The experts and authoritative institutions are clear: you should eat a low-fat diet and take drugs to reduce your blood LDL cholesterol to safe levels in order to make your heart healthy. Here is their advice about saturated fat and about blood cholesterol. The capital-E Experts are wrong. They were wrong from the beginning. There was never any valid evidence in favor their views, in spite of what you might read. The quantitative and biochemical evidence is now overwhelming. Here is my summary of the situation. In this post I’ll cover more of the evidence.
Origins and growth of the saturated fat – cholesterol – heart hypothesis
How did such a bogus theory get started? An experiment with intriguing results was one start. Here's a summary:
The hypothesis harks back to the early part of the twentieth century, when a Russian researcher named Nikolai Anitschkow fed a cholesterol [animal fat] rich diet to rabbits and found that they developed atherosclerosis (hardening of the arteries, the process which in the long run leads to cardiovascular disease). … Rabbits, being herbivores, normally have very little cholesterol in their diets, while humans, being omnivores, generally consume quite a bit of cholesterol. Regardless, the data was suggestive, and led to the hypothesis being formulated.
A paper titled “How the Ideology of Low Fat Conquered America” was published in the Journal of the History of Medicine and Allied Sciences in 2008. Here is the abstract:
This article examines how faith in science led physicians and patients to embrace the low-fat diet for heart disease prevention and weight loss. Scientific studies dating from the late 1940s showed a correlation between high-fat diets and high-cholesterol levels, suggesting that a low-fat diet might prevent heart disease in high-risk patients. By the 1960s, the low-fat diet began to be touted not just for high-risk heart patients, but as good for the whole nation. After 1980, the low-fat approach became an overarching ideology, promoted by physicians, the federal government, the food industry, and the popular health media. Many Americans subscribed to the ideology of low fat, even though there was no clear evidence that it prevented heart disease or promoted weight loss. Ironically, in the same decades that the low-fat approach assumed ideological status, Americans in the aggregate were getting fatter, leading to what many called an obesity epidemic. Nevertheless, the low-fat ideology had such a hold on Americans that skeptics were dismissed. Only recently has evidence of a paradigm shift begun to surface, first with the challenge of the low-carbohydrate diet and then, with a more moderate approach, reflecting recent scientific knowledge about fats.
The early chapters of The Big Fat Surprise book provide a good summary with details of the rise to dominance of the low-fat & cholesterol-is-bad theory.
Strong Data Showing that Saturated Fat is Good
There were problems with the diet-heart hypothesis from the beginning.
The first chapters of The Big Fat Surprise have summaries of studies that were made on peoples around the world who subsisted almost exclusively by eating animals and/or dairy, all of them strongly preferring fatty organs over lean muscle.
A Harvard-trained anthropologist lived with the Inuit in the Canadian Arctic in 1906, living exactly like his hosts, eating almost exclusively meat and fish. “In 1928, he and a colleague, under the supervision of a highly qualified team of scientists, checked into Bellevue Hospital … to eat nothing but meat and water for an entire year.” “Half a dozen papers published by the scientific oversight committee that scientists could find nothing wrong with them.”
George Mann, a doctor and professor of biochemistry, took a mobile lab to Kenya with a team from Vanderbilt University in the 1960’s to study the Masai. They ate nothing but animal parts and milk. Their blood pressure and body weight were 50% lower than Americans. Electrocardiograms of 400 men showed no evidence of heart disease, and autopsies of 50 showed only one case of heart disease.
Similar studies and results came from people in northern India living mostly on dairy products, and native Americans in the southwest. There were many such studies, all of them showing that the native peoples, eating mostly saturated fat, were not only heart-healthy, but free of most other modern afflictions such as cancer, diabetes, obesity and the rest.
Of course the question was raised of other factors that might lead to these results. The questions have been answered by intensive studies. For example, some formerly meat-eating Masai moved to the city and lost their health. For example, Inuit who changed their diet to include lots of carbohydrates supplied by government were studied by doctors who determined they lost their health.
From the book:
In 1964, F. W. Lowenstein, a medical officer for the World Health Organization in Geneva, collected every study he could find on men who were virtually free of heart disease, and concluded that their fat consumption varied wildly, from about 7 percent of total calories among Benedictine monks and the Japanese to 65 percent among Somalis. And there was every number in between: Mayans checked in with 26 percent, Filipinos with 14 percent, the Gabonese with 18 percent, and black slaves on the island of St. Kitts with 17 percent. The type of fat also varied dramatically, from cottonseed and sesame oil (vegetable fats) eaten by Buddhist monks to the gallons of milk (all animal fat) drunk by the Masai. Most other groups ate some kind of mixture of vegetable and animal fats. One could only conclude from these findings that any link between dietary fat and heart disease was, at best, weak and unreliable.
