[_yb2s]

This... our understanding of biology is way too primitive to have a meaningful mechanistic understanding of what is healthy, and what is not. Most of the nutrition advice is based on simple observational correlations that are assuming a cause and effect that just isn't there. People with high cholesterol also tend to have more cardiovascular disease, but it turns out eating cholesterol and fat doesn't actually increase risk of cardiovascular disease. People who eat a lot of fish tend to have better health outcomes, but it turns out taking fish oil does not reproduce those outcomes, and so on and so on.

Scientific nutrition is mostly just "scientism" - an irrational overconfidence bordering on a religious faith in unfounded assumptions based on observational studies, without admitting what we don't know.

I think it is reasonable to avoid trying to make decisions about diet based on this stuff, but I think ideas like the paleo diet or evolutionary nutrition make a lot of sense- eat diets similar to those that humans have eaten safely for a long time, as those are what we are likely adapted to. Interestingly though this itself is massively diverse: there are hunter gatherer societies with almost every diet composition imaginable: from artic diets that are high protein and fat but nearly zero carb, to cultures like the kitavans whose diet is very high carb and low protein. Our metabolism is very adaptable and any diet that is mostly fresh nutrient dense foods from plant and/or animal sources is probably about equally healthy.

Ironically, the stress of worrying constantly about if your food is optimally healthy, is probably more harmful to your health than anything typically considered unhealthy.

[hombre_fatal]

Even if you throw out the research that you mention, you'd still have to contend with https://en.wikipedia.org/wiki/Mendelian_randomization which converges with that research and shows that ApoB is an independent causal factor for CVD, like https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7611924/ (random google result). And saturated fat increases ApoB. And Mendelian randomization over genes that increase the saturated fat -> cholesterol or ApoB relationship, or cholesterol and ApoB independently, result in more CVD.

The evidence and scientific consensus are still against your wishful thinking. Though these days with algorithmic doom-scroll feeds it can feel like there is no consensus.

I follow a lot of evidence based nutrition accounts on Twitter yet I still get recommended quacks like Shawn Baker and Nina Teicholz (carnivore diet charlatans) who make the same points you make to story-tell away the inconvenient truth. And I specifically avoid anti-science quackery. So I can imagine what the average person is seeing and why it seems like the science is reversing.

[_yb2s]

Nutrition has become the same as politics- since I don’t agree with what you think, you’re assuming I’m part of the “opposite side” which is absolutely untrue in this case.

Being able to come up with a single plausible mechanism like you posted makes sense in isolation, but not when you consider the bigger systems level picture of a whole organism and chemically complex foods, and the fact that anyone who has taken undergrad biochem could come up with a dozen that are equally plausible and consistent with the literature but in the opposite direction. I’ll mention Chris Masterjohn, not because I agree with him, but because he’s a nutrition guru that is great at coming up with dozens of plausible mechanisms that argue against what you are saying. That type of mechanistic reductionist reasoning is the main reason nutrition advice is so falsely overconfident and mostly nonsense.

[NumberWangMan]

I don't think that the scientific consensus on nutrition as unsettled as you say. As an example, there are a lot of people making money selling various diets as well as promoting uncertainty and doubt around the issue, but there seems to be pretty definitive evidence in favor of cholesterol and fat increasing cardiovascular disease risk. People love to misrepresent studies, or cherry-pick poorly designed studies, and use them to claim that the consensus is wrong.

I'm not talking about observational studies either, but actual controlled feeding trials where they put you on a strictly controlled diet for a period of time.

Even if you look at what humans are evolved to eat -- evolution puts selective pressure on reproductive fitness. As a process, it does not put any pressure on you to live a long time, as long as you reproduce successfully (which is why insects like the mayfly can even exist). So looking at what primitive people ate does not really give us information about what is healthy if you want to live a long time (aside from avoiding things that are obviously immediately poisonous).

Even hunter gatherer tribes that eat a meat-and-dairy-heavy diet like the Maasai have been examined and have pretty significant cardiovascular disease -- but they are also so ridiculously active their blood vessels are much wider than people with a modern sedentary lifestyle, and that mostly balances out the narrowing from arterial plaque. Native people who eat a traditional diet heavy in whole grains, legumes, and tubers for calories have them beat by a mile when it comes to arterial health.

[_yb2s]

I strongly disagree- I have a related academic background and have read the nutrition literature extensively myself, attend nutrition conferences, etc. and don’t agree there is convincing evidence for what you are saying. This narrative is just one of the cherry picked diet fads.

Moreover, saying the history of human diets gives us no information is just incorrect. It’s not the final word on nutrition, but it is the obvious Bayesian prior. When you raise any animal in a zoo, or culture a microbe in a lab the first thing you do is mimic its natural environment as well as you can, at least until you understand more.

Personally- I am much more interested in quality of life aka things like “reproductive success” than lifespan in my own health, but I am also skeptical that they are at odds. I am an active person and enjoy being physically strong, high energy, etc.

[hombre_fatal]

Well, the prior is that our ancestors had to survive on what was available, not live optimally healthy lives even during their reproductive years.

At the end you imply that your preferred diet (presumably high saturated fat, low carb, low fiber) makes you stronger and gives you more energy than the alternatives. But that's not the trade-off nor implication that can be drawn from our ancestors eating what was available to them for survival. We can do better in 2024 than use narratives about the past to dictate how we eat today.

You should listen to this debate between Matthew Nagra and Anthony Chaffee: https://www.youtube.com/watch?v=3FFV0w55k2I -- You will find yourself making the same points as Chaffee, but go see if you are as equally stumped by the evidence that Nagra provides.

[throwup238]

> Well, the prior is that our ancestors had to survive on what was available, not live optimally healthy lives even during their reproductive years.

That's true but our ancestors weren't some poor apes constantly on the verge of starvation scrounging for any kind of food they can find. If contemporary tribes are any indication, in the tropics food was very plentiful and their diet was diverse, long before they started domesticating animals and cultivating plants. These ecosystems support hunter gatherer tribes to this day, the last few remaining holdouts from agriculture and pastoralism. That allowed archaic humans to spread as far east as Indonesia more than a million years before they made it north of the Mediterranean.

[_yb2s]

Life also had to survive with oxygen poisoning… but we’ve been adapting to it for a while and we are pretty dependent on it at this point.

I don’t follow any diet fads or protocols, and don’t do lc/hf as you are implying, other than avoiding processed food in favor of actual plants and animals. However, I am a competitive strength athlete, and do keep protein high when preparing for a competition- because I can directly measure the positive results in my performance. Carbs and fiber seem to be just as important- even sugar e.g. from fruit is a great fuel for replenishment of glycogen and reducing stress from intense exercise. I have friends that are masters strength athletes in their 70s and 80s and they have incredible quality of life for their age, simply because they are still strong and active.

I’ll take a look at the video, sounds interesting.

[nradov]

That is misinformation. Cholesterol is not a nutrient of concern. The molecules are too large to be absorbed through human digestive systems. Almost all of the cholesterol in our bodies is endogenously produced.

https://peterattiamd.com/understanding-cardiovascular-diseas...

https://health.gov/our-work/nutrition-physical-activity/diet...