys' Scientific Abandon


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Matthieu Dubreucq
October 18th, 2019 at 9:51 pm
Commented on: Keys' Scientific Abandon

Great simple summary of the issues with Keys' studies. This should be a must read for any nutritionist, physician and trainer. Thank you.

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Malcolm Kendrick
January 15th, 2019 at 3:59 am
Commented on: Keys' Scientific Abandon

Perhaps Keys greatest fraud was that he was a lead investigator of the Minnesota Coronary Experiment (MCE) which found that replacing saturated fat with Omega-6 fatty acids did reduce cholesterol. However, the more that the cholesterol fell, the greater the morality rate.

This trial ran from 1968 - 73.

It was not published at the time... because?

The data was discovered, analysed, and published in the BMJ in 2016.

The only conclusion that can be drawn about this dismal scientific episode is that Keys buried the results because they absolutely contradicted the diet-heart hypothesis and demonstrated that vegetable fatty acids (at least Omega-6 fatty acids) are damaging to human health.

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richard morris
January 7th, 2019 at 9:46 am
Commented on: Keys' Scientific Abandon

This is a good exposition on Ancel Keys' observational "Seven countries" study as a basis for his diet heart hypothesis - that Fat and in particular Saturated fat is causal for Cardiovascular disease. What it misses is that Keys also determined to test his hypothesis in the Minnesota coronary experiment.

The MCE was a double blinded controlled clinical trial in 6 Minnesota mental hospitals. Replacing butter with corn oil lowered cholesterol as predicted and raised incidence of CVD. And then the results were buried because they were “disappointing”.

Ancel Keys knew in 1989 that he was not only not correct, he was also precisely wrong.

The National Heart, Lung and Blood Institute funded that study. It's worth speculating how much expensive bad advice they continued to give in the 27 years from the study's conclusion in 1989, until the exposition of the study's actual results by Chris Ramsden in 2016

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Dale Saran
January 8th, 2019 at 6:40 pm

Yet another "co-inky-dink" that forces me to conclude "malice" on the part of Mr. Keys, though I suppose that hardly matters in the long run.

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Katina Thornton
January 5th, 2019 at 10:51 pm
Commented on: Keys' Scientific Abandon

At the Symposium on Atherosclerosis in March of 1955, Keys presented his paper entitled "The Relationship of the Diet to the Development of Atherosclerosis in Man." Two conclusions that deserved more attention from the scientific and medical community were:

1." ...there is no evidence that dietary cholesterol, other things being equal, has any influence on atherosclerosis in man."

2. "The effects of different food fats in man have been inadequately studied."

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Peter Shaw
January 18th, 2019 at 10:45 pm

It’s interesting to me how this stuff gets overlooked...

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Erin Westmoreland
January 5th, 2019 at 10:32 pm
Commented on: Keys' Scientific Abandon

“Whether or not there truly was, or is, a correlation between fat intake and heart disease in the countries Keys surveyed, the data was insufficient to clearly show fat intake was the primary factor affecting heart-disease risk. Unfortunately, these biased data and the ways they were interpreted by Keys and others helped cement the belief that dietary fat causes heart attacks, and so the diet-heart hypothesis.” — YES!!!!! Loved this section of your review, well said.

I felt like the majority of this review was based on the fact that Keys cherry picked 6 countries to include in his iconic graph versus all 22 that were researched in the study. While a less compelling correlation, there is still a correlation between fat intake and heart deaths with all 22 countries considered. I think the even more viable argument here has to do with how our food system has changed because of Keys’ work. I think one of the most harmful things that has come from Keys’ studies was what the food industry/large health organizations did with this information and how they utilized it to sell more processed foods. In 1961, Ancel Keys landed a position on the nutrition committee for the American Heart Association. That same year, the AHA advised Americans to replace the saturated fats in their diets with polyunsaturated fats. This prompted Americans to start utilizing PUFAs found in highly processed hydrogenated oils (i.e. corn, canola, soybean, etc.) instead of animal fats such as butter. Around the same time that Keys made his argument against saturated fat, British physiologist, John Yudkin argued that sugar is more closely related to coronary heart disease incidence and mortality. Both Keys and Yudkin could find some support in their theory, but this could be because people eat foods, not isolated constituents of food (Dinicolantonio, Lucan, O’Keefe 2016). Slightly off topic but it’s also interesting to note that the first statin hit the market in 1987–likely insinuating that Keys’ recommendations for reducing cholesterol may have worked out differently than planned.

[I’d be curious to plot the timeline of sales for “low-fat” items and PUFAs to the release of Keys’ studies and his time on the AHA board.]

