[jorblumesea]

Says you? because that's not what cardiologists, nutritionists and doctors say. around the world. there's a ton of real, good science from many countries that show a very clear link between increased saturated fat intake, CVD and LDL-C levels. It's not really in question.

You are essentially hand waving away 80+ years of scientific studies and data because...you said so?

> you really shouldn't trust a doctor about any of this stuff any more than you should trust the latest health influencer crackpot.

This is an insane take and thoroughly discredits anything you have to say. Science has some basis in reality, even if it is somewhat flawed. The idea that we should throw out all science food guidelines because it's not perfect is completely crackpot.

I have no idea why nutrition brings out the crazy left field engineer types but it's a common pattern.

[tsimionescu]

In any other domain, I would agree with you 100%. But nutrition science really is that bad, in my experience and opinion. With some exceptions (e.g. the need for vitamins to avoid things like scurvy, or the relationship between salt intake and blood pressure), even long-standing nutrition beliefs and practices have been overturned (e.g. consumption of cholesterol, or the discovery of the role of dietary fiber), and some of the newer research is likely to overturn others (e.g. with the role and diversity of gut microbiomes, it's likely other nutrition advice will depend to some extent on your specific microbiome).

The reason for this is fairly simple to see: the methods of science that work so well in other areas of biology are completely impractical in nutrition because of

1. The difficulty of ascertaining and maintaining compliance with a specific diet for a long term study

2. The very long-term effect of some food choices

3. The unknown degree of inter-personal variance in food consumption

4. The expected low effect size of dietary recommendations

5. The huge variety of possible dietary effects

6. The huge amount of possible confounding factors in any population-level study

As you'd expect from this combination, the only effects we really have good science about are those that are relatively fast acting (e.g. salt intake increases BP in less than a day) or have very strong effect sizes (e.g. lack of vitamins or certain amino-acids produces severe diseases). For things like life-long effects, or even effects over multiple years, especially where the correlation is slight, you're left with very unclear science where the unknown possible confounding factors dominate any conclusion.

Edit to add: even today, there is a clear disconnect in nutrition science between people who advocate mostly for relatively simple guidelines and the avoidance of processed foods, usually recommending a preference for vegetables over animal-based products; and the older style of guidelines that you suggest, that say a grilled steak is much worse for you than, say, a stevia-sweetened granola bar you'd buy in a super market.

[themk]

Dietary cholestrol hasn't really been overturned, but sure there is some nuance. Some people do respond badly to dietary cholestrol (like you said, individual advice is sometimes required), but dietary cholestrol is also not a linear response afaiu. That is, if you eat one egg a day, you may as well eat 4, but if you can completely eliminate dietary cholestrol it could make a difference. So, many guidelines don't bother with suggesting it, because it's too hard to eleminate it to the point of mattering for the average person.

All that to say, the science isn't wrong, but the practicalities influence the advice.

[D-Machine]

Nutrition science is not science in almost any of the ways a real science needs to be, and there is almost zero "real, good science" to be found in it. The reasons this statement is true (as well as the precise qualifications of the exceptions to this) are well laid out by tsimionescu in response to your post.

The measurement, control, confounds, and even basic concepts are atrocious here, this is possibly the only field as bad as or even worse than e.g. social psychology. And this is all ignoring the massive economic interests involved.

It is in fact only science illiteracy that would lead one to think nutrition science is a serious science. At the most absolute charitable, it is a protoscience like alchemy (which did have some replicable findings that eventually led to real chemistry, but which was still mostly nonsense at core).

[aldarion]

https://pubmed.ncbi.nlm.nih.gov/28442474/ https://bjsm.bmj.com/content/51/15/1111

Matter of the fact is that the entirety of belief that saturated fat "clogs the arteries" was based on the epidemiological studies which failed to adjust for other risk factors such as trans fat intake, intake of processed foods, and many more.

We should not throw away "80+ years of scientific studies and data" because... said "80+ years of scientific studies and data" do not exist. Not a single actual study had ever been made. The best we have are epidemiological studies, and these have massive issues.

"This is an insane take and thoroughly discredits anything you have to say. Science has some basis in reality, even if it is somewhat flawed. The idea that we should throw out all science food guidelines because it's not perfect is completely crackpot.

I have no idea why nutrition brings out the crazy left field engineer types but it's a common pattern."

It is not an insane take, you are just being a dumbass. Doctors do not have any training in nutrition. When I asked my doctor - doctors, actually, plural - for dietary advice, literally all of them told me "I don't have knowledge to advise you on that, figure it out on your own".

Science has basis in reality, yes. But doctors aren't scientists.