Change my mind: Veganism entails trade-offs, and health is one of the axes


To me, it is obvious that veganism introduces challenges to most people. Solving the challenges is possible for most but not all people, and often requires trade-offs that may or may not be worth it.  I’ve seen effective altruist vegan advocates deny outright that trade-offs exist, or more often imply it while making technically true statements. This got to the point that a generation of EAs went vegan without health research, some of whom are already paying health costs for it, and I tentatively believe it’s harming animals as well. 

Discussions about the challenges of veganism and ensuing trade-offs tend to go poorly, but I think it’s too important to ignore. I’ve created this post so I can lay out my views as legibly as possible, and invite people to present evidence I’m wrong. 

One reason discussions about this tend to go so poorly is that the topic is so deeply emotionally and morally charged. Actually, it’s worse than that: it’s deeply emotionally and morally charged for one side in a conversation, and often a vague irritant to the other. Having your deepest moral convictions treated as an annoyance to others is an awful feeling, maybe worse than them having opposing but strong feelings. So I want to be clear that I respect both the belief that animals can suffer and the work advocates put into reducing that suffering. I don’t prioritize it as highly as you do, but I am glad you are doing (parts of) it.

But it’s entirely possible for it to be simultaneously true that animal suffering is morally relevant, and veganism has trade-offs for most people. You can argue that the trade-offs don’t matter, that no cost would justify the consumption of animals, and I have a section discussing that, but even that wouldn’t mean the trade-offs don’t exist. 

This post covers a lot of ground, and is targeted at a fairly small audience. If you already agree with me I expect you can skip most of this, maybe check out the comments if you want the counter-evidence. I have a section addressing potential counter-arguments, and probably most people don’t need to read my response to arguments they didn’t plan on making. Because I expect modular reading, some pieces of information show up in more than one section. Anyone reading the piece end to end has my apologies for that. 

However, I expect the best arguments to come from people who have read the entire thing, and at a minimum the “my cruxes” and “evidence I’m looking for” sections. I also ask you to check the preemptive response section for your argument, and engage with my response if it relates to your point. I realize that’s a long read, but I’ve spent hundreds of hours on this, including providing nutritional services to veg*ns directly, so I feel like this is a reasonable request. 

My cruxes

Below are all of the cruxes I could identify for my conclusion that veganism has trade-offs, and they include health:

  • People are extremely variable. This includes variation in digestion, tastes, time, money, cooking ability… 
  • Most people’s optimal diet includes small amounts of animal products, but people eat sub-optimally for lots of reasons and that’s their right. Averting animal suffering is a better reason to eat suboptimally than most. 
  • Average vegans and omnivores vary in multiple ways, so it’s complicated to compare diets. I think the relevant comparison healthwise is “the same person, eating vegan or omnivore” or “veganism vs. omnivorism, holding all trade-offs but one constant”.
  • For most omnivores who grew up in an omnivorous culture, going vegan requires a sacrifice in at least one of: cost, taste (including variety), health, time/effort.
    • This is a mix of capital investments and ongoing costs – you may need to learn a bunch of new recipes, but if they work for you that’s a one time cost.
    • Arguments often get bogged down around the fact that people rarely need to sacrifice on all fronts at once. There are cheap ways for (most) people to eat vegan, but they either take effort and knowledge, or they’re bad for you (Oreos are vegan). There are vegan ways for most people to be close to nutritionally optimal, but they require a lot of planning or dietary monotony.
    • Some of the financial advantage for omnivores is due to meat subsidies that make meat artificially cheap, but not all of it, and I don’t know how that compares to grain subsidies.
  • There are vegan sources of every nutrient (including B12, if you include fortified products). There may even be dense sources in every or almost every nutrient. But there isn’t a satisfying plant product that is as rich in as many things as meat, dairy, and especially eggs. Every “what about X?” has an answer, but if you add up all the foods you would need to meet every need, for people who aren’t gifted at digestion, it’s far too many calories and still fairly restrictive.
    • “Satisfying” matters. There are vegan protein shakes and cereals containing ~everything, but in practice most people don’t seem to find these satisfying.
    • There isn’t a rich vegan source of every vitamin for every person. If there are three vegan sources and you’re allergic to all of them, you need animal products.
    • The gap between veganism and omnivorism is shrinking over time, as fortified fake meats and fake milks get better and cheaper. But these aren’t a cure-all.
      • Some people don’t process the fortified micronutrients as well as they process meat (and vice-versa, but that’s irrelevant on an individual level).
      • Avoiding processed foods or just not liking them is pretty common, especially among the kind of people who become vegan. 
      • Brands vary pretty widely, so you still need to know enough to pick the right fortified foods.
      • Fake meats are quite expensive, although less so every year.
        • I want to give the people behind fake meat a lot of credit. Making meat easier to give up was a good strategy for animal protection advocates.
  • Veganism isn’t weird for having these trade-offs. Every diet has trade-offs. I can name many diets I rank as having worse average trade-offs than veganism or a lower ceiling on health.
    • Carnivore diet, any monotrophic diet, ultralow calorie diets under most circumstances, “breathetarian”, liquid diets under most circumstances, most things with “cleanse” or “detox” in the name, raw foodism…
    • And even then, several of these have someone for whom they’re the best option.
  • The trade-offs vary widely by person. Some people have the digestive ability and palate of a goat and will be basically fine no matter what. Some people are already eating monotonous, highly planned diets and removing animal products doesn’t make it any harder. Some people are already struggling to feed themselves on an omnivore diet, and have nothing to replace meat if you take it away.
    • Vegan athletes are often held up as proof veganism can be healthy, with the implication that feeding athletes is hard mode so if it works for them it must work for everyone. But being a serious athlete requires a lot of the same trade-offs as veganism: you’re already planning diets meticulously, optimized for health over taste, with little variety, and taking a lot of supplements. If there are plant foods that work for you, swapping them in may be barely a sacrifice. Also, athletes have a larger calorie budget to work with.
  • Lots of people switch to vegan diets and see immediate health improvements.
    • Some improve because veganism is genuinely their optimal diet.
    • Others improve because even though their hypothetical optimal diet includes meat, the omnivore diet they were actually eating was bad for them and removing meat entirely is easier than eating good forms in moderation.
    • Others improve because they are putting more effort into their vegan diet, and they would be doing even better if they put that much effort into their omnivore diet.
    • Others see short-term improvement because animal products have both good points and bad points, and for some people the bad parts decay faster than the good parts. If your cholesterol goes down in a month and your B12 takes years to become a problem, it is simultaneously true that going vegan produced an immediate improvement, and that it will take a health toll.
  • Vegetarianism is nutritionally much closer to omnivorism than it is to veganism.
  • There exist large clusters of vegans who do not talk about nutrition and are operating naively. As in, no research into nutrition, no supplements, no testing, no conscious thought applied to their diet.
    • One of these clusters is young effective altruists whose top priority is not animal welfare (but nonetheless feel compelled to go vegan). 

