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Comment by SoftwareMaven | Hacker News Reader

We've known for a while the risk factor for heart disease is serum SFA levels, not necessarily SFA consumption. What has never been shown is that consuming SFA raises serum SFA; instead, it's been an understood truism held in place by policy and demagoguery. This study is small, but evidence convicting saturated fats was extremely weak to begin with, and we are now seeing positive evidence exonerating it.

If you are interested in learning more about the history of nutrition, I highly recommend Nina Teicholz book The Big Fat Surprise. As others have mentioned, Phinney and Volek's books are a great overview off the science as of a few years ago. Phinney has been doing research on this for 40 years, quite an accomplishment, given how hard it has been to get funding for research that contradicts the policy line of "carbs are critical to survival and fat must be avoided".

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Well, originally thought was valid. If we eat something, there must be more of it in body. Of course, now we see that body is more complicated in case of SFA, but generally assumption works for other cases.

If a cat entered a house, you generally might expect that cat should be inside the house. The reality, as we see, is more complex than that, but generally assumption works, and worked for most of the cases.

I just want to say that please don't blame scientists and policy makers. Everyone's smart after the fact.

> Well, originally thought was valid. If we eat something, there must be more of it in body.

Sadly we replaced saturated fats (eg butter) with trans-fats (eg margerine). We know that trans-fats are terrible. That possibly caused some confusion. We knew people we still having heart attacks, we just thought that they were the group still eating saturated fats.

And now we may have gotten worse: instead of trans fats (really bad!), we now get highly oxidized poly-unsaturated fats as restaurants have moved to seed oils for frying, which don't handle the temperatures nor the time in use very well. Oxidized fats do nasty things in the body, perhaps worse than trans fats.

Bring back the stable saturated fats like coconut oil, palm oil (if sustainably produced), lard and tallow.

If you eat a cat, do you then contain a cat? No, you contain products of digesting a cat. The supposed cause/effect looks like magical thinking in hindsight.

I think the original analogy refutes itself. If a strange cat enters your house, you remove it. Likewise, the human body has plenty of methods for regulating fats, sugars, sodium, etc. Of course, you can overwhelm those regulatory methods, but in general the assumption that there's a linear relationship between what you consume and the chronic levels seems pretty naive.

-- and if multiple strange cats enter your house, you start to think about closing the door.

Interesting that you mention sodium. I've wondered whether the common advice to restrict sodium to reduce blood pressure actually has any effect. It would only work if your kidneys were not effectively regulating your blood sodium.

http://www.marksdailyapple.com/salt-what-is-it-good-for/

According to this (there's a study linked within) salt's effect on blood pressure and other indicators of heart disease seem to follow a j-curve - too little or too much and you're at increased risk.

The conclusions in there are clear as mud... :)

Anecdote, my father has had blood pressure trouble due to both high sodium and low sodium in the past. In the first episode of low sodium, he kept reducing his salt intake thinking that would help. A visit to ER helped fix that notion.

Here's a recent 8 1/2 minute talk by Dr. George Guthrie (MD) on dietary salt.

https://www.drmcdougall.com/health/education/videos/advanced...

He mentions the importance of the potassium-sodium ratio.

Also, a 2008 article from Dr. John McDougall on salt and blood pressure:

"Salt: The Scapegoat for the Western Diet" https://www.drmcdougall.com/misc/2008nl/aug/salt.htm

In the context of most dietary factors on health, salt is probably one of the smaller influences.

Well, originally thought was valid. If we eat something, there must be more of it in body.

Cholesterol is a great example. Your body makes the majority of cholesterol in your system. Diet only contributes a small amount.

Unless you esat a lot, then your body makes relatively little. I love the way our bodies manage cholesterol, including dumping it into the intestines and recycling it if necessary. It's a beautiful example of how well our bodies regulate themselves when fed and tested well. My body has told me it needs 236mg/dL of total cholesterol right now. You couldn't pay me to mess with that.

Well... with sugar for example we know for a long time that there is only about 50deciliters*80mg/DL=4grams of glucose in blood in average healthy adult. As people are eating tons of sugar a day (snickers bar has 27g, half a liter of cola has ~50g, half of it fructose but still) it's clear stuff doesn't just go into bloodstream as we would all die before finishing that snickers bar. Somehow though fat magically getting into blood and clogging arteries was something which was accepted as common sense. I do blame policy makers and scientists as healthy amount skepticism was clearly missing.

If it were just incomplete science, I'd have no problem with the path we've taken, but it wassn't just a case off incomplete science. It was a case of a handful of scientists deciding on a hypothesis, then fitting data to it. When others rightly complained, a campaign of personal attacks began. Those same scientists got themselves into important positions with organizations like the AHA, giving their arguments a strong appeal to authority, not to mention giving them a huge soap box. Even that probably would have self-corrected, except politicians got involved. In the late 70s, the McGovern commission decided everybody needed a low-fat diet, which eventually entrenched the dogma in all NIH-funded studies as well as government provided food programs like school lunches and food stamps.

The really unfortunate thing is these scientists will likely be remembered for this misguided direction, rather than the huge steps they took in figuring out how to even approach nutritional studies in large populations.

As Feynman said, you have to make sure you aren't fooling yourself, and you are the easiest person to fool. I would argue there was (and continues to be) a lot of self-fooling going on in the field of nutrition. Fortunately, it seems to be getting better, perhaps because of the influence of biochemistry and physiology.

That is a poor analogy. The question isn't is the cat in the house, the question is will the cat be in the house tomorrow? How about next week?

>> If we eat something, there must be more of it in body.

That's not scientific thinking. That's more like pre-scientific Ptolemaic reasoning.

If you drink more water, do you fill up with water?

Nina Teicholz's book "The Big Fat Surprise" has gotten good reviews, but so has Thomas Campbell's book "The China Study" ... they both seem well researched, but very at odds with each other.

Nina's is different. Campbell's was trying to prove what you should eat; Teicholz' followed the history of the science to see where it went. The difference is subtle, but significant. Based on what I've seen and read of Campbell, I think he would expect his work to be the last word on nutrition; I think Teicholz would see hers as a beginning.

I recognize my own bias here, though. I think there are serious flaws in the China Study where Campbell reached beyond where the science illuminated. Teicholz isn't trying to prove a conjecture in the same way, so she isn't forced to do that (I think Robert Ludtig and David Perlmutter both did the same thing, so it's not just a function of vegetarian or not).

Edit: I say read them both and decide for yourself. Don't accept either of their conclusions, but follow the science they reference and evaluate it for yourself.

It's funny, but not surprising, to see the "I love science" crowd on HN so eagerly buy into the "all scientists have been wrong about heart disease" myths propagated by journalists like Gary Taubes and later by Nina Teicholz.

Here are some reviews of Nina Teicholz's shoddy work.

http://carbsanity.blogspot.com/2014/05/no-big-surprise.html

http://carbsanity.blogspot.com/2014/05/book-review-big-fat-s...

But Teicholz just follows in Gary Taubes' footsteps. See the numerous problems with that journalist's interpretation of health and dietary science beginning here:

http://plantpositive.com/1-the-journalist-gary-taubes-1/

>What has never been shown is that consuming SFA raises serum SFA; instead, it's been an understood truism held in place by policy and demagoguery