diet

All posts tagged diet

[Warning: this post contains lots of guesses based on weak evidence. I’d be surprised if I got more than 80% of it right.]

I’ve long acted as if a good diet is fairly important, and I’ve gathered lots of relevant evidence. But until recently I classified that evidence into many small topics related to specific nutrients and health problems, and never organized those ideas into an overall assessment of how important a good diet is.

Comments by Jim Babcock prompted me to investigate a broader overview.

This post will mainly focus on evaluating the importance of nutrition for adults in wealthy nations, then will summarize my guesses about how to achieve a good diet.

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Book review: The Plant Paradox, by Steven R. Gundry.

This book describes a good diet, which Gundry seems to have put together by combining ideas from other competent nutritionists, testing many variations on himself and his patients, and keeping the components that showed the best results.

Unfortunately, his rhetoric is designed to convince us that he’s got brilliant, revolutionary theories. That rhetoric bears little resemblance to careful reasoning. It seems more likely that he tried a bunch of arguments on his patients, and kept the ones that more effectively scared them into following his diet.

His puns are mightier than his scalpel (“No More Mr. Knife Guy”).

I first noticed Gundry via the ApoE4 website, at about the time I gave up hoping that I could eat coconut fat without raising my cholesterol. I saw that Gundry recommended no coconut fat for my genotype, but liked coconut fat for others. That led me to think: here’s a paleo-friendly nutritionist who knows more than average.

Then I switched for 5 or 6 weeks to a diet more in line with his Apoe4 advice [1], and was surprised at how much more my cholesterol levels dropped than I expected. I only have modest evidence suggesting that that dietary change was the main reason for the cholesterol drop, but it’s still a bit of evidence that Gundry knows something valuable that I would have otherwise have overlooked.
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No, this isn’t about cutlery.

I’m proposing to fork science in the sense that Bitcoin was forked, into an adversarial science and a crowdsourced science.

As with Bitcoin, I have no expectation that the two branches will be equal.

These ideas could apply to most fields of science, but some fields need change more than others. P-values and p-hacking controversy are signs that a field needs change. Fields that don’t care much about p-values don’t need as much change, e.g. physics and computer science. I’ll focus mainly on medicine and psychology, and leave aside the harder-to-improve social sciences.

What do we mean by the word Science?

The term “science” has a range of meanings.

One extreme focuses on “perform experiments in order to test hypotheses”, as in The Scientist In The Crib. I’ll call this the personal knowledge version of science.

A different extreme includes formal institutions such as peer review, RCTs, etc. I’ll call this the authoritative knowledge version of science.

Both of these meanings of the word science are floating around, with little effort to distinguish them [1]. I suspect that promotes confusion about what standards to apply to scientific claims. And I’m concerned that people will use the high status of authoritative science to encourage us to ignore knowledge that doesn’t fit within its paradigm.

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Book review: Feeding Everyone No Matter What: Managing Food Security After Global Catastrophe, by David Denkenberger and Joshua M. Pearce.

I have very mixed feelings about this book.

It discusses some moderately unlikely risks – scenarios where most crops fail worldwide for several years, due to inadequate sunlight.

It’s hard to feel emotionally satisfied about a tolerable but uncomfortable response to disasters, when ideally we’d prevent those disasters in the first place. And the disasters seem sufficiently improbable that I don’t feel comfortable thinking frequently about them. But we don’t yet have a foolproof way of preventing catastrophic climate changes, and there are things we can do to survive them. So logic tells me that we ought to devote a few resources to preparing.

The authors sketch a set of strategies which could conceivably ensure that nobody starves (Wikipedia has a good summary). There might even be a bit of room for mistakes, but not much.

The book focuses on the technical problems, with the hope that others will solve the political problems. This makes some sense, as the feasibility of various political solutions is very different if the best political strategy saves 95% of people than if it saves 30%.

It’s a bit disturbing that this seems to be the most expert analysis available for these scenarios – the authors appear fairly competent, but seem to have done less research than I expect from a technical book. They may have made the right choice to publish early, in order to attract more support. I’m mainly disturbed by what the lack of expertise says about societal competence.

