For 50 years, the consensus among physicians was that saturated fats in the diet caused high cholesterol and heart disease. Peer reviewed studies backed the hypothesis. Government set limits to recommended diets and required reporting on content. To this day, the government’s Food Pyramid is largely based on that hypothesis.
But it was never true.
My physiology Professor in Dental School(not a physician) knew it was BS in 1970. But his views were dismissed by the faculty. Nonetheless, he was right and they were wrong.
To be sure, saturated fats are calorie dense, but a small pat of butter on your biscuit tastes as good as a large dollop of margarine.
The point of this is that scientists are subject to groupthink, just like everyone else, so consensus is of little value. Skeptics should not be dismissed or silenced. Because too often, they are right.
8 thoughts on “Consensus and Peer Review”
This statement is particularly striking: “National dietary guidelines have not recognized this new thinking on saturated fats, however, and continue to promote policies based on outdated or insufficient evidence.” It makes me wonder if it might be a bad idea for the government to author national health standards of any kind.
Also, the diet-heart hypothesis was based on nothing more than a poorly developed correlation. Even in the 1950s this should have been a red flag.
It’s worse than that.
When evidence is found that falsifies a scientist’s hypothesis, his proper reaction should be. ‘Yay, we learned something that brings us closer to the truth.’
But scientists are human, and when supported by government, they tend to circle the wagons to defend their disproven theory.
Not just in nutrition but across all government supported research.
Michael Mann’s “hockey stick” graph became the basis for global policy, But Steve McIntyre and Ross McKittrick showed it to be statistically flawed. Radio host Mark Steyn publicized their findings and Mann sued him for libel. After a decade of delays and harassment, Mann dropped the suit rather than produce his data for independent review as ordered by the court. Those are the kind of extremes some scientists will resort to rather than admit their theory was wrong.
The CDC adopted its ‘vaccines for every age’ policy when it was thought that would block transmission, but experience has shown it does not. The policy remains unchanged, even though vaccinating people under 20 is counterproductive.
This trend of fighting to the end rather than abandon a failed theory is the death of science.
RE: “This trend of fighting to the end rather than abandon a failed theory is the death of science.”
A solution might be for more people to learn to think like scientists, although I have no idea how to encourage it. In fact, I’m unsure of my own ability to think like a scientist. Still, a few habits of mind to avoid are:
Judging the value of information or opinion based on its source.
Reducing ideas to their political implications.
Forgetting that the difference between correlation and causation is epistemological.
Imagining that publication (or peer review) confers legitimacy.
Assuming that others know what you mean without telling them. Corollary: Assuming you know what others mean without asking them.
Here is a link to the Mayo Clinic. According to them, diet is still an important part of controlling cholesterol levels. Avoid trans fats, add in fiber and other foods that provide “good” fats.
Similarly at Harvard.
And the Cleveland Clinic.
I get the impression that the science was not so much wrong for medical advice, but rather we have learned more about the why’s of how it works.
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The ‘good fats’ are the saturated fats the hypothesis discouraged and the ‘trans fats’ are the ones recommended as replacements.
That said, all fats are calorie dense and should be limited for that purpose, but dietary fats within the caloric limits have no effect on cholesterol.
Note that your cites are mostly about limiting total fat and eating other foods that help control how the body uses fats,
None of them support the outdated notion that eating high cholesterol or saturated fats result in high blood cholesterol .
Only the government clings to that.
“ Saturated fats — such as those in meat, butter, cheese and other full-fat dairy products — raise your total cholesterol. Decreasing your consumption of saturated fats to less than 7 percent of your total daily calorie intake can reduce your LDL cholesterol by 8 to 10 percent.
Trans fats, sometimes listed on food labels as “partially hydrogenated vegetable oil,” are often used in margarines and store-bought cookies, crackers and cakes. Trans fats raise overall cholesterol levels. The Food and Drug Administration has banned the use of partially hydrogenated vegetable oils by Jan. 1, 2021.”
I am confused. Are they also wrong?
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Did Mayo provide any evidence that saturated fats, within the caloric limits, raise cholesterol?
…”within the caloric limits”…
That is probably the key part of your question. The only person I know who actually tracks her caloric intake DAILY is my wife. I could take pictures of her mini-legal pads that she uses to prove it, but its tedious in my book.