(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.
(6.) The natural world can be complicated, and scientists have limited tools to investigate and a lot of incentive to oversell.
Agree that the world is complicated. Could you go into more detail about incentive to oversell? Do you mean they need to promise groundbreaking results to close funding?
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.
I'm specifically trying to avoid weighing the actual science or studies myself, because I don't think nutrition is linear enough for me to just dive in and read contradictory studies and start making informed decisions about my diet. So, all I'm really electing to do here is try to valuate experts. In that vein...
I produce for you a book written by a relevant expert
According to Wikipedia the author of that book, Staffan Lindeberg, is "M.D., Ph.D., (born 1950) is Associate Professor of Family Medicine at the Department of Medicine, University of Lund, Sweden. He is a practicing GP at St Lars Primary Health Care Center, Lund, Sweden."
I agree he's a health expert. I even agree he's more qualified to judge nutrition science than me. But shouldn't a nutrition scientist like Campbell be even more qualified to evaluate nutrition literature than a professor of Family Medicine?
He may be right, and Campbell completely wrong but I don't see a good way to figure this out for myself unless, say, someone can make an extremely good case that Campbell is either a rogue in nutrition science, or that nutrition science shouldn't be trusted. Getting to your next point...
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
Why wouldn't nutrition scientists studying nutrition come to a similar conclusion about how young, murky, and complicated nutrition is? Shouldn't they on average know this better than anyone and only make very careful and strongly supported recommendations?
If you can't trust nutrition scientists to judge the literature properly, why should you trust scientists outside of the field or layman attempting to dive into the field would be better?
There's a book called The China Study. It's written by the "Professor Emeritus of Nutritional Biochemistry at Cornell University, and his son Thomas M. Campbell II, a physician". 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.
When it was published in 2005 it recommended clearly crazy stuff: by minimizing or eliminating the consumption of animal based foods as well as refined/processed foods (e.g. adopt a "whole food plant-based diet"), you could greatly reduce your risk of diseases of affluence like heart disease, diabetes, some cancers, etc. The book follows his 60+ year career through cancer experiments on animals, conducting a pretty large epidemiological study (the China-Cornell-Oxford study), and then discusses some important clinical trials that support his recommendations. He also surveys some nutrition literature that corroborates his research.
Some other experts vocally support him; further, his recommendations don't seem to be a radical departure from either public health recommendations or prior research in the field. The FDA MyPlate, and also the UK's health initiatives ("5 fruits/vegetables a day"), as well as the Harvard School of Public Health's recommendations and others all seem to be moving in his general direction, although seemingly filtered by politics (e.g. telling Americans to stop eating meat entirely seems like political suicide, so baby steps in the direction seem more expedient; but I'm conjecturing this).
The book is widely dismissed as vegan propaganda, but the author says he's not advocating a vegan diet and in fact criticizes vegan diets as only minimally healthier than the "standard American diet". He also conducted experiments which subjected animals to carcinogens, which is not a very vegan thing to do. He does not admit to being vegan. He even observes that the evidence says restricting animal based calories to under 10% of total calories offers almost all of the health benefits as restricting them to 0%, but says as a practical matter this is much harder to stick to (e.g. you may only eat a 3mm slice of chocolate cake is much harder than simply saying no to chocolate cake). He also admits he had a bias when he entered the field of nutrition, but a bias in favor of attempting to justify the use of dairy to cure malnutrition (he came from a family of dairy farmers). He said when he discovered that his research did not support his dairy bias he abandoned his dairy bias (and would later shut down his diary farm).
Anyway, the China Study is widely criticized, but not by people in his field? 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.
(C is worthwhile, but this is a problem for public health authorities to worry about. I'm much more interested in what any sufficiently motivated individual can elect to do to maximize their health)
So, this is the part that I find most surprising. 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.
What should I believe? Here are things I've considered.
1. Science is crap. Don't believe expert predictions about the natural world.
2. No no, just nutrition science is crap. Don't believe any expert predictions about nutrition.
3. Nutrition science isn't crap, but the Campbells are rogue and the community of nutrition scientists have better things to do than debunk pop culture books.
4. Nutrition scientists **are** criticizing him in droves, I just don't come across them because I have confirmation bias blinders on.
5. "Nutrition scientist" is a made up discipline, and I've been tricked!
I'm more or less at a loss on how to make progress on these points. Am I missing something crucial?
What's the LW take on this? Why isn't this good enough to inform your dietary choices? 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?
EDIT: I would just like to thank everyone who responded. I've tried to discuss this in many forums, both IRL and on the internet and it's almost always a disaster unlike here on LW. Your measured, insightful responses are an enormous relief. You've given me a lot of food (ha!) for thought.
Your question is: after an airliner accident, how often do any of the next n flights following the same route also have an accident?
Guessing (2/3 confidence) lower than the base rate.
Close. If the accident is completely unexplained, as it often is immediately following an accident, shouldn't the risk be substantially higher immediately following the accident and then rapidly decay back to baseline as more information becomes available?
So. Inevitably after a plane crash a discussion comes up where someone may say that they're worried about flying now, and someone else pulls out the statistic that driving to the airport is more dangerous than flying. I think this reasoning is basically correct on the long-term, but not appropriate in the short-term.
Suppose it's the day after flight MH370 mysteriously disappeared. Information is extremely sketchy. You're about to get on a similar plane, operated by the same airliner, taking off from the same airport flying the same route. Should you get on the plane? That is, are you wrong to worry more than usual when we have no idea what happened to MH370? I would say no. The complete disappearance of flight MH370 without warning and without a trace the day before says **update your priors** at least for the short-term.