Those are my premises. Below are a few conclusions I draw from them.  I originally didn’t plan on including a conclusion, but an early reader suggested my conclusions were milder than they expected and it might be good to share them. So: 

  • People recruiting for veganism should take care to onboard people in a responsible way. This could be as simple as referring people to frequently enough that they actually use it.
    • Recruiting means both organized efforts and informal encouragement of friends. 
  • Diet issues are a live hypothesis suggested to vegans with health problems, especially vague, diagnosis-resistant ones.
    • This one isn’t vegan specific, although I do think it’s more relevant to them.
  • False claims about vegan nutrition should be proactively rejected by the vegan community, in both formal and informal settings, including implicit claims. This includes:
    • Explicit or implicit claims veganism is healthy for everyone, and that there is no one for whom it is not healthy.
    • Explicit or implicit claims veganism doesn’t involve trade-offs for many people. 
    • Motte and baileys of “there is nothing magic about animal products, we can use technology to perfectly replace them” and “animal products have already been perfectly replaced and rendered unnecessary”.

My evidence

One is first principles. Animal products are incredibly nutrient dense. You can get a bit of all known nutrients from plants and fortified products, and you can find a vegan food that’s at least pretty good for every nutrient, but getting enough of all of them is a serious logic puzzle unless you have good genes. Short of medical issues it can be done, but for most people it will take some combination of more money, more planning, more work, and less joy from food. 

“Short of medical issues” is burying the lede. Food allergies and digestion issues mean lots of people struggle to feed themselves even with animal products; giving up a valuable chunk of their remaining options comes at a huge cost.

[Of course some people have issues such that animal products are bad for them and giving them up is an improvement. Those raise veganism’s average health score but don’t cancel out the people who would suffer]

More empirically, there is this study from Faunalytics, which found 29% of ex-vegans and ex-vegetarians in their sample had nutritional issues, and 80% got better within three months of quitting. Their recorded attrition rate was 84%, so if you assume no current veg*ns have issues that implies a 24% of all current and former veg*ns develop health issues from the diet (19% if you only include issues meat products cured quickly). I’m really sad to only be giving you this one study, but most of the literature is terrible (see below).

The Faunalytics study has a fair number of limitations, which I went into more detail on here. My guess is that their number is a moderate underestimate of the real rate, and a severe underestimate of the value for naive vegans in particular, but 24% is high enough that I don’t think the difference matters so I’ll use that for the rest of the post.

Evidence I’m looking for

The ideal study is a longitudinal RCT where diet is randomly assigned, cost (across all dimensions, not just money) is held constant, and participants are studied over multiple years to track cumulative effects. I assume that doesn’t exist, but the closer we can get the better. 

I’ve spent several hours looking for good studies on vegan nutrition, of which the only one that was even passable was the Faunalytics study. My search was by no means complete, but enough to spot some persistent flaws among multiple studies. I’ve also spent a fair amount of time checking citations made in support of vegan claims, only to find the study is either atrocious or doesn’t support the claim made (examples in the “This is a strawman…” section). There is also some history of goalpost moving, where an advocate cites a study, I criticize it, and they say it doesn’t matter and cite a new study. This is exhausting. 

I ask that you only cite evidence you, personally, find compelling and are willing to stand by, and note its flaws in your initial citation. That doesn’t mean the study has to be perfect, that’s impossible, but you should know the flaws and be ready to explain why you still believe the study. If your belief rests on many studies instead of just one (a perfectly reasonable, nee admirable, state), please cite all of them. I am going to be pretty hard on people who link to seriously flawed studies without disclosing the flaws, or who retract citations without updating their own beliefs.

A non-exhaustive list of common flaws:

  • Studies rarely control for supplements. I’m tentatively on board with supplements being enough to get people back to at least the health level they had as an omnivore, but you can’t know their effect with recording usage and examining the impact.
  • I’ve yet to see a study that controlled for effort and money put into diet. If vegans are equally healthy but are spending twice as much time and money on food, that’s important to know.
  • Diet is self-selected rather than assigned. People who try veganism and stick with it are disproportionately likely to find it easy.
    • I don’t expect to find a study randomly assigning a long term vegan diet, but I will apply a discount factor to account for that. 
  • Studies are snapshots rather than long-term, and so lose all of the information from people who tried veganism, found it too hard, and quit.
    • Finding a way around this is what earned Faunalytics my eternal gratitude.
  • Studies don’t mention including people with additional dietary challenges, which I think are a very big deal.
  • Veganism status is based on self-identification. Other studies show that self-identified vegans often eat enough meat to be nutritionally relevant.
  • Studies often combine veganism and vegetarianism, or only include vegetarians, but are cited as if they are about veganism alone. I think vegetarianism is nutritionally much closer to omnivorism than veganism, so this isn’t helpful.
  • All the usual problems: tiny samples, motivated researchers, bad statistics. 
  • Some studies monitor dietary intake levels rather than internal levels of nutrients (as measured by tests on blood or other fluids). There are two problems with this:
    • Since RDA levels run quite high relative to average need, this is unfairly hard on vegan diets. 
    • Nutrition labels aren’t always corrected for average bioavailability, and can’t be corrected for individual variation in digestion. Plant nutrients are on average less bioavailable (although I think there are broad exceptions, and certainly individuals vary on this), so that’s perhaps too easy on plant-based diets.
  • Most studies are done by motivated parties, and it’s too easy to manipulate those. I wouldn’t have trusted the Faunalytics study if it had come from a pro-meat source.

A non-exhaustive list of evidence I hope for:

  • Quantifying the costs (across all dimensions) of dietary changes, even if the study doesn’ control for them
  • AFAICT there is no large vegan culture- the closest is lacto-vegetarian with individuals choosing to aim higher, and cultures that can’t afford meat often. Evidence of cultures with true, lifelong veganism (excluding mother’s milk) would be very interesting.
  • Studies that in some way tracking people who quit veganism, such that it could detect health issues driving people to quit. 
  • What happens to health when a very poor community earns enough to have access to occasional meat?
  • What happens when people from a lacto-vegetarian or meat-sparse culture move to a meat-loving one?
  • Studies on the impact of vegan nutritional education- how much if any does it improve outcomes?
  • What happens to people who are forced to give up animal products suddenly, for non-ethical reasons? I’m thinking of things like Alpha-gal Syndrome creating an immune response to red meat, adult onset lactose intolerance, or moving to a country that deemphasizes meat.
  • Ditto for the reverse.
    • I’m especially interested in people with dietary difficulties.
  • Studies comparing veganism and vegetarianism, especially in the same person.