The study by Yerushalmy and Hilleboe is referenced often in response to Keys’ study, however, Yerushalmy and Hilleboe did find that animal protein correlated with coronary heart-disease mortality. Crossfit is known to promote a “paleo” style diet which can be meat heavy (especially in the eyes of the public). Not a bad thing, I just think it’s a slightly missed opportunity to draw on that fact that the paleo diet can be veg heavy with high-quality meats acting more like a side dish than a center of the plate item.

Maybe what Ancel Key’s was missing was less about the lack of correlation and more about what other aspects of the participants diet could have been influencing their rate of mortality. What types of saturated fats were they eating? Were their diets full of processed foods? How much added sugar were they consuming? What happens when saturated fats are replaced with refined carbohydrates and added sugars?

In some ways, I do consider Keys’ work somewhat ‘landmark’–albeit, maybe not in the most positive light. However, it was one of the first studies to show us a correlation between diet and overall health/mortality. It is my assumption that this sparked Americans to actually consider their food choices in relation to their health. I’m looking forward to seeing more from CrossfitHealth!

Dinicolantonio, J. J., Lucan, S. C., & O’Keefe, J. H. (2016). The Evidence for Saturated Fat and for Sugar Related to Coronary Heart Disease. Progress in Cardiovascular Diseases,58(5), 464-472. doi:10.1016/j.pcad.2015.11.006

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Jessica White
January 3rd, 2019 at 2:30 pm
Commented on: Keys' Scientific Abandon

According to Merriam-Webster science is ”The state of knowing: knowledge as distinguished from ignorance or misunderstanding.”

Also “A system or method reconciling practical ends with scientific laws.”

Regardless of how you choose to define science, it’s arguably NOT a static concept. We don’t say, “yeah that was science, we did that science thing once, let’s move on.” Science is never done. Knowledge evolves.

So in his case, what the hell happened to the rest of the scientific method, those important principles just beyond generating a hypothesis and testing it? I think it’s important to say that again: testing it. We (should) know that can mean the results require you to refine your hypothesis or worse yet, set your ego aside for a moment, to perhaps reject it and start over.

I don’t think anywhere it says the converse: refine or reject the data to fit your hypothesis. This sounds laughable but exactly this has been going on with selectively publishing studies that support the hypothesis.

What we have to remain aware that a cognitive assumption we make about an observation in the world influences our interpretation of the “data”. No big deal right, probably human nature, but that’s where the critical analysis part of the scientific method should really be used. Nowhere that I recall does the scientific method indicate the point at which you stop evaluating new knowledge and write your hypothesis into law.

So thank you CrossFit for picking up the misplaced principles of scientific methodology, to continue the search for truth.

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Andréa Topper
January 2nd, 2019 at 7:13 pm
Commented on: Keys' Scientific Abandon

The sugar industry funded Keys’ collegiate laboratory for decades. It's no wonder he conveniently omitted data that would have disapproved his theory that dietary fat caused heart disease and that sugar had no role in metabolic derangement. Then he made the cover of Time magazine in 1961, the same year the American Heart Association Report advised Americans to “reduce intake of total fat, saturated fat and cholesterol. Increase intake of polyunsaturated fat.”

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Andréa Topper
January 2nd, 2019 at 7:12 pm
Commented on: Keys' Scientific Abandon

The sugar industry funded Keys’ collegiate laboratory for decades. It's no wonder he conveniently omitted data that would have disapproved his theory that dietary fat caused heart disease and that sugar had no role in metabolic derangement.

Then he made the cover of Time magazine in 1961, the same year the American Heart Association Report advised Americans to “reduce intake of total fat, saturated fat and cholesterol. Increase intake of polyunsaturated fat.”

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Michael Emery
January 2nd, 2019 at 5:54 pm
Commented on: Keys' Scientific Abandon

As a cardiologist, I find the discussion on nutrition with patients increasingly difficult. The "textbook" teaching and continued publications from major societies about dietary fat and heart disease continues to be problematic. Several recent reviews (with several co-authors who promote vegan lifestyle) continue to found their recommendations on these same poorly constructed theories:

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Tim Coleman
January 3rd, 2019 at 12:19 am

This is the beauty of having Registered Dietitians to provide evidence-based dietary education.

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Mike Warkentin
January 2nd, 2019 at 3:42 pm
Commented on: Keys' Scientific Abandon

Dr. Eades' mention of Keys' "cudgel" is apt. Despite the fact that Keys' science was flawed, he had no qualms about attacking others with aggression. It's somewhat entertaining to see that he even tried to rely on criticisms of methodology and evidence when his own work was so poor.

