Today, official dietary guidlines around the world tell us to limit our consumption of fat, particularly saturated fat. This message has become so ingrained in all of our minds, that it is now just habbit to reach for low-fat milk or try to cut fat off your steak.

Yet, recommendations to reduce your intake of saturated fat based on flawed science. It is time to learn the shocking truth behind our fear of saturated fat so we can start making informed choices. In this article we will look at the history and politics that shaped the recommendations to avoid saturated fats in the USA. It was these American recommendations which ultimately led countries like Australia and the UK to follow advice to use vegetable oils and other low-fat products in place of naturally occuring, nutrient rich saturated fats.

Where did the global fear of saturated fat come from? 

America’s scientists, policy makers and huge food corporations have significantly influenced eating habits in the UK, Australia and indeed around the world, so to fully understand the origins of our fear of saturated fat we need to go back to post-WWII in the USA.

In post-WWII America traditional foods such as butter and lard were starting to be replaced by vegetable oils served as margarine. Margarine was produced by a process that was developed in the early 20th century called hydrogenation, which adds hydrogen to liquid oils (such as vegetable oils) to make them solid. The process of converting previously liquid vegetable oils into hard fat, which resembled butter was first developed by a German chemist in 1908 and was patented Proctor & Gamble, which originally used the technique to make soap. (1) Margarines and vegetable oils were a waste by-product of other industrial manufacturing processes and as such were far cheaper than traditional fats, which involved raising and killing animals, to produce.

Big food corporations recognised that they could create a whole new category of foodstuff, provided they could get consumers to choose margarine over butter. In 1911, P&G released a new non-animal, hard fat that was made entirely from vegetable shortening. Its was called “Crisco” which reflected the main ingredient – crystalised cottonseed oil. (2) The sucess of this animal fat replacements was rapid and as Nina Teicholz explains in The Big Fat Surprise, “Crisco sales multiplied forty times in merely fours years following its introduction…”, other similar products were quick to follow. Even before scientists went to work demonising saturated fat, Americans were starting to use margarine in place of butter. According to the Weston A Price Foundation between 1920 and 1960, butter consumption fell from about 18 pounds per person per year to 4 pounds.   

Something else also also occured during this twenty year period that caught scientists and politicians attention: there was a rampant increase in instances of cardiovascular disease (such as heart attacks) amongst Americans, particularly middle aged men. As the graph below illustrates consumption of margarine was also steadily rising.

This graph was taken from Butter Consumption Reaches a 40-Year High by Dr Mercola. (2)

Rather than health experts and policy makers identifying a link between the increase in vegetable oil consumption and heart disease they embarked upon a quest to find another culprit. So follows the development of the fear of saturated fat.

The lipid hypothesis: the fear of saturated fat starts with cholesterol 

In the early 20th century a German pathologist, Rudolph Virchow, theorised that cholesterol contributed to the build up of arterial plaques in one’s arteries. (3To further solidify this concept (no pun intended) in 1954, a Russian researcher, David Kritchevsky, published a paper describing the impacts of feeding cholesterol to animals. When added to the diet cholesterol formed plaques that clogged arteries and contributed to heart disease. (4) For those in America who had been trying to find the cause of the increase in heart disease since the war this raised concern about the American/ Western diet, which was rich in eggs, butter, meat, cream and cheese.

One minor detail that is still overlooked when the concept of cholesterol build up causing heart disease is cited today is that these trials were done on rabbits. Not humans, rabbits. Vegetarian rabbits with completely different digestive systems to humans and no naturally occurring cholesterol in their diets. As with much of the science that set the tone in later research around saturated fat and cholesterol inconvenient facts such as the whole rabbit thing were ignored.

David Kritchevsky also highlighted that polyunsaturated fats, predominantly found in liquid fats such as sunflower oil could lower cholesterol in rabbits. And so was born the lipid hypothesis:

“High cholesterol in the blood causes heart disease.”

This message was the golden ticket that industry was looking for to start touting vegetable oils and margarine as healthy. However, while the lipid hypothesis had set train in motion, there was no official proof that dietary cholesterol caused heart disease in humans. We will look more at cholesterol in a later article. The murmerings against the impacts of cholesterol were there, but now someone just needed to find out exactly what was responsible for rapidly growing rates of heart disease amongst Americans. Along came a man by the name of Dr Ancel Keys who would play a pivotal role in developing contemporary nutrition advice underpinned by a fear of saturated fat.

The diet-heart hypothesis 

During WWII Dr Ancel Keys had researched ways to treat widespread starvation, which exposed him to vast amounts of population and food data from America and Europe. It was around this time that heart disease was becoming a huge issue in the United States.

Keys had a strong interest in cardiovascular disease (CVD) or heart disease, which had occurred in many people that suffered starvation during the war. However, he noticed that in America it wasn’t actually those that were seriously malnourished who had heart disease, but the wealthier business executives who were amongst the best fed in the world. Conversely heart disease had decreased in Europe where food supplies were low. Something else that sparked Keys’ attention was that in Naples Italy, where people consumed a Mediterranean diet low in saturated fats and rich in olive oils and vegetables, heart disease was particularly rare – (although a closer look at the term “Mediterranean diet” reveals that diets in this huge region vary and saturated fat and red meat consumption is actually high in many parts).