The book leaves me with lots of uncertainty about how hard it is to improve on the meager preparations that have been done so far.

For example, I expect there are a moderate number of people who know something about rapidly scaling up mushroom production. Are they already capable of handling the needed changes? Or are drastically different preparations needed? It’s hard for me to tell without developing significant expertise in growing mushrooms.

There’s probably an urgent need for a bit more preparation for extracting nutrition from ordinary leaves. In particular, I expect it to matter what kinds of leaves to use. The book mostly talks of leaves from trees, but careless people in my area might include poison hemlock leaves, with disastrous results. A small amount of advance preparation should be able to cause large reductions in this kind of mistake.

Another simple preparation that’s needed is a better awareness of where to look in a crisis. The news media in particular ought to be able to quickly find this kind of information even when they’re overwhelmed with problems.

I’m guessing that a few hundred thousand dollars of additional effort in this area would have high expected value, with strongly diminishing returns after that. I’ve donated a small amount to ALLFED, and I encourage you to donate a little bit as well.

I got interested in trying ashwagandha due to The End of Alzheimer’s. That book also caused me to wonder whether I should optimize my thyroid hormone levels. And one of the many features of ashwagandha is that it improves thyroid levels, at least in hypothyroid people – I found conflicting reports about what it does to hyperthyroid people.

I had plenty of evidence that my thyroid levels were lower than optimal, e.g. TSH levels measured at 2.58 in 2012, 4.69 in 2013, and 4.09 this fall [1]. And since starting alternate day calorie restriction, I saw increasing hypothyroid symptoms: on calorie restriction days my feet felt much colder around bedtime, my pulse probably slowed a bit, my body burned fewer calories, and I got vague impressions of having less energy. Presumably my body was lowering my thyroid levels to keep my weight from dropping.

I researched the standard treatments for hypothyroidism, but was discouraged by the extent of disagreement among doctors about the wisdom of treating hypothyroidism when it’s as mild as mine was. It seems like mainstream medical opinion says the risks slightly outweigh the rewards, and a sizable minority of doctors, relying on more subjective evidence, say the rewards are large, and don’t say much about the risks. Plus, the evidence for optimal thyroid levels protecting against Alzheimer’s seems to come mainly from correlations that are seen only in women.

Also, the standard treatments for hypothyroidism require a prescription (probably for somewhat good reasons), which may have deterred me by more than a rational amount.

So I decided to procrastinate any attempt to optimize my thyroid hormones, and since I planned to try ashwagandha and DHEA for other reasons, I hoped to get some evidence from the small increases to thyroid hormones that I expected from those two supplements.

I decided to try ashwagandha first, due mainly to the large number of problems it may improve – anxiety, inflammation, stress, telomeres, cholesterol, etc.
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Book review: The End of Alzheimer’s, by Dale E. Bredesen.

Alzheimer’s can be at least postponed for years in most people, and maybe fully cured.

The main catches: It only works if started early enough (and Bredesen only has crude guesses about what’s early enough), the evidence is less rigorous than I’d like, and it’s not a medical treatment, it’s a quantified self approach on steroids ketones.

My guess is that the book is roughly 70% correct. If so, that’s an enormous advance.
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Book review: Seasteading, by Joe Quirk, with Patri Friedman.

Seasteading is an interesting idea. Alas, Quirk’s approach is not quirky enough to do justice to the unusual advantages of seasteading.

The book’s style is too much like a newspaper. Rather than focus on the main advantages of seasteading, it focuses on the concerns of the average person, and on how seasteading might affect them. It quotes interesting people extensively, while being vague about whether the authors are just reporting that those people have ideas, or whether the authors have checked that the ideas are correct. Many of the ideas seem rather fishy.

I suspect that seasteading’s biggest need now is businessmen and/or VCs who can start cruise-ship-sized projects. Yet the book seems aimed more at creating broad, shallow support among ordinary readers than it is at inspiring competent entrepreneurs.
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Book review: The Hungry Brain: Outsmarting the Instincts That Make Us Overeat, by Stephan Guyenet.