In the Journal article "Devil in the Diet" by Andrí©a Maria Cecil, she presented this Keys quote from the 1971 paper "Sucrose in the Diet and Coronary Heart Disease":

“It is clear that Yudkin has no theoretical basis or experimental evidence to support his claim for a major influence of dietary sucrose in the etiology of (coronary heart disease); his claim that men who have CHD are excessive sugar eaters is nowhere confirmed but is disproved by many studies superior in methodology and/or magnitude to his own; and his ‘evidence’ from population statistics and time trends will not bear up under the most elementary critical examination. But the propaganda keeps on reverberating.”

In light of the basic but disastrous flaws in the Seven Countries Study, Keys was bold to sarcastically punctuate the word "evidence" when related to Yudkin's work.

For more on Yudkin, Keys and the consequences of the diet-heart hypothesis, read Cecil's article here:

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Doug Dengerink
January 2nd, 2019 at 2:24 am
Commented on: Keys' Scientific Abandon

Let us press on and show the truth to the people. Let us also not reproduce their folly in our fervor.....

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Clarke Read
January 1st, 2019 at 9:54 pm
Commented on: Keys' Scientific Abandon

A lot of accusations have been leveled at Keys and SCS, some of them justified, some unjustified. To follow the point Eades makes above, a lot of the issues with both his 1953 analysis and with Seven Countries (SCS) are secondary to the issues in their interpretation. Putting accusations of cherry-picking (both within the sampled population and the presented outcomes) aside, Keys DID show a correlation between fat consumption (or saturated fat consumption in SCS) and heart disease mortality, and while there may have been other evidence to put this correlation on shakier ground at the time, it was not entirely without merit. The larger problems stemmed from the conviction with which these results were pushed into the public health space.

At best, SCS (and Keys’ observations prior to SCS) were observational, and so it was impossible to show any element of the diet CAUSED heart disease (incidence or mortality) based on that data. At worst, they were observational data that attempted to identify a single causal variable by comparing populations that differed in many ways. As many others have discussed, fat intake during this period was a proxy for a country’s level of economic development (which contains a mess of other confounders), and yet the fact that fat intake may have simply been tracking a lurking variable quickly disappeared as Keys and others began using observational (and later, weak trial) data to point the finger at fat specifically. Both scientists and public health officials made the jump from the HYPOTHESIS that fat (or saturated fat) caused heart disease to the CONCLUSION that fat/SFA caused heart disease. This jump unfortunately pushed resources toward this unproven hypothesis and simultaneously crowded out other hypotheses that may have, at the time, been supported by equally strong evidence.

If any damning accusation can be leveled at Keys and his colleagues, it may be this - that whatever Keys wrote in his papers (which, as Taubes noted above, often respected the limits of observational research), the shift in the way Americans thought about heart disease after Keys’s work reflects suggestive evidence being treated as conclusive.

We need not assume Keys was malicious, incompetent or self-serving to see his work had a degree of influence on subsequent scientific thinking and policy beyond what a strict interpretation of the data would support.

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Stanley Nasraway
January 2nd, 2019 at 12:19 pm

I was thinking the same thing yesterday. Keys may not have been intentionally malicious, but was duped by standards of the 1950s. I can tell you that research methodology and interpretation in Medicine is far better in 2019 than it was in 1989, for example. Sample sizes are much larger, and reliance on PRCTs is much greater. Also, the shift toward low fat (therefore, high CHO diets) was probably an unintended consequence of the conclusions drawn by Keys and others at the time. They surely did not predict the disproportionate shift toward high CHO.

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Benjamin Allen
January 1st, 2019 at 9:38 pm
Commented on: Keys' Scientific Abandon

This 1958 study depicts CrossFit Health's fight against Big Soda well past the obvious macronutrient debate. In 1957 British scientist Dr. John Yudkin studied cardiac disease causation and concluded that sugar was the culprit. Science was not the metric for success here, but well funded campaigns to falsely brand your counterpart, and accuse them of the very malfeasance you are committing. As CrossFit continues to expose the Big Soda backing of our national research centers, national activity guidelines, and exercise is medicine prescriptions, we uncover the truth that Dr. Keys tried to destroy. Dr. Keys claimed that Dr. Yudkin was in bed with the meat and dairy industry, all the while the sugar industry has funded the direction of medical research in cardiac disease since President Eisenhower had his heart attack. Exposing the truth of bad science and filling the void with elegant solutions in nutrition and fitness is the heart of CrossFit, excited to see where 2019 takes us!

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Karen Thomson
January 3rd, 2019 at 12:29 am

Ben, right you are to emphasize the vitriol Keys had for Yudkin.

It seems that many efforts were made by Keys and other scientists to discredit Yudkin’s work, most of them successful. In his book ‘Pure, White and Deadly’ (1972) Yudkin argues there was a stronger relationship between the rise in heart disease and the rise in the consumption of sugar than that of fat which flew in the face of Keys’ hypothesis.

