LessWrong developer, rationalist since the Overcoming Bias days. Connoisseur of jargon.
jimrandomh(Jim Babcock)
Karma: 15,898
Our past beliefs affect what we pay attention to, how we prioritize our skepticism, and how we interpret ambiguous evidence. This can create belief basins, where there are multiple sets of beliefs that reinforce each other, appear internally consistent, and make it hard to see the other basins as valid possibilities. On the topic of nutrition, I seem to have found myself in a different basin. I’ve looked through every nonstandard lens I could find, repeatedly applied skepticism, and firmly committed to not make the same mistakes everyone else is making (as a priority on par with not making mistakes at all). I’ve arrived at a set of beliefs that, as far as I can tell, is internally consistent, reasonably compelling from the inside, and completely contrary to what most other people in our culture think.
This makes for a difficult writing project. When I try to argue nonstandard positions, many of the arguments are tendrils reaching into other nonstandard positions. I’ve finally managed to get into a post-every-day cadence; part of the key to that was accepting that sometimes those arguments will be dangling references. Hopefully after a month of this, the whole thing will cohere. If not, well, the fragments are pretty interesting too.
The most-common basin of nutrition theorizing centers on obesity, and on a particular theory of obesity which goes like this. Food, especially modern processed food, tastes good and is appealing. Some people, if they followed their urges, would eat too much or become obese, so they have to exert self control not to. Weight is a function of calorie intake and calorie expenditure (“calories in, calories out”), and expenditure is primarily a function of behavior. So if someone is trying to lose weight, and it isn’t working, then they must be having willpower failures and eating more than they intend, or exercising less than they intend.
I currently think there are quite a lot of things wrong with this model, but today, I’d like to focus on one in particular. It’s not the only or the most central objection, nor is it a particularly actionable model fragment. But it’s an issue that’s important to me in particular, and it’s one of the wedges that moved into a different belief basin.
I am not obese, and have never set out to lose weight. But sometimes, I have overwhelming cravings for sugar. I would not be able to resist these cravings without great willpower.
If I ever did successfully resist one of those cravings, I would probably die.
I don’t mean this figuratively, or in a heart-disease-years-later sort of way. I mean that if I get a powerful craving for sugar, and I don’t promptly eat something that has sugar in it, then this will be a life-threatening medical emergency. This is because I have type 1 diabetes, and craving sugar is a symptom of low blood sugar, aka hypoglycemia. What T1 diabetes means, basically, is that I have to micromanage my blood sugar using insulin. Eating carbohydrates raises blood sugar, insulin lowers it, these need to be matched pretty precisely, and the whole thing is somewhat error prone. Too much insulin and blood sugar falls below 70mg/dL, and I get the sugar craving. I’ve never been below 40mg/dL, but people who do become mentally impaired, then lose consciousness, then die.
Under the usual theory of obesity, craving sugar would mean that I had been hijacked by the superstimulus of processed food, and that willpower was my defense against this hijacking. But actually, in this case, the craving is a safety mechanism. Sugar craving is to dangerous hypoglycemia as thirst is to dehydration.
With that example in mind, I started thinking about the double-digit percentage of people who drop out of weight-loss studies. And the much-larger percentage of people who start weight loss diets, privately resolved to continue until they reach a target weight, and stop early. What would happen to them, in the counterfactual world where the diet was enforced perfectly from outside, and willpower wasn’t an issue? Whether they would lose weight, seems like very much the wrong question to ask.
I think they may be a negative correlation between short-term and long-term weight change on any given diet, causing them to pick in a way that’s actually worse than random. I’m planning a future post about this. I’m not super confident in this theory, but the core of it is that “small deficit every day, counterbalanced by occasional large surplus” is a pattern that would signal food-insecurity in the EEA. Then some mechanism (though I don’t know what that mechanism would be) by which the body remembers that happened, and responds by targeting a higher weight after return to ad libitum.
