LW's take on nutrition?

I've been watching for several years now (I adopted the diet myself in 2010), and all of the negative critiques tend to fall into (a) critiques from non-experts, (b) critiques from experts in unrelated fields, (c) health experts who agree that his recommendations have merit, but that they're impractical for the general public to follow.

I produce for you a book written by a relevant expert with ~2.5 times as many references as The China Study (2034 vs 758) who advocates eating an ancestral diet (lean unprocessed meat/fish, fruit, nuts, vegetables/root vegatables) (1). A list of individuals with relevant graduate degrees who more-or-less agree with him can be found in this list of speakers at a paleo conference he spoke at. His recommendations are at least as similar to the recommendations the Mayo clinic returned for me as Campbell's.

That is, I can make a symmetrical argument for a significantly different diet (2), complete with experts and evidence and stuff.

So, to address your questions directly: you should believe that nutrition is a young and complex field, and therefore shouldn't have everything all figured out; my take is that you may do well to replace grains with root vegetables, since that's something everyone agrees is good (plus they're really tasty!); this isn't good enough to inform your dietary choices because I just used a symmetrical argument for a diet that has nonnegligible discrepancies with the diet Campbell recommends; and I don't know how to dig out a signal that experts, to my knowledge, haven't managed to dig out without becoming an expert.

(FWIW, I spent about 5 years as a vegetarian, followed by 1.5 years doing the paleo thing, and now subsist entirely off DIY soylent, which combines the virtues of deriving all its protein from animal sources and being processed.)

(1) Interestingly, Campbell's and Lindeberg's diets can be eaten simultaneously, and this intersection is 100% in-line with what the Mayo clinic recommended me. The difference is that Campbell allows grains and beans, and Lindeberg allows (unprocessed) lean meats, fish, and eggs.

(2) Again, there's substantial overlap, but also substantial disagreement: Lindeberg, for instance, observe the Inuit derive something like 98% of their calories from animal sources and are virtually untouched by Western disease, and concludes that very high consumption of (unprocessed) animals is perfectly fine, whereas Campbell claims that humans should eat minimal amounts of animal.

Largest effects with the smallest error bars around them: Processed meats bad, fruits and vegetables good, fish and nuts good.

Everything else is significantly smaller effect size or large error bars AFAIK.

I know very well a registered dietitian who deeply knows her stuff. She's explained quite a lot to me, and given me considerable knowledge (it helps that my field is chemistry, and while biochem is different than what I do it's not completely alien).

Unfortunately I can't say much about nutrition in one single post. Like so many things, it's a really complex and rich science and to really know something about it would take years of education on the subject. As you may imagine, everything comes with lots of exceptions and qualifiers. My recommendation if you really want to learn this stuff is to talk to a registered dietitian (any quack can call themself a neutritionist, but RD is a protected title), or read recent academic textbooks (NOT popular books) on nutrition.

About the subject matter in the main post, from my knowledge, meat and heavily processed foods tend to be more in the territory of things that are worse to eat a lot of. I can pretty certainly say it's true that many people would do better to eat considerably less of that stuff than they do.

Speaking from my area of expertise now, I'll say that it's pretty silly from a thermodynamics standpoint to eat meat. You can do fine as a vegetarian, and raising plants to eat is significantly more energy efficient than raising plants to feed animals to eat. Animal raising leads to a considerable amount of energy waste, as well as material pollution. I don't have the numbers on hand, but it's enough to be a significant factor. So what do I do? I don't eat meat very often.

(6.) The natural world can be complicated, and scientists have limited tools to investigate and a lot of incentive to oversell.

It is difficult to arrange RCTs for nutrition -- and so you must be very careful. My advice is to engage with their actual citations.

Diet doesn't seem to be a one size fits all proposition.

Different people have different metabolisms and different gut flora profiles.

It's more likely that everyone has a perfect diet that would be just right, but just for them. The particular bacteria in your gut might be very adept at turning lactose into calories, and not so in others. Things like this would help prescribe foods, and in certain cases where your flora are too helpful, maybe a fecal transplant from a skinny person.

When we have enough calories to meet our needs every day, we have to find ways to help people whose only way to stay thin is to walk around feeling starved, which used to be adaptive but now isn't.

In U.S. academia, "Professor Emeritus" is a title given to professors who are retired.

My view of nutrition is basically option 2. "Nutrition science" as it exists today seems to be primarily an attempt to study subtle, complex effects using small, poorly-controlled samples. There are basic facts about nutrients that are fairly well supported, but I have never become convinced of the superiority of any "diet" based on the supposed evidence for it.