As Ian Leslie recounted in 2016, “Ancel Keys was intensely aware that Yudkin’s sugar hypothesis posed an alternative to his own. If Yudkin published a paper, Keys would excoriate it, and him. He called Yudkin’s theory “a mountain of nonsense”, and accused him of issuing “propaganda” for the meat and dairy industries. “Yudkin and his commercial backers are not deterred by the facts,” he said. “They continue to sing the same discredited tune.””

Julia Llewellyn Smith noted how, after Keys’ attacks, Yudkin found himself progressively marginalized - removed from speaking engagements, publications and research opportunities.

The propaganda against Yudkin was alarming, a smear campaign which was largely successful.

I recently read this statement made by Yudkin:

"Can you wonder that one sometimes becomes quite despondent about whether it is worthwhile trying to do scientific research in matters of health?" he wrote. "The results may be of great importance in helping people to avoid disease, but you then find they are being misled by propaganda designed to support commercial interests."

I find it alarming that throughout the history of medicine we find visionaries, with simple solutions, that were told they were wrong. These men (and women) were then driven mad by propaganda against then, having their careers and reputations ruined. Many of them died health heroes without knowing it or even being acknowledged.

It saddens me that Yudkin (whose work we are only really starting to appreciate now) died a forgotten man.

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Neil Kanterman
January 1st, 2019 at 8:47 pm
Commented on: Keys' Scientific Abandon

The damage done by this study and the near global acceptance of the lipid-heart hypothesis has caused death and disease on such a massive scale that it's difficult to truly comprehend.

I grew up with the food pyramid and it's 8-11 servings of grains suggested daily as the base. This recommendation alone is likely responsible for millions of people being sicker and dying, and an expenditure on health care which can probably be counted with 9 or 10 digits. While it's great to see a real shift begin in what seems to be a far better direction with understanding of what is at the core of metabolic syndrome and heart disease, the fact that there is no accountability for this fraud in abhorrent.

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Stanley Nasraway
January 1st, 2019 at 8:23 pm
Commented on: Keys' Scientific Abandon

Crossfit deserves credit for publishing this short analysis of how Ancel Keys went wrong, and it's instructive to hear from Mr. Taubes, with whom I agree. And Sean Rockett, that's why we did Journal Club in our Surgical ICU each Friday when you were an intern, and still do, to understand the Scientific Method and scientific principles. Most especially to understand that correlation is NOT causation. With Methodolgy in mind, I would strongly encourage CrossfitHealth and Crossfit leadership and members to adhere to the same principles. Which is why it's a disservice to patients to tout things like an unproven Ketogenic diet to cure or reverse cancer in the absence of Prospective Randomized Controlled Trials in humans with cancer, as just one example. I think Crossfit is an excellent fitness platform; now that it has ventured into Health, I look forward to it using the same high principles of interpretation of data and humble drawing of conclusions for which it criticizes others. Stanley Nasraway, MD, FCCM; CFL1, CF enthusiast, Professor of Surgery, Medicine, Anesthesiology & Perioperative Medicine. Tufts, Boston.

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Russ Greene
January 1st, 2019 at 8:56 pm

Dr. Nasraway, could you please cite and quote the CrossFit Health statement or claim about the ketogenic diet and cancer to which you object?

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Tim Coleman
January 3rd, 2019 at 12:17 am

Interpretation of research doesn’t come easy to many people. Those fortunate enough to have completed a masters level degree, especially in science have an excellent skillset for this. Those people should help to “read between the lines” for data manipulation, biased, etc.

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Shakha Gillin
January 1st, 2019 at 5:35 pm
Commented on: Keys' Scientific Abandon

Ancel Keys study exemplifies what is wrong in science and medicine, and why we are facing the greatest epidemic of chronic disease.

It is almost unimaginable that a study which deviated from any possible scientific method could become the basis by which we practice medicine. Keys cherry picked countries to support a preconceived hypothesis. This false claim become a “fact”, and this unsupported and biased “diet-heart” claim became the authority for nutrition and public health.

As a physician, I don’t remember ever being taught why we thought cholesterol was considered unhealthy, and why low-fat was beneficial for patients. I just remember being taught that. It was as if these recommendations were facts. While in reality they were false claims based on a bad study. (And the mishaps after). If I had been presented the graphs with the 22 countries, I seriously doubt I would have taken the recommendations as a fact. Instead, we are presented with what to tell patients, and reinforced this through training and then as national medical recommendations for the standard of care practice.

This is why we need to uncover these lies. So we can understand how we got to where we are (in a big mess), and what the truth really is.