Yesterday, I wrote a post about the Regression to the Mean Diet. The biggest impact knowing about the Regression to the Mean Diet has had for me is on my interpretations of studies, where it’s a lens that reveals what would otherwise be the best studies to be mostly useless, and of anecdotes, where it makes me heavily discount claims about a new diet working unless I’ve gotten to ask a lot of questions about the old diet, too. But there’s one other implication, which I left out of the original post, because it’s kind of unfortunate and is a little difficult to talk about.
I’m not interested in nutrition because I care about weight, or body aesthetics, or athletic performance. I care about nutrition because I believe it has a very large, very underappreciated impact on individual productivity. Low quality diets make people tired and depressed, so they don’t get anything done.
The Regression to the Mean Diet predicts that if you reroll the eating habits of someone whose diet-related health is unusually bad, then their new diet will probably be an improvement. This has a converse: if you reroll the eating habits of someone whose diet-related health is good, especially if that person is a peak performer in some way, then their new diet will be worse.
Under this model, one of the most destructive things you could do would be to identify top performers in important areas, people in good health with no nutritional problems, and convince them they need to change their diet.
Which brings me to vegan outreach within the Effective Altruism movement.
I don’t think an animal’s suffering is anywhere close to as bad as a similar amount of suffering in a human, but I do think it matters, and that this makes modern factory farming quite bad. While I have qualms about the quality of vegan diets in practice, I think that if you convince an average person from the general public to switch from an omnivorous diet they haven’t thought much about to a vegan diet with any thought at all put into it, this will on average be an improvement. I think externally-facing vegan outreach is good, and while I wouldn’t prioritize it over AI alignment or anti-aging research, I am in favor of it.
But inward-facing vegan outreach scares me. Because EA is in fact seeking out top performers in important areas, and introducing them to its memes. Under the current social equilibrium, those people feel some pressure to reduce their meat consumption, but not many make large dietary changes; most of the people who are vegetarian or vegan within EA where vegetarian or vegan beforehand. It’s easy to imagine a different equilibrium, in which the majority of omnivores who get involved in EA go vegan.
I worry that in that world, what would be the top-percentile people are no longer top percentile, and no one notices the absence or makes the connection.
The altitude correlation would seem to suggest drinking water in particular as a culprit, and suggests a simple and straightforward study that would settle the question once and for all: randomize a group of households to either receive reverse osmosis filters on their taps, or not, then track whether the people in those households become obese.
I checked whether this study has been performed, and as far as I can tell, it hasn’t. There have been studies that randomly installed reverse osmosis filters, but they were checking for something else and didn’t track peoples’ weight.
I have a dietary intervention that I am confident is a good first-line treatment for nearly any severe-enough diet-related health problem. That particularly includes obesity and metabolic syndrome, but also most micronutrient deficiencies, and even mysterious undiagnosed problems, which it can solve without even needing to figure out what they are. I also think it’s worth a try for many cases of depression. It has a very sound theoretical basis. It’s never studied directly, but many studies test it, usually with positive results.
It’s very simple. First, you characterize your current diet: write down what foods you’re eating, the patterns of when you eat them, and so on. Then, you do something as different as possible from what you wrote down. I call it the Regression to the Mean Diet.
Regression to the mean is the effect where, if you have something that’s partially random and you reroll it, the reroll will tend to be closer to average than the original value. For example, if you take the bottom scorers on a test and have them retake the test, they’ll do better on average (because the bottom-scorers as a group are disproportionately peopple who were having a bad day when they took the test). Analogously, if your health is very bad on an axis that seems diet-related, and you reroll your entire selection of foods, then this will (on average) be an improvement.
The Regression the Mean diet is, basically, betting on the idea that there’s something wrong with your current diet, and that you can fix it by changing everything, without needing to figure out what the original problem was. That could be a deficiency, or a food sensitivity, or something in the time-dynamics of digestion, or a hundred other things, many of which you won’t have even had as hypotheses.
I do recommend this to people, if it looks like their health sucks in nonspecific ways that are hard to pin down. One of the biggest-change diets is a ketogenic diet (high fat, near-zero carbohydrates), since it’s incompatible with most foods.