 Preemptive responses to counter-arguments

There are a few counter-arguments I’ve already gotten or expect to get shortly, so let me address them ahead of time. 

“You’re singling out veganism”

Multiple people have suggested it’s wrong for me to focus on veganism. If I build enough trust and rapport with them they will often admit that veganism obviously involves some trade-offs, if only because any dietary change has trade-offs, but they think I’m unfairly singling veganism out.

First off, I’ve been writing about nutrition under this name since 2014. Earlier, if you count the pseudonymous livejournal. I talk about non-vegan nutrition all the time. I wrote a short unrelated nutrition post while this one was in editing. I understand the mistake if you’re unfamiliar with my work, but I assure you this is not a hobby I picked up to annoy you.

It’s true that I am paying more attention to veganism than I am to, say, the trad carnivore idiots, even though I think that diet is worse. But veganism is where the people are, both near me and in the US as a whole. Dietary change is so synonymous with animal protection within Effective Altruism that the EAForum tag is a wholly-owned subsidiary of the animal suffering tag. At a young-EA-organizer conference I mentored at last year, something like half of attendees were vegan, and only a handful had no animal-protecting diet considerations. If keto gets anywhere near this kind of numbers I assure you I will say something.

“The costs of misinformation are small relative to the benefits of animals”

One possible argument for downplaying or dismissing the costs of veganism is that factory farming is so bad anything is justified in stopping it. I’m open to that argument in the abstract, but empirically I think this isn’t working and animals would be better off if people were given proper information. 

First, it’s not clear to me the costs of acknowledging vegan nutrition issues are that high. I’ve gotten a few dozen comments/emails/etc on my vegan nutrition project of the form “This inspired me to get tested, here are my supplements, here are my results”. No one has told me they’ve restarted consuming meat or even milk. It is possible people are less likely to volunteer diet changes, although I do note I’m not vegan.

But even if education causes many people to bounce off, the alternative may be worse. 

That Faunalytics study says 24% of people leave veg*nism due to health reasons. If you use really naive math, that suggests that ignoring nutrition issues would need to increase recruitment by 33%, just to break even.  But people who quit veganism due to health issues tend to do so with a vitriol not seen in people leaving for other reasons. I don’t have numbers for this, but r/exvegans is mostly people who left for health reasons (with a smattering of people compelled by parents), as are the ex-vegans angry enough to start blogs. Even if they don’t make a lifestyle out of it, people who feel harmed are less likely to retry veganism, and more likely to discourage their friends.

I made a toy model comparing the trade off of education (which may lead people to bounce off) vs. lack of education (which leads people to quit and discourage others). The result is very sensitive to assumptions, especially “how many counterfactual vegans do angry ex-vegans prevent?”. If you put the attrition rate as low as I do, education is clearly the best decision from an animal suffering perspective. If you put it higher it becomes very sensitive to other assumptions. It is fairly hard to make a slam-dunk case against nutritional awareness, but then, (points at years of nutrition blogging) I would say that.

“The human health gains are small relative to the harms to animals” 

I think this is a fair argument to make, and the answer comes down to complicated math. To their credit, vegan EAs have done an enormous amount of math on the exact numeric suffering of farmed animals. But honest accounting requires looking at the costs as well.

“The health costs don’t matter, no benefit justifies the horror of farming animals”

This is a fair argument for veganism. But it’s not grounds to declare the health costs to be zero.

It’s also not grounds to ignore nutrition within a plant-based diet. Even if veganism is healthy for everyone and no harder a switch than other diets, it is very normal for dietary changes to entail trade-offs and have some upfront costs.  The push to deny trade-offs and punish those who investigate them (see below) is hurting your own people. 

“This is a strawman, vegans already address nutrition” 

I fully acknowledge that there are a lot of resources on vegan nutrition, and that a lot of the outreach literature at least name-checks dietary planning. But I talk to a lot of people (primarily young EAs focused on non-animal projects) with stories like this one, of people going vegan as a group without remembering a single mention of B12 or iron. I would consider that a serious problem even if I couldn’t point to anything the movement was doing to cause it.

But I absolutely can point to things within the movement that create the problem. There are some outright lies, and a lot more well-crafted sentences that are technically correct but in aggregate leave people with deeply misleading impressions. 

While reading, please keep in mind that these are formal statements by respected vegans and animal protection organizationss (to the best of my ability to determine). All movements have idiots saying horrible things on reddit, and it’s not fair to judge the whole movement by them. But please keep that context in mind while reading: these were not off-the-cuff statements or quick tweets, but things a movement leader thought about and wrote down. 

  • There are numerous sources talking about the health benefits of veganism. Very few of them explicitly say “and this will definitely happen with no additional work from you, without any costs or trade-offs”, but some do, and many imply it.
    • Magnus Vindling, who has published 9 books and co-founded the Center for Reducing Suffering, says :”Beyond the environmental effects, there are also significant health risks associated with the direct consumption of animal products, including red meat, chicken meat, fish meat, eggs and dairy. Conversely, significant health benefits are associated with alternative sources of protein, such as beans, nuts, and seeds. This is relevant both collectively, for the sake of not supporting industries that actively promote poor human nutrition in general, as well as individually, to maximize one’s own health so one can be more effectively altruistic.”
  • This Facebook post from Jacy Reese Anthis, saying vegan dogs and cats can be perfectly healthy. Jacy was a leader among animal EAs until he left for unrelated reasons in 2019. He cites two sources, one of which supports only a subset of his claims, and the other of which actively contradicts them.
      • Apologies for the tiny image, WordPress is awful. If you right-click>open in new tab it will load a larger version.
    • His first source does say veganism can work, in dogs, but says nothing about cats.
    • His second source cites one person who says her cat is fine on a vegan diet but she doesn’t tell vets about it. The veterinarians quoted say dogs can be vegetarian and even vegan with some work. The statement on cats is ambiguous: it might be condemning only vegan diets, or both vegan and vegetarian. It rules out even vegetarian diets for young or breeding animals.