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Scott L. Royal
January 1st, 2019 at 5:10 pm
Commented on: Keys' Scientific Abandon

What you need to know is that in Jon Barrons PDF — Lessons from the Miracle Doctors, on page 105 has the following information about an effective alternative to the horror show known as bypass surgery. “As it turns out, there is an alternative that’s so effective that in countries such as New Zealand, it’s against the law to perform a bypass unless this alternative has been tried first. This treatment is called chelation therapy, and it could save hundreds of thousands of lives a year.” He further states, “since chelation therapy would cost the medical establishment billions of dollars a year, it’s not surprising they don’t use it.” There are also books to be found out there “Bypassing Bypass Surgery” and others on chelation therapy.

Why do I know about this? In 1987 I buried my 48 year old mother. She had a triple bypass and another 8 or so surgeries after that, culminating in the loss of both her legs above the knees and a massive stroke that effectively rendered her brain dead. 2.5 months and they had extracted every nickle they could from her body and insurance. At 24 I signed the release to remove life support and 2 days later I closed mom’s eyes.

Modern medicine, with the full consent of our own government, has turned America into a medically enslaved nation.

The clock is ticking boy’s, your days in power are numbered.

Semper Fi

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Dale Saran
January 8th, 2019 at 6:23 pm

Very sorry for your loss, Scott. Semper Fidelis, Brother.

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Russ Greene
January 1st, 2019 at 4:49 pm
Commented on: Keys' Scientific Abandon

Something has gone terribly wrong. Among other disturbing trends, US life expectancy has declined three years in a row despite a period of economic expansion. To be sure, opioid addiction and suicides have played a role. Nonetheless the top causes of death remain diet-related illnesses such as heart disease and cancer. Some chronic conditions, such as Alzheimer’s, are increasing rapidly (even controlling for age). (see

In a time of plenty, why are most committing suicide, swiftly or slowly?

It’s not singly Republicans’ or Democrats’ fault. The decline began under Obama administration, during the first year of full implementation of the Affordable Care Act. It has continued under Trump and his typically, more uncouth embrace of food and beverage industry influence. Moreover, the same problems are happening throughout the developed world, so it is not just an American problem.

Let’s consult Genesis. In the Garden of Eden, a speaking serpent enticed Eve to eat fructose. The serpent promised Eve, contra God, “Ye shall not surely die.” Satan (embodied by the serpent), spoke a half-truth. Eve would not die immediately upon consuming the forbidden fruit, but it would condemn her and her husband to unnecessary misery, followed later by a preventable death. And so suffered humanity.

Some academics have interpreted this tale as an allegory for transition from Eden’s hunter-gatherer lifestyle to the toilsome, disease-ridden, and tyrannically taxed agricultural society Adam and Eve’s offspring experienced outside the gates. This transition brought a decline in health, and increase in disease - first infectious, caused by crowding, then chronic, caused by bad diet and sedentarism. (For more on this transition I recommend Against the Grain by Yale University’s James C. Scott.)

The logical response to modern (in the broad sense) epidemics would be to look for modern causes. Having discerned those causes, perhaps we would return to at least some pre-modern habits as well. Why did we humans, self-acknowledged as rational beings, not follow logic’s course? Today’s post suggests a culprit: nutritional “science” and its luminaries such as Dr. Keys. This field, by a and large, attributed our modern epidemics to ancestral dietary components, alternately total fat and saturated fat. And as we have seen above and in the comments, a full and proper analysis of the data does not appear to support the conclusions of Keys and Co.

Back to Eden. As in Genesis, let’s grant the (fructose-absolving) devil his due. Who speaks today for Keys?

David Katz, allegedly of Yale University, and Walter Willett, whom Harvard University more enthusiastically embraces co-authored with others via the “True Health Initiative.” They defend the Seven Countries Study in their white paper, “Ancel Keys and the Seven Countries Study: An Evidence-based Response to Revisionist Histories.” (I have addressed Dr. Katz’s numerous, oft-undisclosed conflicts of interest here:

Reading the white paper, we notice several points of divergence.

Did Keys propose total dietary fat, or saturated fat, as the primary independent variable responsible for heart disease? The CrossFit post focuses on the former, Katz and Willett’s white paper the latter. The white paper posits that in Keys’ study,

“Total dietary fat was not associated with coronary heart disease. For example, the Greek cohorts ate about 40% of their daily calories from fat and the Japanese ate only 10% while both cohorts had very low coronary disease rates. 3,4 SCS was the first systematic study to illustrate this important dichotomy, that low rates of coronary heart disease and, in fact, of total mortality can be found with low and high total fat intakes, depending on the nature/sources of the fat and the rest of the eating pattern.”

It appears that Keys initially considered dietary fat as the primary cause, and then later switched to saturated fat after further research. This retreat from dietary fat to saturated fat, culminating in the 2015 dietary guidelines’ erasure of an overall fat limit, is noteable by itself. Perhaps the troublesome case of dairy-sourced saturated fat will compel a further retreat.