I think the answer is mostly two, with a little side of four. Nutrition science is very difficult to perform correctly, because of the difficulty and cost of randomized controlled trials of diets. In particular, the China study was not controlled, and it was performed via surveys (which have a reputation for being inaccurate in diet studies). Added to that is the fact that food isn't really about food. It's deeply intertwined with our sense of personal identity and culture, and that leaves you with many researchers stretching their relatively weak evidence a little bit further than is warranted. Once you get as far removed from the actual science as recommendations from the FDA or Harvard School of Public Health, there is virtually no room left for nuance, and they are already making recommendations from a public health perspective, which is not the perspective you seek.

With respect to confirmation bias, I suspect there is some of that going on. Specifically, you say, "There are lots of people who are PhDs of exercise, anthropology, or economics who criticize his recommendations, but I have a hard time finding a mass gathering of nutrition scientists coming out of the woodwork to shoot down his recommendations." There are probably not "mass gatherings of nutrition scientists" who disagree with the China Study, but there are mass gatherings of experts in medicine and various biological fields (and maybe the odd nutrition scientist) who would probably disagree with the China Study. Googling "paleo conference" I could easily find several such mass gatherings. So you aren't wrong, but you are implying more with your selection of outsider expertises than is warranted (exercise, anthropology or economics, rather than doctors, biologists, etc.).

With respect to the object-level consideration, I recommend you read Stephan Guyenet's recent series of articles on meat Is Meat Unhealthy?, which considers both positive and negative factors of eating meat. He is not a nutritional scientist (he is a neurobiologist), but he is by all appearances a careful scholar. You can read the summary first if you want to see his ultimate conclusions, which don't strongly support either the "vegan" or the carnivorous sides of the debate.

However, with respect to the China Study itself, he only touches on it in this series thusly:

The China Study

The China Study was a massive ecological study relating diet and lifestyle to chronic disease risk in China. It has been invoked by researcher and vegan diet advocate Colin Campbell to support the idea that animal foods promote cardiovascular disease and cancer, even in the small quantities that were typical of the regions studied. After having reviewed the study data, the publications based on it, and the various commentaries on it, it appears relatively clear that the China Study does not support the conclusion that meat consumption is associated with cardiovascular disease or cancer risk (17, 18, 19, 20, 21). Everyone seems to agree on that, except Campbell and certain other vegan diet advocates. I won't discuss the China Study further.

And elsewhere has criticized it on methodological grounds (e.g. here)

Reading a little bit, I'm reminded that there's more than one party involved here.

Now, I'm no scientist, but you don't have a diet without a person. We can correctly assume that you can't go on without one or the other. Coming from this way, we can make an rather simple observation that not every diet is the same, and that not every person is the same. While the diet part is extremely important, it's not as important as the person, as ultimately the diet is digested inside the person. Considering every person is different, would it be a far stretch to say that their diet should be different, too?

This is a simple observation I made just now. I've noticed an dispropronate weight on people's diet. It's not entirely incorrect - there is some common ground between people. But people are micro/macro-different, healthy is still a vague term (some sort of close-to synonym with nutriential value) and even my observation might not include all of the parties involved. But I think it's a good general look in the right direction.

So, if we were to think about nutrition, we should first clear the things with the largest weight so we have a good base to stand on. And we incrementally build the pyramid from there.

Why doesn't your list of "things I've considered" include an option like, "Nutrition science is real science, and Campbell's work is correct"?

When talking about diet, some people are focused on health and some are focused on weight loss. These are related, but not identical. I'm assuming you're focused on health because of your phrasing.

My view is that the Mayo Clinic's food pyramid recommendations come closest to orthodox theory. The top alternative is probably Harvard's nutrition source. Neither of those two sources strike me as politically influenced. I read a lot of Aaron Carroll as I think he does a pretty balanced job of discussing a lot of nutrition research. He recently argued against the claim that heavy red meat consumption is as dangerous as people claim.

Vegetables and fruits have ridiculously good nutrient density. From that perspective Campbell is correct to focus on them. But most nutritionists would argue you should eat other foods to obtain the other nutrients. There is also some concern over claiming bigger health benefits than can be reliably demonstrated. Overall, his views come close enough to orthodoxy that I doubt it's worth worrying about too much, and his biggest difference is in the way he talks about the diet (telling people 0% instead of telling them 10%), so your views are pretty much in line with mine.

Recommendation summary:

Thus far it seems:

Limit meat consumption to >10%

Eat as much fruit as you like

Don't eat grains, replace them with root vegetables

Anything else?