      The piece ends with “When people tell me they want to feed [their pet] a vegan diet, I say, ‘Get a goat, get a rabbit”.
    • Normally I would consider a 7 year old Facebook off-limits, but Jacy has a blue check and spent years doing very aggressive vegan advocacy on other peoples’ walls, most of which he has since deleted, so I think this is fair game. 
  • There is a related problem of motte-and-baileying “one day we will be able to have no-trade-off vegan diets, thanks to emerging technologies” and “it’s currently possible with no trade offs right this second”, e.g.: “Repudiating what “obligate carnivore” means – Kindly, but stridently, we have to correct folks that obligate carnivore stems from observation, not a diet requirement. This outdated thinking ignores the fundamental understanding of biochemistry, nutrition, and metabolism, which has only developed since the initial carnivore classification.”
  • In Doing Good Better, EA leader Will MacAskill advocates for a vegan diet to alleviate animal suffering, without mentioning any trade-offs. In isolation I don’t think that would necessarily be the wrong choice; the book is clearly about moral philosophy and not a how-to guide. But it is pushing individuals to change their personal diet (as opposed to donating to vegan recruitment programs), so I think it should at least mention trade-offs.
    • Apologies for the tiny image, WordPress is awful. If you right-click>open in new tab it will load a larger version.
  • name-checks “a balanced diet” but the vibe is strongly “veganism is extra health with no effort”:
    • “According to the Academy of Nutrition and Dietetics, a well-planned vegan diet is nutritionally adequate and appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.1 Everyone should have a balanced diet to be healthy, not only vegans. In fact non-vegans may well have unbalanced diets which are not good for their health. In order to be healthy we don’t need to consume certain products, but certain nutrients. Vegans can ingest those nutrients without having to eat animal products.”
    • “Being vegan is easier than you may think. Finding vegan food and other alternative products and services that do not involve animal exploitation is increasingly easier. It is true that some people may experience a lack of support from their family or friends or may find it extra challenging to stop eating certain animal products. However, other people can help you with that, especially today, given that internet and social networks have made it possible to get information and help from many other people. It is important to identify the factors that may be hindering your transition to veganism and look for assistance and encouragement from other people.”
    • Do I need to consult a doctor or nutritionist before becoming vegan?
      While this can be useful, as in the case of a planned non-vegan diet, it is not necessary. A vegan diet is suitable for people of all ages and conditions. A vegan nutritionist may help plan custom menus to meet specific requirements – for instance, if you are an athlete or if you want to gain or lose a lot of weight as a vegan. It is always advised to consult a nutritionist regularly for a check-up. However, it is important to note that some nutritionists are biased and don’t know a lot about vegan nutrition. Note also that medical doctors are often not experts on nutrition.”
  • EA-Foundation says veganism requires “appropriate planning”, but that this is easy 
  • That Faunalytics vegan study, which I mostly loved, contains the following: “Former vegetarians/vegans were asked if they began to experience any of the following when they were eating a vegetarian/vegan diet: depression/anxiety, digestive problems, food allergies, low cholesterol, an eating disorder, thyroid problems, protein deficiency, B12 deficiency, calcium deficiency, iron deficiency, iodine deficiency, vitamin A deficiency, vitamin D deficiency, zinc deficiency. The findings show that: – 71% of former vegetarians/vegans experienced none of the above. It is quite noteworthy that such a small proportion of individuals experienced ill health.”
    • 29% isn’t small. You can argue that’s an overestimate, but they’re accepting the 29% number, and are saying it doesn’t matter. 

Why is this so hard to talk about?

This is probably the least important section. I’m including it mostly in the hope it lowers friction in the object-level conversation. 

The stakes are so high

Hardcore vegan advocates believe we are surrounded by mass torture and slaughter facilities killing thousands of beings every day. That’s the kind of crisis that makes it hard to do really nuanced math people may use to justify ignoring you. 

Vegans are sick of concern trolls

Vegans frequently have to deal with bad-faith interrogation of their choices (“wHxt ABuoT proTEIn?!?!”). I imagine this is infuriating, and I’ve worked really hard to set myself apart by things like investing hundreds of hours of my time, much of which was unpaid, and working to get vegans the nutrition they needed to stay healthy and vegan.

Typical minding/failure of imagination

People who find veganism easier are disproportionately likely to become and stay vegan. That’s what the word “easy” means. Then some of them assume their experiences are more representative than they are, and that people who report more difficulty are lying. 

E.g. this comment on an earlier post (not even by a vegan- he was a vegan’s partner) said “there is nothing special one needs to do to stay healthy [while eating vegan]” because “most processed products like oat milk, soy milk, impossible meat, beyond meat, daiya cheese are enriched with whatever supplements are needed”. Which I would describe as “all you need to do to stay healthy while vegan is eat fortified products”. That’s indeed pretty easy, and some people will do it without thinking. But it’s not nothing, especially when “no processed foods” is such a common restriction. Sure enough, Faunalytics found that veg*ns who quit were less likely (relative to current veg*ns) to eat fortified foods. 

That same person later left another comment, conceding this point and also that there were people the fortified foods didn’t work for. Which is great, but it belonged in the first comment.

Or this commenter, who couldn’t imagine a naive vegan until an ex-vegan described the total ignorance they and their entire college EA group operated under. 

Lies we tell omnivores

Ozy Brennan has a post “Lies to cis people”. They posit that trans advocates, faced with a hostile public, give a story of gender that is simplified (because most people won’t hear the nuance anyway), and prioritizes being treated well over conveying the most possible truth. The intention is that an actual trans person or deeply invested ally will go deeper into the culture and get a more nuanced view. This can lead to some conflict when a person tries to explore gender with only the official literature as their guide.

Similarly, “veganism requires no sacrifice on any front, for anyone” is a lie vegans tell current omnivores. I suspect the expectation, perhaps subconscious, is that once they convert to veganism they’ll hang around other vegans and pick up some recipes, know what tests to get, and hear recommendations for vegan vitamins without doing anything deliberately. The longer sentence would be “for most people veganism requires no sacrifice beyond occasional tests and vitamins, which is really not much work at all”. 

But this screws over new vegans who don’t end up in those subcultures. It’s especially bad if they’re surrounded by enough other vegans that it feels like they should get the knowledge, but the transmission was somehow cut off. I think this has happened with x-risk focused EA vegans, and two friends described a similar phenomenon in the straight-edge punk scene

Failure to hear distinctions, on both sides

I imagine many people do overestimate the sacrifice involved in becoming vegan. The tradeoff is often less than they think, especially once they get over the initial hump. If omnivores are literally unable to hear “well yes, but for most people only a bit”, it’s very tempting to tell them “not at all”. But this can lead even the average person to do less work than they should, and leaves vegans unable to recognize people for whom plant based diets are genuinely very difficult, if not impossible.