At the time Southern Italy, where Keys had a personal affinity and enjoyed holidays, had a big population of people that lived to be over 100. So Keys hypothesised that there was a correlation between the amount of fat that a population consumed and their rates of CVD. His theory went that cholesterol, which is heavily present in saturated fats, could build up in the arteries and lead to blockages (atherosclerosis), resulting in a heart attack or stroke.

Keys began to share his ideas in various medical journals and publications. One notable and arguably ethically questionable experiment was conducted on schizophrenic patients in a hospital in Minnesota in 1957-8. He found that serum cholesterol went up after the men ate saturated fat and down when they consumed vegetable oils. This allowed Keys to further hone his theory about heart disease, now specifiying that it was saturated fat in particular that increased cardiovascular risk.

Keys developed the now infamous diet-heart hypothesis:

“A diet high in saturated fat increases cholesterol in the blood, which increases your chance of heart disease.”

Keys ideas became the subject of national attention in 1955, when President Eisenhower suffered a heart attack. His personal doctor was also a subscriber to the diet-heart hypothsis and publicly advised people to make relevant dietary adjustments to cut down on their risk of a heart attack. White was a public supporter of Keys, which perhaps led to him securing significant funding ($200,000) in 1956 for the “first multicountry epidemiological undertakings in human history.” (5)

The Seven Country Study

Eager to prove his theory, Keys went on to conduct an epidemiological (population) study using data from 22 countries. Keys plotted the data using the average amount of fat as a percentage of calories in the diet of the countries on one axis and the number of deaths per 1000 from heart disease on the other.


All of the countries from which Keys had data.

1. Australia, 2. Italy, 3. Canada, 4. Ceylon, 5. Chile, 6.Denmark, 7. Finland, 8. France, 9.West Germany, 10. Ireland, 11.Israel, 12. Italy, 13. Japan, 14. Mexico, 15. Holland, 16. New Zealand, 17. Norway, 18. Portugal, 19. Sweden, 20. Switzerland, 21. Great Britain, 22. USA


The complete data set from 22 countries shows no obvious correlation between saturated fat consumption and rates of heart disease. So as all good scientists do, Dr Ancel Keys omitted the data that did not conform to his hypothesis. Yes, he manipulated his findings with seismic implications. Rather than publishing all 22 countries from his research he just included the seven that fitted with his theory. This study then became known as the Seven Country Study, which went on to shape dietary habits in much of the Western world. It is still cited as evidence that saturated fat causes heart disease today.

The graph above is the data set used in the now famous Seven Country Study on saturated fat. As this version of the data shows, when only certain countries were included there was plausible correlation between fat consumption and heart disease in countries such as America, Australia (high consumption, high rates of disease) and Japan, Italy (low consumption, low rates of disease). However, when data from other countries such as France, Israel and Norway is included it is apparent there isn’t an obvious link. Nevertheless, Keys’ cherry-picked version of the data was the one that became famous and went on to shape beliefs about saturated fat for decades.

 While the most obvious flaw with the data that Keys used in his study was the fact he simply did not include all of the countries that he studied, there were many other issues that have since been identified. For example as Nina Teicholz explains in The Big Fat Surprise, data from Greece covered two populations that had very different diets and very different rates of heart disease. Yet the populations from Crete and Corfu were all lumped together and one level of saturated fat consumption was reported. Again, to suit his research needs Keys had omitted the data that did not conform.

During the same period there were a number of scientists and anthropologists such as George Mann, Pete Arhens and Jacob Yerushalmy who thought there was not enough proper evidence that proved saturated fat caused heart disease. Many of these critics were exploring other potential causes such as sugar and carbohydrate consumption and looking at blood triclyceride (circulating fatty acids) levels as a better marker of health. However, they were silenced by Keys who had a very strong and belligerent way of defending his ideas. The diet-heat hypothesis started to be accepted as common knowledge and the more people (and industry players) that got behind this idea, the more those who challenged it were shut down.


The fear of saturated fat leads to the Prudent Diet

Despite disquiet in the health community regarding Key’s findings, organisations such as the American Heart Association (AHA) had already jumped on board with the lipid hypothesis from years earlier. The Seven Country Study only further substantiated their claims and if we look deeper a little later on, this body receives funding from industry players that would benefit from the population fearing saturated fat.

In 1961, the AHA published a report that recommended people “could reduce their risks of heart attacks and strokes by cutting the saturated fat and cholesterol in their diets.” It also recommended that saturated fats be replaced with polyunsaturated fats from vegetable oils. This was the first public endorsement of the diet-heart hypothesis by a national body and it turns out had been contributed by Dr Keys himself, who now had a position on the nutrition committee of the body. Naturally, Keys’ view was the one promoted in the report.