But the main reason I think about the Regression to the Mean Diet is that it ruins so many scientific studies.
There are two main kinds of studies, in nutrition science. The first is observational: you send a bunch of people questionnaires about what they eat, and what their health is like, and you data-mine the results. This has a bunch of issues, both subtle and obvious, so the gold standard you want is randomized controlled trials, where people sign up to eat a diet that experimenters choose for them.
The people who sign up for diet RCTs are obese and have metabolic syndrome. They are exactly the sort of people you would expect to benefit from the Regression to the Mean diet. And this model, alone, is sufficient to predict the result of most diet RCTs.
This is really unfortunate if you’re trying to extract gears-level understanding from these studies. Or if you’re trying to optimize past 50th-percentile diet-related health. Or if rerolling has already failed to work for you a couple times.
One difficult thing that keeps coming up, in nutrition modeling, is the gut microbiome. People present hypotheses like: soluble fiber is good, because gut bacteria eat it, and then do other good things. Or: fermented foods are good, because they contain bacteria that will displace and diversify the preexisting bacteria, which might be bad. Or, obesity is caused by a bad gut microbiome, so fecal matter transplants might help. But there’s a really unfortunate issue with these theories. The problem with gut microbiome-based explanations, is that the gut microbiome can explain almost anything.
I don’t mean this in the usual pejorative sense, where an overly-vague theory can be twisted by epicycles into fitting any data. I mean it in a more literal sense: different people have different species of microorganisms in their guts, these species can react to things we eat in important ways, these interactions may vary across wide swathes of conceptual space, and we have little to no visibility into which species are present where. There’s nothing keeping them consistent between people, or within one person across long spans of time, or within one person across changes in dietary pattern.
Phrased slightly differently: the main effect of the gut microbiome is to drive interpersonal variation.
I bring this up not because I have something especially insightful to say about gut microbiomes, but because this makes a good lens for a meta-level issue. I’ve been studying nutrition, at varying levels of seriousness, for a long time; now that I’ve accumulated a lot of unusual beliefs, and gotten into a writing groove, I think it’s worth explaining the generator behind my thinking.
The dominant paradigm of nutrition science is to try to make a food-goodness classifiers: define some reference class of foods and say “these ones are good”, and some other reference class of foods and say “these ones are bad”. People want a direct answer to the question of what they should eat, rather than gears-level models with which they might discover what they should eat.
The food-goodness-classifier paradigm cannot, and will not ever, figure out how people should relate to their gut microbiomes. Nor will this paradigm yield insights into how to handle genetic variation, or medical conditions that interact with metabolism like T1DM. I used to think the food-goodness-classifier paradigm would at least contain an answer to obesity, somewhere. Today, I think it’s failed, and will never succeed, at obesity too.
My search space for nutrition insights is: Everything except the food-goodness-classifier paradigm.
And so I find myself with strong opinions about the time dynamics of digestion. A few alternate stories about the environment of evolutionary adaptation, where food is hazardous rather than scarce, or scarce in unusually specific ways. A map of the body’s multiple energy-storage mechanisms, where the central mystery is why there rather than why so much. Beliefs about how, if you found yourself in an alien biome with randomly rewired taste buds, you would figure out a healthy diet from scratch. More methodological objections to major studies than you can shake a stick at.
This does sometimes cash out into food-goodness-classifier opinions, and I did have to get through a lot of those opinions to get there. Sometimes, these are weird reversals of standard advice, with deep models behind them; eg, I am generally pro-salt and pro-fat, for reasons I’ll get into in a later post. Other times I just agree with what everyone else thinks, and don’t really bring it up, because “yo, don’t get scurvy” isn’t insightful, and I’m not trying to be exhaustive in that way.
I’m not trying to create an optimal diet. These posts are not leading up to a meal plan, and if you’re just trying to figure out what to eat, you are not my intended audience. Instead, my goal is to break nutrition science out of its rut, and lay groundwork for progress.