No one has any gossip about overly liberal maximum residue limits? Official documentation suggests Aus and Nz food safety authorities tend to be conservative, but we're a whole another level of conservative and risk averse here :)

Based on what I know about the words "professor" and "emeritus" and "cornell", I assume this is written by an authority in the field of nutrition.

The value of being an authority in a field is that you can accurately convey the consensus within that field. Whenever consensus within a field does not exist, the ancient injunction against "argument from authority" remains true. The "authority" derives not from the authoritative individuals themselves, but the collective wisdom of the field to which they've been exposed.

1. Science is crap. Don't believe expert predictions about the natural world.

Science isn't crap - it's just that when science is weird and inconsistent and wrong it's obvious and everyone notices because science has better epistemic hygiene practices than non-science methods of discovering things. You're just overestimating the degree of accuracy and agreement science aught to have.

I might have the specifics of this story wrong, but once upon a time, scientists (correctly) showed that blood cholesterol is correlated with bad things. So people stopped eating more than 1-2 eggs a day. Now we know dietary cholesterol doesn't directly control blood cholesterol and you can eat lots of eggs and your LDL won't rise in a meaningful way. That doesn't make the original findings wrong, it just means the resulting interpretation was wrong. The original scientists weren't being dumb, it was perfectly reasonable interpretation to make.

The China study found some probably correct things assuming they followed protocol and did statistics well, and now they're interpreting it to mean "go vegan". As a consumer of primary research, you should ask yourself if the findings -> practical interpretation link is reasonable.

nutrition science is crap

It's really not significantly different from "we thought there was Aether, and now we don't", but in fields like economics and psychology and nutrition people notice more when you mess up, because laymen understand enough to know what it means to make a mistake - Everybody votes, deals with minds, and eats, but most people don't understand the implications of their not being an aether. .

But, yeah - scientists are people, and some fields tend get more contaminated with personal biases that the researchers might have acquired entirely outside the laboratory. This can inform the types of questions they study, confirmation bias, bias in the interpretation of the data, and so on. Also, whenever an issue of public policy is at stake, I imagine special interests groups get involved.

Why isn't this good enough to inform your dietary choices?

The evidence certainly does inform my hypothesis, but that's not the same thing as agreeing with the author's interpretation. (I don't say "choices", because my interest is mostly academic and I'm not particularly diet conscious in my personal life, and I do factor in moral concerns with respect to meat, which makes my actual diet not particularly in line with what I think is nutritionally optimal.)

The important thing is to inform ones views based on the evidence gathered, rather than trusting the researcher to interpret their own evidence.

I accept that chinese diets are likely superior to Western diet. Leafs, shoots, roots, fruits, nuts, and the like are all extremely, extremely important. When meat replaces or otherwise funges against those foods (as you'd expect it to given limited calories per day) meat is bad. The average American lives on meat and grains, skipping the fruits and veggies, and that's no good. The average American vegetarian will probably be healthier than the average American omnivore for this reason, even controlling for caloric intake. The average American would probably benefit from going vegetarian, not to mention the various moral horrors and environmental damage meat entails. It's not surprising that we see the same trend in China.

But, well - none of that means that vegan is nutritionally optimal. Hunter gatherers, lacking grains and dairy to provide calories, would have probably "maxed out" the benefits leafs, shoots, roots, fruits, nuts, and other plants despite also eating lots of meat. The Inuit pretty much just eat meat and do fine. (Don't try it at home - the Inuit can only do this through judicious consumption of organ meats, which are glycogen rich and nutrient dense. They actually often discard the lean muscle meat, probably because they've intuitively grasped the macro-nutrient ratio problem it would pose.)

When you look at the evidence provided from the China study - not the interpretations, just the evidence - there's very little room for suggesting that hunter-gatherer diets are suboptimal.

Assuming you don't plan to become an expert in the field of nutrition yourself, what's a better way to inform your dietary choices?

There's no way out. I can say "Eat a balanced diet, with natural real foods" or whatever but the true meaning of "balanced" and "natural" is a lot more controversial than it seems at first. If you don't do your research you are down to guesswork, and after you do your research you are still mostly down to guesswork due to how little we really know.

FWIW, having a totally optimal diet is probably not extremely important in the grand scheme of things. For all practical purposes you'll be just fine so long as (1) your calories are okay, (2) your macronutrient ratios are not horribly awful, (3) you have no obvious symptoms of micronutrient deficiency, and (4) you exercise. Everyone agrees on those four and that you should eat fruits and veggies. Beyond that, it's all controversial and I doubt the additional worrying will really buy you that many extra years of quality health when one factors in the likelihood of choosing the correct arguments among the controversy. (Outside view. Inside view, I totally think I'm right in choosing the "take cues from hunter gatherers" thing.)