In response to the growing body of “evidence” against saturated fat published in the USA, the AHA launched the “Prudent Diet” in which vegetable oils, margarine, cereals and bread were to replace butter, tallow, eggs, cream and other foods that were high in saturated fat. A 1966 study of those on the Prudent Diet showed men that adopted this way of eating had an average cholesterol serum of 220, compared with 250 for those who continued to eat a “meat and potatoes” diet. While the ultimate goal may have been to reduce cholesterol (and we know that this shouldn’t be a goal for non-rabbit humans), 8 subjects on the Prudent Diet died of heart disease, compared with none in the other group. The head of the study, Dr Jolliffe also died from vascular thrombosis prior to the conclusion of the study.

Irrespective of a number of scientists who spoke out against Keys’ theory, as well as the obvious complications with subsequent research on the matter – like the Prudent Diet study, Dr Keys remained influential with the publication of two health books and a position on the AHA board. The AHA, whose funding and reputation was growing rapidly, recommended the Prudent Diet and hence the false reputation of fat and saturated fat as causing heart disease continued to grow. This proved to be a great success for the big food corporations that made vegetable oils, margarines and cereals. Interestingly some of these corporations were listed donors to the AHA, a huge conflict of interest that continues today.

The publication of America’s dietary guidelines

Despite some disagreement within the health and science community at the time, there was generally enough consensus on the saturated fat-heart connection that it could become mainstream policy.  In 1977 the McGovern’s Senate’s Select Committee on Nutrition and Human Needs released the “Dietary Goals for the United States.” Unsurprisingly they recommended a diet low in fat, specifically saturated fat. They encouraged the replacement of saturated fats with vegetable oils and other cholesterol lowering alternatives. Despite there being a lack of consensus about whether the evidence against saturated fat was conclusive enough, in the absence of any controlled studies McGovern fought effectively to defend the saturated fat- heart correlation.

Senator McGovern: They then asked: “Do you think our knowledge about diet and coronary heart disease is sufficient to recommend a moderate change in diet for the population in an affluent society?” Of these 200 doctors, 91.9 percent answered “Yes,” that they thought that we now have enough evidence to recommend a moderate change in diet. They then indicated the order of priority in which those changes should be made: (1) less total calories, (2) less fat, (3) less saturated fat, and (4) less cholesterol. How do you react to almost 92 percent of the doctors who say they favored these moderate changes in diet based on the evidence we now have? (6)

The Senate Select Committee, although analysing the available evidence at the time, was accused of pandering to various interest groups in agriculture and industry. However, despite obvious conflicts of interest the guidelines were published and dissmentiated officially.

In 1984 Time Magazine Published a front cover proclaiming that the AHA and the diet-heart hypothesis was correct and that we should actively avoid eggs and bacon and this attitude has prevailed in America ever since.

UK Dietary guidelines: following America’s fear of saturated fat

Following the American Select Committee’s release of its “Dietary Goals” the UK’s National Advisory Committee on Nutritional Education also developed public UK dietary guidelines. They recommended people reduce their overall fat consumption to 30% of their diet and specifically reduce saturated fats to 10% of calories.

In formulating the UK dietary guidelines authorities used six randomised control trials (RCT) that looked at whether a reduction or modification in dietary fat or cholesterol impacted rates of CVD. Four of the studies look at replacing saturated fats with vegetable oils, one looked at the impacts of a 20% fat diet and one a 10% saturated fat diet. The researchers conducted a meta-analysis of these studies and pooled the results.

Across all of the studies there was no statistically significant correlation between altering dietary fat and cholesterol and deaths from coronary heart disease. Interestingly, there was actually an overall reduction in cholesterol levels in both the control and intervention groups when the data was pooled.

Verbatim conclusions from two of the studies the UK authority used to develop its guidelines:

– 1968 MRC soya-bean oil: “There is no evidence from the London trial that the relapse-rate in myocardial infarction is materially affected by the unsaturated fat content of the diet used.”

– 1978 Woodhill Sydney Diet Heart Study: “It must be concluded that the lipid hypothesis has gained little support from secondary intervention studies. (7)

Official UK dietary guideline were introduced in 1983 despite the absence of supporting evidence. At the time it was “common knowledge” around the world that saturated fat caused heart disease (thanks Dr Keys) and so it was this information that was carried forward.

The NHS website says,

“We are not able to review the methods used by the US and UK government bodies in forming their nutrition recommendations. We also do not know what evidence they considered…. We cannot comment further on how this nutrition guidance may have been produced, or how they may have considered their evidence and formed their recommendations.”

Where the health of the population is concerned, this is simply not good enough. There are still no conclusive studies that show a link between saturated fat and heart disease, yet this is the line that continues to receive attention in relation to shaping our diets. As a result of the popular thinking in America, much of the Western world now has a poor understanding of what actually constitutes a healthy diet. We are fat shy, with serious implications for our health.

The UK government still propagates the idea that saturated fat is bad for you: “A diet high in saturated fat could in fact lead to obesity.” (8)

Final words on our fear of saturated fat

It is simply not good enough that government and the nutrition bodies in which we place our faith continue to perpetuate the lies about saturated fat. The misinformation surrounding fat is dangerous and we need to actively fight against it by choosing to incorporate healthy fats into our diet. Hopefully government and the nutrition bodies we place faith in will catch up soon.

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