Why did Keys only select these few countries to focus on when a wider data set would have likely have forced a more complex conclusion? Was it due to intentional bias, or practical constraints? The white paper claims Keys selected his countries “based on practicality and dietary variation.” Further, the paper defends Keys from “Allegations suggesting that SCS researchers chose locations where they already knew the outcomes.” Instead, these allegations of biased selection are “clearly false based on review of primary source material, the relevant timelines, and direct questioning of investigators.” Here the white paper assumes that Keys and co.’ statements can be taken on face value - that they truthfully understood and stated their own intentions, and that Keys’ knowledge of his prior results from 1953 did not unfairly influence the selection in his 1958 study. But perhaps it does not matter. Humans, even researchers, demonstrate ample capacity for self-deception. Even if Keys believed he selected his countries in good faith, that does not absolve him of the selection issues detailed above.

Gary wrote above that, “Had Keys chosen, for instance, France and Switzerland for two of his countries, instead of, say, Japan and Greece, he would have come up with an entirely different conclusion -- in this case, that consuming saturated fat is beneficial and heart healthy.”

In response to this idea, the white paper states,

“France was indeed invited to participate in the Seven Countries Study … Ultimately, representatives from France decided not to participate, possibly due to lack of desire, lack of funding, or both. There was no explicit intent on the part of the American SCS researchers to include or exclude France.”

Though again one must ask whether it matters if Keys deliberately excluded France and other similar apparently non-conforming countries, if their undisputed absence nonetheless produced pernicious effects.

A familiar refrain is that correlation does not equal causation. Even Keys understood this, as Dr. Eades’ citation proved. How, though, would it be possible to demonstrate causation in nutrition? And is this likely to occur given the constraints, ethical, financial, and practical, of the field? Chronic diseases by definition require years, decades, even full generations to fully manifest. Studying them from meal to grave, in adequately controlled experiments, has not been achieved. Controlling what humans actually eat ranges from extremely difficult in the short term to fully impossible in the long term. And even were we to conduct perfectly controlled, long-term studies, the Sugar Association and Coca-Cola’s International Life Sciences Institute would produce and cite their own studies as well, with varying conclusions. Meta-analysis would surely conclude the record to be mixed, the implications unclear. More research would certainly be needed.

Science is not going to save us from the serpent’s curse any time soon, I fear. Salvation must come from elsewhere.

To conclude, Katz and Willett’s white paper defending Keys nonetheless admits,

“high intake of refined carbohydrates is now considered to be a possible contributor to heart disease development; this was not evaluated.”


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Stanley Nasraway
January 2nd, 2019 at 12:23 pm

You asked me to "cite and quote the CrossFit Health statement or claim about the ketogenic diet and cancer". Crossfit Health sponsored Thomas Friedman at CFMD1, at the last Games' workshop on Health, and on this very site of the Journal. You didn't say it, but you sponsored it. I'm just asking you to better vet the science that you publish or reference. Today, people are criticizing Keys for his efforts 70 years ago. Yet even less science (no human) stands behind the statements in 2018 that you sponsored thru Friedman. JMHO.

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Russ Greene
January 2nd, 2019 at 12:28 pm

Thanks Stanley. I don't see anything from "Thomas Friedman" at CrossFit Health in a quick search. Did you mean Dr. Thomas Seyfried? If so, his mere presence and talk are not sufficient cause for objection, I don't think. To effectively evaluate your criticism, we need you to quote him at the point you believe he overstepped the available evidence. Thank you again.

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Ryan Castanhinha
January 1st, 2019 at 3:16 pm
Commented on: Keys' Scientific Abandon

If the situation is driven by money, us as crossfit coaches need to be doing are best to bring awareness and shed light to the community. Establisbing a proper nutrition system standard in crossfit that is clear for people to dive into that supports are science the way we do with are regular crossfit classes. I believe everyone as a coach and member needs more awareness and education to conquer our mission and ward off chronic disease.

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Paul Sexton
January 1st, 2019 at 2:24 pm
Commented on: Keys' Scientific Abandon

I feel like health is not the first priority in "healthcare". Granted I'm sure there are many individuals at every level across the broad spectrum of healthcare providers that it IS a priority. The industry as a whole, however, seems to be only concerned with profit. As it is currently structured, a healthy population is not profitable. The misinformation, falsified or exaggerated studies that have become the status quo, have achieved success due to whom those findings profit the most. It isn't the general populace. Those of us in this community are actively engaged in positive change and truth yet we face an immense battle. Thank you CrossFit for leading this charge.

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Dale Saran
January 8th, 2019 at 6:17 pm

Paul, that's likely because the term "healthcare" is nowadays used interchangeably with "health insurance" - two completely different products/services (and not accidentally, I should add). The (Un)Affordable Care Act was driven by certain insurers because it creates - FORCES - a market for their product by government fiat. Start with that understanding and what you see will start to make more sense.