One of the foundational studies in the field is the Framingham Heart Study, started in 1948 and still going on.
In 1961, after six years of study, the Framingham investigators announced their first big discovery: that high total cholesterol was a reliable predictor for heart disease.
This cemented things. Anything that raised cholesterol would lead to heart disease. The trouble came thirty years later, after many of the participants in the study had died, which made it possible to see the real relationship between cholesterol and mortality due to heart disease. Cholesterol did NOT predict heart disease!
The Framingham data also failed to show that lowering one's cholesterol over time was even remotely helpful. In the thirty-year follow-up report, the authors state, "For each 1% mg/dL drop of cholesterol there was an 11% increase in coronary and total mortality."
Only in 1992 did William P. Castelli, a Framingham study leader, announce, in an editorial in the Archives of Internal Medicine:
In Framingham, Mass, the more saturated fat one ate ... the lower the person's serum cholesterol ... and [they] weighed the least.
Game over! No wonder they've kept it quiet. And not just about heart health -- about weight loss too!
Here is an excellent article with references to and quotes from many journals. Here is the introduction:
Many large, government-funded RCTs (randomized, controlled clinical trials, which are considered the ‘gold-standard’ of science) were conducted all over the world in the 1960s and 70s in order to test the diet-heart hypothesis. Some 75,000 people were tested, in trials that on the whole followed subjects long enough to obtain “hard endpoints,” which are considered more definitive than LDL-C, HDL-C, etc. However, the results of these trials did not support the hypothesis, and consequently, they were largely ignored or dismissed for decades—until scientists began rediscovering them in the late 2000s. The first comprehensive review of these trials was published in 2010 and since then, there have been nearly 20 such review papers, by separate teams of scientists all over the world.
Far from believing that saturated fat causes heart disease, we can be quite certain that it's positively healthy on multiple dimensions to eat it -- it's people who don't eat enough saturated fat who end up overweight and sickly!
Sadly, there are still Pompous Authorities who assure us with fancy-sounding studies that we really should avoid eating fat. This study from 2021 dives into just such a fake study -- a RCT (random controlled trial) study -- that purported to show that eating fat remains a bad idea. Wrong. Here's the summary:
Hiding unhealthy heart outcomes in a low-fat diet trial: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial finds that postmenopausal women with established coronary heart disease were at increased risk of an adverse outcome if they consumed a low-fat ‘heart-healthy’ diet.
These books by Dr. Malcolm Kendrick dive in more deeply and are moreover a pleasure to read. Among other things, The Clot Thickens explains the underlying mechanisms of arteriosclerosis (blood clots, heart disease) and what actually causes them.
Here are several articles with evidence from many scientists on the subject of saturated fat.
Latest Results
The evidence continues to pour out -- not that the vast majority of "professionals" change their tune about what constitutes a healthy diet. Here is a new paper published by Oxford written by cardiologists.
The authors asked exactly the right question:
Cardiovascular disease (CVD) is the leading global cause of death. For decades, the conventional wisdom has been that the consumption of saturated fat (SFA) undermines cardiovascular health, clogs the arteries, increases risk of CVD and leads to heart attacks. It is timely to investigate whether this claim holds up to scientific scrutiny.
They found and went through more than ten years of recent published studies, p through 2021. Here is their conclusion:
Findings from the studies reviewed in this paper indicate that the consumption of SFA is not significantly associated with CVD risk, events or mortality. Based on the scientific evidence, there is no scientific ground to demonize SFA as a cause of CVD. SFA naturally occurring in nutrient-dense foods can be safely included in the diet.
Here is a summary in a journal of the history and latest research on the subject, focused on the national nutrition guidelines, which maddeningly fail to reflect the facts about this subject.
What more needs to be said?
Conclusion
This is an incredibly important issue regarding the health of people. It's also an in-progress example of the difficulty of shifting a paradigm, even when the evidence against the dominant paradigm (avoid eating saturated fat, use drugs to keep your cholesterol low) is overwhelming. Could it be possible that billions of dollars a year of statins and related cholesterol-lowering drug sales has something to do with it? Then again, when was the last time you heard a prestigious Expert or institution say "Sorry, we were wrong, we'll try hard not to blow it again; we won't blame you if you never trust us again."