I think the negative epistemic effects of misinformation are much more important than the motivational effects; and that most of the negative epistemic effect comes not from taking the misinformation on its own terms, but from dragging down the conversation so that relevant truths (eg: nuclear power is good, recycling is probably net negative) get lost in the noise.
One of the most common, least questioned pieces of dietary advice is the Variety Hypothesis: that a more widely varied diet is better than a less varied diet. I think that this is false; most people’s diets are on the margin too varied.
There’s a low amount of variety necessary to ensure all nutrients are represented, after which adding more dietary variety is mostly negative. Institutional sources consistently overstate the importance of a varied diet, because this prevents failures of dietary advice from being too legible; if you tell someone to eat a varied diet, they can’t blame you if they’re diagnosed with a deficiency.
There are two reasons to be wary of variety. The first is that the more different foods you have, the less optimization you can put into each one. A top-50 list of best foods is going to be less good, on average, than a top-20 list. The second reason is that food cravings are learned, and excessive variety interferes with learning.
People have something in their minds, sometimes consciously accessible and sometimes not, which learns to distinguish subtly different variations of hunger, and learns to match those variations to specific foods which alleviate those specific hungers. This is how people are able to crave protein when they need protein, salt when they need salt, and so on.
If every meal you eat tastes different, you can’t instinctively learn the mapping between foods and nutrition, and can’t predict which foods will hit the spot. If you need and crave protein, and wind up eating something that doesn’t have protein in it, that’s bad.
If the dominant flavor of a food is spice, then as far as your sense of taste is concerned, its nutritional content is a mystery. If it’s a spice that imitates a nutrient, like MSG or aspartame, then instead of a mystery it’s a lie. Learning how to crave correctly is much harder now than it was in the past. This is further exacerbated by eating quickly, so that you don’t get the experience of feeling a food’s effects and seeing that food on your plate at the same time.
I’m not sure how to empirically measure what the optimum amount of variety is, but I notice I have builtin instincts which seem to seek it when I have fewer than 10 or so different meal-types in my habits, and to forget/discard meal-types when I have more than that; if this parameter is evolved, this seems like a reasonable guess for how varied diets should be.
Standard Advice about nutrition puts a lot of emphasis on fruits and vegetables. Now, “vegetable” is a pretty terribly overbroad category, and “fruit or vegetable” is even more so, but put that aside for a moment. In observational studies, eating more fruits and vegetables correlates with good health outcomes. This is usually explained in terms of micronutrients. But I think there’s a simpler explanation.
People instinctively seek nutrients—water, calories, protein, and other things—in something that approximates a priority ordering. You can think of it as a hierarchy of needs; it wouldn’t make sense to eat lettuce while you’re starved for protein, or beans while you’re dehydrated, and people’s cravings reflect that.
I have started calling this Maslow’s Hierarchy of Foods.
Vegetables do not rank highly in this priority ordering, so eating salads is pretty good evidence that all of someone’s higher-priority nutritional needs are met. I believe this explains most of the claimed health benefits from eating vegetables, as seen in observational studies.
Conversely, sugar is the fastest way to get calories (all other calorie sources have a longer digestion-delay), so craving sugar is evidence that someone has *not* satisfied their high-priority nutritional needs. Someone who eats a lot of candy bars is likely to be undereating in general, and not getting enough protein/fat/salt/micronutrients. I believe this explains most of the claimed health harms from eating sugar, as seen in observational studies.
A lot of people seem to think of cravings as a negative force, shifting people away from whatever optimal diet they would have chosen and towards superstimulus junk food. I think that’s a huge mistake, and that understanding how to eat well, and figuring out what’s going wrong in the modern food environment, requires making use of the information our food-related instincts provide.
COVID variants have mutated in the direction of faster spread and less immunity, as expected. They also seem to be mutating to higher disease severity, which was not expected. Why would that be, and should we expect this to continue?