I think veganism comes with trade-offs, health is one of the axes, and that the health issues are often but not always solvable. This is orthogonal to the moral issue of animal suffering. If I’m right, animal EAs need to change their messaging around vegan diets, and start self-policing misinformation. If I’m wrong, I need to write some retractions and/or shut the hell up.

Discussions like this are really hard, and have gone poorly in the past. But I’m still hopeful, because animal EAs have exemplified some of the best parts of effective altruism, like taking weird ideas seriously, moral math, and checking to see if a program actually worked. I want that same epistemic rigor applied to nutrition, and I’m hopeful about what will happen if it is. 

Thanks to Patrick La Victoire and Raymond Arnold for long discussions and beta-reading, and Sam Cotrell for research assistance.

Product Endorsement: Food for sleep interruptions

Do you wake up before you want to and struggle with getting back to sleep when you do? One thing (out of many) that can cause this is low blood sugar*. If this is your issue, it is easily solved by eating high-fat, high-protein food.

My evidence on this is purely anecdotal; I learned this from r/adviceanimals in 2012, so the intellectual pedigree is weak. But I added ~one full sleep cycle to my night when I tried it, which lasted for years until I was forced to stop due to medication requiring an empty stomach (I now use ketone esters). A month ago my dad went from “3-5 hours/night, 3 hours awake, maybe more sleep after that” to “8-9 hours of near-continuous sleep, 1 night per fortnight a mere 6 hours” by keeping peanut butter by his bed. Downside: he’s now useless for testing the magic vibrating bracelet I’m so hyped about.

This is very easy to test. Keep some nuts by your bed; if you wake up, eat some. If you fall back asleep, congratulations on fixing your problem. There are more complicated things you can do with your evening diet to try and prevent early wake-ups entirely but I feel very muddled about these and don’t have good suggestions.

If you’re doing intermittent fasting, ketone esters (affiliate link) don’t work for many people but are great if you’re one of the lucky ones (I am), and ~don’t count as eating. MCT oils (affiliate link) work on the same principle and so may be an alternative, but I haven’t tested them personally.

I am not a doctor, anything with a real effect can hurt you, be careful not to choke or attract ants, etc. 

*It’s not clear to me if this is actually low blood sugar as measured glucose in your bloodstream, or naturopathic “low blood sugar”, meaning problems you fix by eating, but I don’t care. 

Playing with Faunalytics’ Vegan Attrition Data

I’ve been looking for data on nutrition-related health problems in vegans, and it has been hard going. By far the best I’ve found has been this 2014 survey from Faunalytics (a data science org focused on animal protection), which finds 29% of ex-vegans + vegetarians had health issues plausibly traced to veganism, but that study is still missing several factors I care about. I made up a model to see how those factors might affect the answer, and found the answer was “moderately, but not enough to change anyone’s plans”.

This is mostly intended for me to reference later, I expect most people to skip it.

I want to give Faunalytics a lot of credit here. They used a professional survey provider to poll a large number of people (11,399, although most of them wasted as they had never been veg*n), and AFAICT the survey was well designed for their goals. They were extremely forthcoming in sharing their raw data and provided some assistance in interpretation (although ultimately not enough to make it usable for me 😞 ). 

But even though they are the best I’ve found, the data is still pretty limited (~1100 ex-veg*ns), and the questions weren’t optimized for my inquiry.  I dislike that they combined vegans and vegetarians into a single category (which I label veg*nism here), but I think that was a very understandable combination of sample size issues and the fact that very few vegans don’t pass through vegetarianism. I can’t pull data out of thin air, but I can at least use guesstimate to get a range of how those factors might affect the answer.  So I made a model that linearly applied a number of factors I think are important. This is really crude, and some of the factors shouldn’t be linear, but it was a place to start. 

This is pretty informal. You could easily argue I missed important factors, or assigned the ones I made up the wrong value. I encourage you to make that argument in comments, or play with the model yourself. 

We’ll start with Faunalytics’ (page 6) raw number, which showed 29% of ex-veg*ns reported coming down with a problem plausibly attributed to their diet.  

But I care about all veg*ns, not just those who quit. In this sample, 16% of people who had ever tried veg*nism were still at it.  You could assume that set have never had health problems, or they would eventually hit the same 30%, or somewhere in between. Faunalytics showed current veg*ns tend to have been on the diet longer than the average time-to-quit of ex-veg*ns, and have better nutrition and supplementation, so “the same amount” seems much too high. I set it to 0 to 20% (log-normal distribution – so biased towards the low end).

[This still focuses on the number of self-identified vegans, not vegan-months or total animal products consumed over time, but that’s an even bigger can of worms]

How do we know diet was to blame for health issues? One easy way is to look at the percentage of people who got better when they resumed eating meat, which Faunalytics reports to be 80% improved within 3 months: I assume all of those were caused by veg*n diet. What about people still impaired after 3 months of resuming consumption of animal products? Probably some will get better later, some will never improve but the problem was still caused by veg*n diet, some have a problem veg*nism didn’t cause but will make worse (e.g. they developed a nut allergy and it made veg*nism too hard) and some have a completely unrelated problem that they are misattributing to veg*n diet. I guessed the diet-related proportion was 5-50% (of the 20% not responding in three months), with a normal distribution (so biased towards the average of that range).

Health is the most sympathetic reason to quit veg*nism, so we should expect people to overreport it. Except that the percentage of people who described themselves as quitting over health reasons (26%) was smaller than the percent who reported at least one health issue easily caused by veg*nism (29%), although higher than percent of people who developed those issues and then recovered within 3 months of resuming meat consumption (23%). I estimated the percentage of reported-health issues that were fake as 0-50%, with log-normal distribution. 

Survey organizers tend to get the results they want, and Faunalytics is an animal protection org. They outsourced the actual survey administration, which is helpful but not a total fix. I guessed that they biased results 0-50% too low, with a log-normal distribution.

I am most interested in people practicing a veg*n diet naively (meaning: they did zero research and thought into nutrition), but that 29% includes all knowledge and effort levels (although in practice current veg*ns were more likely to be eating well). I added a factor for “if naive”, and guessed the size of the impact if *everyone* was naive was between 0 and 100% (meaning, no-effect to double effect – 100% isn’t the top of the scale here), with a log-normal distribution.