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Sean Rockett
January 1st, 2019 at 7:07 am
Commented on: Keys' Scientific Abandon

Very upsetting to read but I am looking forward to a new generation of informed and educated physicians helping their patients in the future. One patient at a time. @Crossfithealth

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Pat Sherwood
January 1st, 2019 at 6:42 am
Commented on: Keys' Scientific Abandon

If the data does not support the predetermined conclusion that was obviously agreed upon well before the "study" took place then simply lie, twist, manipulate, and omit as necessary until you get the result you want......that is NOT science. Sadly, a large part of what the world has been lead to believe as "fact" or "truth" falls into this deceptive, misleading, and fraudulent category. It is time the real truth is told. I'm proud CrossFit will be leading the charge.

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Shakha Gillin
January 1st, 2019 at 9:47 pm


This sort of bad behavior would be expected at a primary school playground, but not in the sacred institution of science and medicine. It’s astonishing but real. Surprising, and yet not.

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MIchael Thalmann
January 3rd, 2019 at 2:32 pm

Pat, ancel keys is up there with Hitler and Mussolini in my opinion. He certainly caused more deaths, and definitely profited more... Seeing as how he wasn't executed or hunted, that is.

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Tyler Hass
January 1st, 2019 at 6:37 am
Commented on: Keys' Scientific Abandon

Ancel Keys’ diet-heart hypothesis is a flat earth approach to nutrition. Whatever feels right must be true. “Eating fat makes you fat” is intuitive. To disprove it requires a detailed scientific explanation of the hormonal mechanisms involved in nutrition. Meanwhile, the food industry is peddling low-fat muffins and other junk food with “Heart Healthy” stickers on the packaging. And to top it off, the food industry is actively funding science that perpetuates Keys’ fraudulent work.

It’s important to understand not just that Keys was wrong, but how and why. Too many people think science is just a collection of facts. Articles like this are a great lesson in scientific thinking. Great start to the new website!

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Glen Finkel
January 1st, 2019 at 5:51 am
Commented on: Keys' Scientific Abandon

Awesome to see a Global brand like CrossFit shine a spotlight on the gross misinformation that has been perpetuated by commercial interests for the last 50 years.

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Michael Eades
January 1st, 2019 at 4:16 am
Commented on: Keys' Scientific Abandon

The graph from Keys’ 1953 paper showing the tight correlation between deaths from heart disease and percent of calories from dietary fat is just that: A correlation. It’s axiomatic in the research world that correlation is not causation. It’s the mantra of any researcher worth his/her salt. It’s incredible to me that anyone with good sense took this graph seriously in the first place. After the cherry picking of countries had been exposed, it’s even more astonishing that anyone took Keys’ correlations as anything other than a joke. Yet this simple chart and the Seven Countries Study that followed are the basis for the lipid hypothesis — the idea that dietary fat causes an increase in cholesterol, which, in turn, increases the risk for heart disease — that has altered the diets of Americans (and others the world over) leading to the rise of obesity and type 2 diabetes to epidemic proportions. And that’s not to mention the trillion dollar’s worth of statins and other lipid-lowering drugs that have been sold worldwide.

All based on correlations from observational studies, which are worthless to prove causality.

Keys used his famous chart and his Seven Countries study to cudgel anyone who had the temerity to disagree with him into submission, even though his famous chart and famous study were worthless in terms of proving anything. No one knew this any better than Ancel Key’s himself, as is evident from these paragraphs he wrote at the end of Epidemiologic Aspects of Coronary Artery Disease, a paper he published in 1957:

“Epidemiologic investigations promise to make major contributions to the discovery and application of effective control and preventative measures against coronary heart disease. Though even properly conducted epidemiologic studies have limitations, they offer several kinds of utility. It is foolish to ask epidemiology for basic information on the mechanism whereby an environmental factor produces or influences the development of a disease, but it can provide clues for research by other methods, and it provides a device for testing hypotheses, not as to truth or falsity, but merely as to consistency with the distribution of the disease in question.

“When the frequency of a disease and some environmental factor tend to vary in the same direction, this is a clue to be followed up by similar epidemiologic methods applied in a wider variety of circumstances and by such experiments as may be feasible. On the other hand, a hypothesis about a relationship between any two or more variables that may be represented in populations, including a disease or a factor known to have some basic relationship to it, may be tested by comparisons within and between populations. This is not a test to prove causality which is seldom accessible to critical test by epidemiology but simply a way to decide whether the hypothesis is consistent with the distribution of the disease.”

If you read what he writes, Keys obviously understands the limitations of epidemiological studies. Buried amongst the obfuscation above lurks the truth.