My current theory is that the reason variants are more severe is because there’s evolutionary pressure on a common factor that affects both severity and secondary attack rate, and that factor is viral replication rate.
In the initial stage of an infection, the number of virus-copies inside someone grows exponentially. If the spike protein mutates to get slightly more reliable, then the doubling time of that growth shrinks. Result: Increased viral shedding, decreased minimum infectious dose, increased severity.
I hypothesize that we’re used to respiratory diseases evolving towards lower severity because, first, they’ve already maxed out this particular axis, and second, because they rely on people walking around in public while symptomatic, which they won’t do if the disease is too severe.
This retrodicts that data pretty well, but I’m still really unsure whether severity in the future is going to rise or fall. One one hand: there’s probably still room left to increase replication rate further, and the people-walking-around-if-mild transmission method isn’t going to come back. On the other hand, COVID might reach (or already be in) a local optimum with respect to spike-protein efficiency, in which case selection for immune-evasion will mean evolving away from the most-efficient version.
Cutting away all the word games, this paper appears to claim that if an agent is intelligent in a way that isn’t limited to some narrow part of the world, then it can’t stably have a narrow goal, because reasoning about its goals will destabilize them. This is incorrect. I think AIXI-tl is a straightforward counterexample.
(AIXI-tl is an AI that is mathematically simple to describe, but which can’t be instantiated in this universe because it uses too much computation. Because it is mathematically simple, its properties are easy to reason about. It is unambiguously superintelligent, and does not exhibit the unstable-goal behavior you predict.)
Most philosophical analyses of human values feature a split-and-linearly-aggregate step. Eg:
Value is the sum (or average) of a person-specific preference function applied to each person
A person’s happiness is the sum of their momentary happiness for each moment they’re alive.
The goodness of an uncertain future is the probability-weighted sum of the goodness of concrete futures.
If you value multiple orthogonal things, your preferences are the weighted sum of a set of functions that each capture one of those values independently.
I currently think that this is not how human values work, and that many philosophical paradoxes relating to human values trace back to a split-and-linearly-aggregate step like this.
Probably some stray keystrokes into autocomplete? You can see who applied the tag on the tag history page and can un-apply the tag by downvoting the tag’s relevance score in the list on the tag page. (This does not affect anyone’s karma.)
One of the reasons I worry about cybersecurity, and the sorry state it’s in, is that it provides an easy path for human-level and even infrahuman-level AIs to acquire additional computation. In some plausible worlds, this turns a manageable infrahuman AI into an unmanageable superintelligence, when the creator’s decision would have been not to launch.
Unlike solving protein-design and constructing nanobots, this is something definitely within reach of human-level intelligence; many people have done it for ordinary criminal purposes, like mining cryptocurrency.
Current cybersecurity research incentives don’t seem quite right for getting people to mitigate this risk. If I were trying to stop an AI from taking over the internet and using the extra hardware to make itself superintelligent, I would worry a lot less about protecting user data, phones and whatnot, and worry a lot more about protecting software developer workstations in particular.
I wouldn’t expect if(f) to be linguistically successful; it’s weird in a not-quite-a-word way that means it can’t ever become a regular vocabulary item.
I think this is correct as a final analysis, but ineffective as a cognitive procedure. People who start by trying to identify villains tend to land on landlords-in-general, with charging-high-rent as the significant act, rather than a small subset of mostly non-landlord homeowners, with protesting against construction as the significant act.
But they did miss something key!
“Eff” is the pronounciation of the letter f, so iff becomes if-f becomes if-eff. It might be more intuitive with a dash, but also it’s less like a word. I’ll edit in an explanation of the etymology; I thought it was more intuitive than it actually was.
Does it solve your use case if I edit prev/next links into all of them?
(For now I’m focused on keeping a writing cadence going, and not thinking too much about publication format. There’s a decent chance that, after I’ve depleted the backlog of unpublished ideas I’ve had, I’ll do a second pass of some sort and make it more polished; but I don’t think that’s certain enough that you should count on it.)