People often identify as veg*n while consuming animal products, which improves their nutrition.  The first study I found said 50% of vegetarians admitted to eating meat while identifying as vegetarian – but that included people who ate meat even once, which isn’t necessarily enough to matter nutritionally. On the other hand, this is the kind of thing people are likely to underreport. I added a multiplier for that and guessed it to be an additional 10%-50%, with a log-normal distribution.

Not all issues caused by veg*nsim get diagnosed or properly traced to diet. I added a multiplier for that, +10% to 40%, with a log-normal distribution.

If you combine all my wild-ass guesses, you get…. 37% (0%-56%) of veg*ns eventually developing health issues from their diet. That’s already higher than Faunalytics’ 29%, but remember my denominator includes current veg*ns and theirs doesn’t. The comparable number, looking only at people who quit and assuming everyone who develops health issues quit over them, is 44%,which is 65% higher than Faunanalytic’s estimate. 

I’m especially interested in vegans (but not vegetarians) who enter the diet naively. I made up numbers for these as well, and ultimately got 95% (17%-100%) of naive vegans developing health issues. I know too many healthy (so far) naive vegans for that to seem right, so I changed my assumptions and got it down to 56% (3%-88%), which seems plausible if you use a strict definition of naive.

What does this mean? Primarily that I feel better about my intuition that Faunalytics is underestimating the extent of the problem, but because I already considered 30% a big deal there’s no qualitative shift in how I think about it.  If you have different intuitions, you test out them out in guesstimate.

Lessons learned from offering in-office nutritional testing


I’ve talked previously about my concerns with nutritional deficiencies in effective altruists who go vegan for ethical reasons, especially those who don’t have a lot of contact with the broader vegan culture. No one else seemed very concerned, so I launched a tiny project to test people in this group and see if they were in fact deficient. This is a report on the latest phase of the project. 

To cut to the chase:

  • It was very easy to find lots of deficiencies, although due to a severely heterogenous sample and lack of a control group this doesn’t provide useful information about if veganism is at fault.
  • Finding these deficiencies probably leads to useful treatment, but not as much as I’d hoped.
  • There are still a lot of operational issues to work out. My guess is that the ideal would require more work (to encourage participants to act on their results) or less (by focusing on education but not providing testing). 
  • I am currently looking for a co-founder to properly investigate the impact of veganism on nutrition. 

My main question here was “is there low-hanging fruit in treating nutritional deficiencies in this group, and if so how do we pluck it?” An important part of that is “how prevalent are deficiencies?”, but I had substantially more uncertainty around “do people treat deficiencies you find?” and “does the treatment lead to improvements in anything we actually care about?” That prioritization (and budget issues) led the experimental design to focus on operational issues and outcomes, and deprioritized getting the kind of clean data that would let me compare vegan and non-vegan outcomes. Similarly this write-up is mostly focused on showing the problem exists at all and building metis of investigation and treatment, rather than estimating prevalence. 

Which is to say to to everyone planning on @ing me to complain about the sample size, heterogeneity, or mediocre statistics: you are right that this sample is not very informative about base rates of deficiencies in vegans or anyone else. If someone claimed it was, they would be committing an epistemic sin. However, this particular post is focused on “how much effort is it to get nutritional issues addressed, and is that effort worth it?”. Given that, any complaints about the terrible sampling will be considered to be offers of assistance in running the much larger study that could answer the prevalence question


(if you’ve read the previous posts, this will be review)

Last year I worked in a co-working space focused on existential risks, which is anything that might really end everything. Because x-risk is a popular topic within the effective altruism movement, many participants in the space were EAs. Another big topic within effective altruism is animal suffering, especially farmed animal suffering. This has led many EAs in the office to go vegan or at least vegetarian for ethical reasons, without making animals the focus of their lives. And when I asked them, many had put no thought into how to give up animal products in a healthy way.

Which of course would have been fine if they were eating well. My personal opinion is that most people’s optimal diet contains small amounts of animal products, but lots of people are eating suboptimally for lots of reasons and I don’t consider it my problem. But the number of fatigue and concentration issues were… I don’t actually know if they were high. I don’t know what baseline to compare them to. But it wasn’t low enough to reassure me. Neither did the way the vegans talked about nutrition, and in particular the fact that more than one person was doing keto vegan and still wasn’t investigating nutrition. 

None of this meant there was necessarily a problem, but I was suspicious. So I got a small grant to solve this with numbers. 

First I tried broad spectrum testing, which led me to identify iron deficiency as the main concern.

Then I did a short investigation into the actual costs of iron deficiency, which motivated a number of people to get tested, some of whom got in touch after the fact. 

In my last post I implied I was stopping the project, and wrote next steps as if someone else would be doing them. I ended up getting a follow on grant so pushed forward with round two on my own, which is what this post is about. 

Round 2 concrete steps

I followed the steps laid out in my previous post almost exactly.

  1. I brought in a company to draw blood from participants in the Lightcone office. This was expensive, probably 2-4x having people buy lab orders online, which is still more expensive than doctor-ordered tests with insurance.
    1. I say I brought them in – I in fact hired someone to handle the company and interface with participants. Aaron Silverbook was great, pretty much best case scenario for hiring a subcontractor, although still not as good as an invested co-founder.
  2. Based on previous results and nutritional folk wisdom my test priorities were ferritin (the best proxy for iron), B12, and Vitamin D. I threw in some other iron tests because they were very cheap.
  3. We had applicants fill out a form detailing their diet and any fatigue issues.
  4. Aaron picked 20 participants and made a schedule for testing them. Prioritization was: Fatigue issues > vegan > vegetarian > whoever happened to be in the office that day.
    1. This was my favorite part of having a contractor because scheduling involved some very intense math around prioritization and availability and from my perspective it was no work at all.
    2. Prioritizing people with fatigue issues probably made the immediate impact higher, and was useful for estimating the upper bound of possible impact, but ruined the sample for calculating base rates. It means I can’t really compare vegans vs. omnivores, because both were selected for having potentially-nutrition-caused problems. I had hoped to maybe compare vegans with fatigue to omnivores with fatigue, because the tired vegans had more nutritional issues that would be pretty suggestive, but ultimately didn’t have enough data to bother.
    3. I flat out didn’t have enough money to do a good study capable of establishing high confidence prevalence rates, even if that had been my primary goal. Putting aside sample size, good sampling requires getting representative participants, many of whom have no reason to get tested. They’re not intrinsically motivated, so you have to pay them to get tested. 
  5. The company comes into the office. There are a bunch of day-of headaches that Aaron handles beautifully and I am completely uninvolved with because he is good at his job.
  6. Results go out. Some participants received results over email, some were told to go to the company’s portal, some may never have gotten a notification at all. More on this in the Difficulties section.
  7. I ask Aaron to get results from participants to me, for analysis. This goes less well- I wasn’t sufficiently clear on what information I wanted in the form, and he’s gotten busy with other stuff and had less time to devote to my project, which has already gone longer than anticipated due to issues with the lab. Response rate is poor- we eventually get 13 people out of 20.
  8. I send out a second form asking for more information, and a bunch of emails harassing people to do both forms. Response rate continues to be poor, only 8 people this time. 
  9. 3 months after testing I followed up with the people with the worst scores to see if they had gotten treatment.