It's clear if you plan to live a reasonably frugal lifestyle working a normal job you can save up a substantial nest-egg in 10-20 years to float you indefinitely if you're only a little bit lucky, probably requiring a lot less luck than hoping you strike gold on a startup.
True. The way I see it, the benefit to that is the marginal increase in retirement safety. And the cost is the forgone opportunity of doing something important in those 10-20 years. What do you think of those trade offs? In particular, I'm currently thinking that there's already a really high chance that I can retire comfortably because of 1, 2 and 3.
Permit me to ramble a bit.
So, I think I have a bias against startups for getting rich. I think it might be reasonable.
I'll relate my personal experience as well as the experiences of three close friends. Around eight years ago, four of us each joined different startups. I quit mine about 3 1/2 years in. They've remained at theirs. What's the current status?
me: I've learned that my equity in my startup, which I took at a substantial discount to my salary, is now worth low six figures.
friend 1: his startup has almost been acquired but the deal sunk in due dilligence. Not in danger of going out of business but not exactly striking gold either. At least not yet.
friend 2: recently had his startup acquired and he received a low six figure bonus on the condition he stay another two years to ease the transition. It seems like he was cut out of the upside somehow.
friend 3: nothing close to an exit in sight; the company isn't failing, but it doesn't seem like it's going to strike gold either. It's slowly growing.
The low six figures of equity I (now) have might be seen as a positive, but 8 years on and I still can't sell it, and I had to take low pay and do a ton of work to get it. This is better than most startups, but still not a success.
In the meantime after I quit my startup I joined an established company and made a high-normal salary + bonuses and am way ahead of the rest of my friends on net worth (we all basically started at zero).
Two of my friends are only finally now making normal job salaries, but they're basically burned out at their respective companies and can't bring themselves to quit because they signed deals where their equity evaporates if they walk away. This is probably the largest danger to joining a startup: what if it drags on forever, and it seems like you could get your payday if you keep hanging on for six more months and this goes on for years and years? Do you think you could just walk away? I think this is loss aversion bias at work.
Should people work at startups? Absolutely: the experience is outstanding. You will learn a lot, the energy is amazing, and there are seldom better opportunities to feel that you're making a real difference in the world (at least for awhile). Should people work at startups to get rich? I couldn't recommend it. It's probably going to fail, but worse, it might nearly fail and stumble along for years never amounting to anything but tricking you into riding it for longer than you should. Even worse still, it might succeed and you might not have been ninja enough about your contract to ensure you get a fair deal.
I'm glad I worked at one startup, but I definitely couldn't have stomached working for, say, 5 startups in a row. The emotional rollercoaster of just one startup was enough.
(4) I work a normal-ish job, have a normal retirement plan, and save enough to retire at a normal age.
The point I want to make in this article is that 1, 2, 3 seem way more likely than 4. Which makes me think that long-term saving might not actually be such a good idea.
Are you sure? Take a look at http://firecalc.com/
You plug in your nest egg size and expected cost of living and it will trial it against historical market performance. That is, if you retired the day before the Great Depression and similar events, would your portfolio keep you alive long enough?
It's clear if you plan to live a reasonably frugal lifestyle working a normal job you can save up a substantial nest-egg in 10-20 years to float you indefinitely if you're only a little bit lucky, probably requiring a lot less luck than hoping you strike gold on a startup.
Are you sure there's no future utility? Doesn't resisting these useless but pleasurable activities deplete the ego? Doesn't depleted ego lead to bad decision-making?
For at least some of the stuff I do, yes I'm sure. You can easily reduce this ego-depletion argument to absurdity by supposing that foregoing every minor indulgence is ego-depleting and that you should never deny yourself. Even that there exists some activity B with higher (expected) future utility than activity A, but lower present utility, which we sometimes nevertheless forego in favour of higher immediate returns shows that we don't act to maximise future utility; you lose out on the difference in opportunity cost.
To suggest that such activities B don't exist, or that we never choose them, is to suggest that (at least some) human beings are entirely "subjectively rational", i.e. always make the choice they believe to yield optimal future benefit. If you know any such person see if you can gather up a few hair samples so we can clone him!
Alright, let's say I agree that in the space of all possible activities there exist some pleasurable activities that have zero future utility.
Couldn't we die at any minute? Given this, shouldn't we always do the pleasurable thing so long as there's no negative utility and no opportunity cost because there's a small chance it'll be the last thing we do?
Doesn't choosing the beautiful vacation that evaporates when it's over have the benefit that if we die in the middle of it, life was just that much more pleasant?
I guess I don't understand why someone would choose not to take the vacation.
What I mean is "this is what I think he intended".
Understood. In that case, I disagree on this point.
most of us choose to indulge in pleasures that have no future utility (and in some cases have negative future utility) all the time. We eat junk food, watch TV, waste time watching cat videos. Things that would not obviously be missed if they could not be got.
Are you sure there's no future utility? Doesn't resisting these useless but pleasurable activities deplete the ego? Doesn't depleted ego lead to bad decision-making?
This is not to say that every time a parole judges eat a brownie it's because they're trying to protect their ability to make sound decisions, merely that I don't agree that it's the same as taking a vacation that totally evaporates when it's over.
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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"?
Sorry, as gwillen assumes below, that's my actual position proviso nobody explains to me why nutrition science is hopelessly broken and/or Campbell should be ignored. Which is what I was hoping to learn by posting this.