Researchers who studied obesity in rats used to have trouble coaxing their rats to overeat. The obvious approaches (a high fat diet, or a high sugar diet) were annoyingly slow. Then they stumbled on the approach of feeding human junk food to the rats, and made much faster progress.

What makes something “junk food”? The best parts of this book help to answer this, although some ambiguity remains. It mostly boils down to palatability (is it yummier than what our ancestors evolved to expect? If so, it’s somewhat addictive) and caloric density.

Presumably designers of popular snack foods have more sophisticated explanations of what makes people obese, since that’s apparently identical to what they’re paid to optimize (with maybe a few exceptions, such as snacks that are marketed as healthy or ethical). Yet researchers who officially study obesity seem reluctant to learn from snack food experts. (Because they’re the enemy? Because they’re low status? Because they work for evil corporations? Your guess is likely as good as mine.)

Guyenet provides fairly convincing evidence that it’s simple to achieve a healthy weight while feeling full. (E.g. the 20 potatoes a day diet). To the extent that we need willpower, it’s to avoid buying convenient/addictive food, and to avoid restaurants.

My experience is that I need a moderate amount of willpower to follow Guyenet’s diet ideas, and that it would require large amount of willpower if I attended many social events involving food. But for full control over my weight, it seemed like I needed to supplement a decent diet with some form of intermittent fasting (e.g. alternate day calorie restriction); Guyenet says little about that.

Guyenet’s practical advice boils down to a few simple rules: eat whole foods that resemble what our ancestors ate; don’t have other “food” anywhere that you can quickly grab it; sleep well; exercise; avoid stress. That’s sufficiently similar to advice I’ve heard before that I’m confident The Hungry Brain won’t revolutionize many people’s understanding of obesity. But it’s got a pretty good ratio of wisdom to questionable advice, and I’m unaware of reasons to expect much more than that.

Guyenet talks a lot about neuroscience. That would make sense if readers wanted to learn how to fix obesity via brain surgery. The book suggests that, in the absence of ethical constraints, it might be relatively easy to cure obesity by brain surgery. Yet I doubt such a solution would become popular, even given optimistic assumptions about safety.

An alternate explanation is that Guyenet is showing off his knowledge of brains, in order to show that he’s smart enough to have trustworthy beliefs about diets. But that effect is likely small, due to competition among diet-mongers for comparable displays of smartness.

Or maybe he’s trying to combat dualism, in order to ridicule the “just use willpower” approach to diet? Whatever the reason is, the focus on neuroscience implies something unimpressive about the target audience.

You should read this book if you eat a fairly healthy diet but are still overweight. Otherwise, read Guyenet’s blog instead, for a wider variety of health advice.

Book review: Aging is a Group-Selected Adaptation: Theory, Evidence, and Medical Implications, by Joshua Mitteldorf.

This provocative book argues that our genes program us to age because aging provided important benefits.

I’ll refer here to antagonistic pleiotropy (AP) and programmed aging (PA) as the two serious contending hypotheses of aging. (Mutation accumulation used to be a leading hypothesis, but it seems discredited now, due to the number of age-related deaths seen in a typical species, and due to evidence that aging is promoted by some ancient genes).

Here’s a dumbed down version of the debate:
<theorist>: Hamilton proved that all conceivable organisms age due to AP and/or mutation accumulation.
<critic>: But the PA theories better predict how many die from aging, the effects of telomeres, calorie restriction, etc. Also, here’s some organisms with zero or negative aging …
<theorist>: A few anomalies aren’t enough to overturn a well-established theory. The well-known PA theories are obviously wrong because selfish genes would outbreed the PA genes.
<critic>: Here are some new versions which might explain how aging could enhance a species’ fitness …
<theorist>: I’ve read enough bad group-selection theories that I’m not going to waste my time with more of them.

That kind of reaction from theorists might make sense if AP was well established. But AP seems to have been well established only in the Darwinian sense of being firmly entrenched in scientists’ minds. It got entrenched mainly by being the least wrong of a flawed set of theories, combined with some poor communication between theorists and naturalists. Wikipedia has a surprisingly good[1] page on the evolution of aging that says:

Antagonistic pleiotropy is a prevailing theory today, but this is largely by default, and not because the theory has been well verified.

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