Project Difficulties

Other People’s Fault

I cannot say enough bad things about BayAreaPLS, the company we hired to come into the office and do testing.

First and most importantly, they just forgot to run the ferritin test for half the participants. They did the other tests, there was no reason to not do that one in particular, they just… didn’t. Their initial attempt to make up for this was an offer to not charge me for tests they didn’t do. I pushed back fairly hard and they agreed to some actual discounting. It’s been 2.5 months and they have yet to send me that follow-up invoice, which I guess is technically good for me but makes me feel worse overall.

Second, the results were hard to retrieve. Some participants never got results at all even after following the instructions, and I have no way to debug whose fault that is. Others didn’t bother to retrieve results because it was too hard. The happiest people were the ones who got their results over email, which is a HIPAA violation the company claims to have done by accident. Much like the lack of the second invoice, the emailed results are technically good for me but leave me more concerned about the company.

Even for people who did get results it took almost two weeks, which was not great for momentum.

Lastly the company used different deficiency thresholds for different people. They say this was based on sex and age, but they didn’t get that information from everyone (sounds like incompetence on their part), so some people got a list of thresholds. It ended up creating a moderate amount of confusion and friction, especially because I couldn’t tell what variation came from age/sex (which I mostly want to ignore) vs. the norms of a particular test (which I very much don’t). People are slow to act on results in general so the additional friction was quite costly. 

My Fault or Inherent Difficulties

Not all of these were literally caused by me, but they all fall under “my responsibility to anticipate and handle”.

I mentioned in my last post that some participants were kind of insistent on getting a lot of help from me, even after I explicitly told them something was outside my bailiwick and needed a doctor. I tried to fix that this time by hiring Aaron. That worked on that one issue, but made it harder to catch new problems. If the plan had been for people to directly show me their results and receive coaching I would have caught the missing test values much earlier. I’m not sure there is a way to have someone available enough to get all the relevant questions from participants without also having to deal with a bunch of irrelevant ones, including inappropriately persistent ones. The difference between the two just isn’t obvious with the knowledge most participants have, and emotions run so high around health stuff.

It’s hard to estimate the rate of acting on results because the people who don’t act are less likely to fill out the follow-up surveys, but my sense is it’s not good, and probably <50%. I also strongly suspect the rate of acting on results would have been higher if there had been in-person follow-up. 

The guidelines I sent participants emphasized vitamin D and ferritin because it didn’t occur to me anyone could see an anemia result on the page and not rush to treat it, but at least two people scored as anemic and, as of three months later, had not treated it. 

The lab obeyed HIPAA enough to only send results to participants, not directly to me, so I needed participants to forward them. Of 20 participants, 13 did so. Only 8 participated in the separate follow-up questionnaire (arguably my fault for asking for two separate forms, but there was good reason to ask for results quickly and do the follow-up a little later). 20 people with varying motivations for testing was never going to be strong evidence for anything systemic, but the low response rate makes it even harder to draw conclusions.

My emails to participants sometimes went to spam, possibly due to use of BCC, which was necessary to meet the privacy commitments I made in the application.

What were the total costs? 

As a ballpark:

  • ~$270 per participant (if they had done all the tests for everyone).
  • 0.5 hours per participant, including follow-up and the disruption to their schedule. If you want to be really conservative you could call this an hour to account for the disruption from transitions.
  • ~10 hours of Aaron’s time
  • ~20 hours of my time
  • $30 per deficient person for supplements (not covered by the study)

If you value everyone’s time roughly the same, that means that to break even we need to save one person 30 hours + ~$5700 (ignoring the information gained). 

If you want to complicate that math you can add any of: discount rate on time or money, exchange rate between ops time/my time/participant time, cost of unnecessary or counterproductive treatment, knowledge gained from this round can make the next round cheaper, the fact that most of my time went to a write-up that shouldn’t really be billed to participants, but a better program would have spent more time with participants.

Results and Benefits

Test Results

I should remind you here that the sample was a mix of 20 ethical EA vegans, vegetarians, people with fatigue issues, and people who happened to be in the office. Even a very large sample wouldn’t be perfectly predictive unless you had the exact same mix of participant types, and this sample was tiny. So the right way to look at these results is “is this enough to think there’s a problem?” and “did people do helpful things with the information?” not “at what exact rate does this population develop ferritin issues?”

With those caveats, here is the data from participants that reported back. I have ferritin results for 8 people and all other results for 13. 

  • 85% reported energy problems
  • 15% were honest-to-god anemic
  • 65% had low ferritin (30% clinically deficient) (none of the anemic people had ferritin tests done, so there is no overlap between this group and the anemics. There were non-anemic people without ferritin tests, so I assume this is a coincidence)
  • 60% had low vitamin D (15% clinically deficient)
  • A total of 80% had low scores in at least one of hemoglobin, ferritin, or vitamin D
  • 0% had low B12 (many were on supplements, but I haven’t correlated that with serum B12 levels because at this sample size and heterogeneity there is no point)

Some of the non-reporting was random due to the lab’s incompetence, but it’s not impossible unhealthy participants were more likely to report back. If you want to be extremely conservative and assume every missing value was A+ healthy, the results are still quite concerning: 

  • 10% anemic
  • 25% low-in-my-opinion ferritin, 10% clinically deficient (still no overlap with the anemics)
  • 35% low-in-my-opinion vitamin D, 10% clinically deficient
  • B12 is still great, good job everyone

I Lead This Horse To Water – You Won’t Believe What Happened Next

But finding results isn’t very meaningful if no one acts on them. Of the 8 people who filled out the follow-up survey, 75% changed either diet or supplements, and 1 additional person kept going with supplements they would otherwise have dropped. I assume this is overreporting because people who changed things are more likely to respond, but if you assume none of the nonresponders did anything that’s still 30% of people changing something.