“It is foolish to ask epidemiology for basic information on the mechanism whereby an environmental factor produces or influences the development of a disease…”

“…it provides a device for testing hypotheses, not as to truth or falsity…”

“This is not a test to prove causality which is seldom accessible to critical test by epidemiology…”

Clearly Keys knows these kinds of studies don’t prove causality or much of anything else for that matter. Yet he spent the bulk of his career performing such studies, using their data to vigorously promote the low-fat diet and the lipid hypothesis, and savagely attacking anyone who had the temerity to disagree with him.

It was joke science, but unfortunately the joke was on the millions of people who have become obese, diabetic, and spent money unnecessarily for a panoply of medicines, most of which are worthless in terms of prolonging life.

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richard morris
January 7th, 2019 at 10:09 am

... and when he did do a double blinded controlled clinical trial (Minnesota coronary experiment) to test the hypothesis he had generated from his observational study - the results were "disappointing" so he buried it.

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Nima Alinejad
January 1st, 2019 at 3:42 am
Commented on: Keys' Scientific Abandon

So much of modern medicine doctrine is built on the false altar of Ancel Keys. The damage done is incalculable.

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Brian Mulvaney
January 1st, 2019 at 10:10 pm

As long as there have been mariners and lights to guide them there have been tales, probably mythical, of "false lights" that draw the unwary onto the rocks where ship, cargo and passengers can be plundered. The false light of Keys is very real, and, yes, the loss is beyond measure.

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Gary Taubes
January 1st, 2019 at 3:27 am
Commented on: Keys' Scientific Abandon

As this post discusses, Ancel Keys's famous (or infamous, depending on perspective) Seven Countries Study was a landmark study because nobody had ever done such a huge, multi-country study before. But it was also landmark in that it pioneered the practice, standard operating procedure still today, of overinterpreting associations as evidence of causal relationships. And Keys had helped pioneer this technique a decade earlier when he published his analysis of fat consumption and mortality in six countries. In both cases, he stacked the deck by choosing his countries in advance in such a way that he predetermined what he would find.

There's a reason why researchers randomize study subjects, or select them at random, even when the subjects are entire nations or populations within those nations. It serves the purpose that shuffling cards does in a poker game and prevents precisely this type of deck stacking. (I spent much of last Saturday evening watching the 13-year-old whiz kid son of a friend doing some pretty damn impressive card tricks. You can make almost anything seem believable if you know where the cards are in advance, and never lose track of what you wanted to demonstrate before you started.) Had Keys chosen, for instance, France and Switzerland for two of his countries, instead of, say, Japan and Greece, he would have come up with an entirely different conclusion -- in this case, that consuming saturated fat is beneficial and heart healthy. There would have been no French paradox and perhaps we would not have had to live with the tragically misguided diet-heart hypothesis that these "landmark" studies and Keys's hypothesis helped advance and the low-fat-is-a-healthy-diet dogma that resulted.

Yerushalmy and Hilleboe were the first to point out precisely this problem in Keys early paper followed memorably by the British nutritionist John Yudkin. By the time the first results from the Seven Countries Study had been published in 1970, it was left to Russel Smith (and his colleague Ed Pinckney) to critically and methodically examine the evidence in support of the diet-heart hypothesis and the low-fat dogma that was already beginning to take over the country. I used Smith and Pinckney's report when I was researching Good Calories, Bad Calories 20 years later, and went through much the same learning curve. By that I mean, I had begun investigating public health in the early 1990s because physicists I had worked with on my previous books urged me to get involved. They had the occasion to review the epidemiologic data in support of the idea that electromagnetic fields from power lines caused cancer and had been stunned -- dumfounded, as Smith might have said -- by the lack of rigor and the dismal understanding of science and basic statistical logic demonstrated by the researchers themselves. In particular, that epidemiologists would make biased observations, cherry pick the data to fit their preconceptions and then present the associations observed as implying a causal relationship when no such causality could be inferred. My first articles on public health issues (in The Atlantic and then the journal Science) delved into precisely these issues. I had spent the better part of a decade learning about the level of rigor and skepticism needed to establish reliable knowledge (to "not fool yourself and you're the easiest person to fool," as the Nobel Laureate Richard Feynman put it), and this was considered a luxury by epidemiologists -- too hard to do -- and so unnecessary. Ancel Keys was the master of this "surely we must be right, so let's not question it" approach to science, and much of the discipline still thinks and works this way.

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Julian Festor
January 1st, 2019 at 5:37 pm

Thanks for taking the time to comment Gary

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MIchael Thalmann
January 3rd, 2019 at 2:32 pm

Gary, your research changed my life. Thank you.

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Ron Torrance II
January 3rd, 2019 at 4:04 pm

Thanks for all the diligent work Gary!! #truth #realfood

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