Of the 5 who changed something and answered the relevant question, 40% said they thought they saw an improvement (~1 month after they received results). I don’t consider that particularly strong evidence in either direction- it can take time for deficiencies to heal, but it’s also easy to placebo yourself into seeing an improvement that isn’t there. The real test will be the six-month follow-up. 

Three months after testing I followed up with the two identified anemics to make sure they were getting treatment. Neither was, despite having health issues plausibly caused by anemia. They’ve both indicated vague plans to follow up now that I’ve pushed them on it. 

Is in-office testing worth it?

I believe this round of testing was better than not doing in-office testing, but there is a lot of room for improvement.

My absolute wild-ass-guess is that this saved between one and ten people (out of twenty participants) from anemia or a moderate iron deficiency, and this improved their life and productivity by 10% to 100% (mean around 20%). I acknowledge these are large ranges, but some problems are bigger than other problems. I’m ignoring vitamin D entirely here because I haven’t even attempted to quantify its value and its ardent fanclub has poisoned the literature.

Even in the worst case, a 5% chance at a 10% improvement is a big deal, so I think this was obviously worth it from a participant perspective. I think it’s a toss-up if it would be worth it for apparently healthy omnivores: my expected value for them is much lower, but people don’t always realize they’re operating at a deficit and catching them requires testing actually-healthy people as well.

I said above that we needed to save someone 30 hours + $6000 for the project to break even. Even one successfully treated anemic will blow that out of the water, so I don’t feel the need to do the more complicated math with discount rates and relative value of time, especially because any future round should either be less work or have a higher response rate.

Of course “break even” isn’t a very high bar. To go even further out on a limb: the median case of mild anemia easily costs someone two hours/day (source: had anemia one time).  This testing easily caught the anemia at least six months before it would otherwise have been caught (because everyone who was going to get tested on their own did so when I published my iron post).  That is, at a bare minimum, 360 hours someone otherwise wouldn’t have had. That’s a pretty great return rate for 40 hours (my time + Aaron’s time + participant time) +$6000.

Was the project overall worth it?

I would bet on yes, although a lot of information has yet to come in. 

I expect this project to have 6 lasting impacts:

  1. The treated health problems of participants.
  2. The secondary impact via participants’ work. 
  3. Public blog posts I write. My iron deficiency post, which motivated many people to get tested themselves, quite possibly more than received tests directly.
  4. Knowledge of how to do this more in the future. 
  5. Influence on Effective Altruism vegan culture.
  6. Animal suffering averted by making veganism more sustainable for participants.

#1 is what I calculated above, and think was already a sound success although not resounding.

#2 and #3 require making assessments of all individuals who received testing from the project or due to blog posts I wrote. That’s a combination of “vast amounts of missing information” and “judging individual merit” that makes it really uncomfortable to talk about in a public post. 

To be totally honest I’m on an “everything is bullshit” kick right now so deep in my soul I don’t think this paid off, but intellectually I think my standards are too high and this was a better project than average project in the space of existential risk. 

#4 and #5 depend on other people following up on this project. I absolutely believe they should, for all the other reasons but also because the return via #6 seems pretty good- health reasons are a common reason vegans go back to eating meat [It was hard to find a good source, but this shitty source says 26%. I’ll acknowledge that’s probably an overestimate, since health is the most virtuous reason to go back to eating meat.]

I can’t estimate #6 myself. I’m not familiar enough with vegan literature to sort good from bad here, and it wasn’t my main goal.

Then there are costs. The total grant was for a little less than $25k. I didn’t track my time very closely to avoid depressing myself, but my compensation is going to work out to a fraction of my normal hourly rate. If you count foregone client work you could argue the true cost was as high as $50k. 

My gut feeling is the project was straightforwardly worth it if you don’t track the foregone work. If you do, impact is dependent on having at least one of:

  • At least one of the impaired and successfully treated participants goes on to do high-impact work.
  • The iron post inspires at least 40 tests total, with a similar rate of finding and treating problems.
  • Follow-up projects exist and do good work. 
  • This work leads to more veganism, and you value that a lot. 

So can we blame veganism for the deficiencies?

This study doesn’t say anything one way or the other, which means I still think yes but you shouldn’t change your opinion based on the results. The sample is too small and skewed to compare deficiency rates in vegans and nonvegans. There were energetic omnivores with deficiencies and tired vegans with perfect scores so it’s clearly not deterministic. 

Next steps

I see three possible follow ups to this project:

Nutrition blogging

This is my default, although I don’t plan on writing many of these because there is only so much low hanging fruit and people have a very limited attention budget.  I have to be very judicious in what I suggest.

Mass testing to investigate deficiencies in effective altruism populations

Get the money to test a large enough representative sample, and run the tests with a proper control to actually estimate the cost of nutritional veganism. 

This is most useful if there are EA vegan leaders who won’t act on nutritional concerns now but would if the study demonstrated a problem. If this is you, I would love to talk to you about what you would consider sufficient to act on. 

Assuming the demand for this information is there, I still don’t think I want to run this project alone. First, it is a lot of work. Second…I know I said “assuming demand is there”, but I can’t picture a scenario where demand exists but no animal EAs consider this project worth working on. A collaborator would be both proof of investment and much better positioned than I am to get the information acted on. 

To that end, here is an ad for a co-founder. I will post it on this blog in a few days.

In office testing with real nutritional counseling

This can work, but only in a limited number of situations. You need a reason  (uninformed veganism, high fatigue rates) to suspect nutritional issues in lots of people sharing a space. There needs to be a reason people aren’t getting tested themselves that won’t also inhibit follow up (probably lack of money and existing relationship with a doctor). And even then it’s more of a hits-based model than a sure thing.  

My decision is easy because the office I was working out of closed, and in general I think most of the people in the bay area I would want to help have already been reached. The market is saturated for at least a year. There are other offices elsewhere in the world, and if you want to run this yourself I’m happy to act in an advisory capacity (especially if you share data), but it can’t really be an ongoing project in any one city. 


I finished most of this post planning on it being the end of my part of the project. I had hopes I would convince someone else to pick up the torch, and maybe even act as an advisor, but it seemed like the biggest problem was participant motivation, which I don’t feel equipped to solve. It was while I was writing this that I realized I wasn’t ready to let the broader issue of vegan nutrition go. I still believe the problem that offended my morals and epistemics is there and worth acting on.

But doing so is still very annoying, which is why I’m looking for someone to partner with on this. Someone who can handle the parts I’m bad at, point out where I’m wrong, and interface with the vegan EA community to get the results acted upon. If you’re interested, please reach out to

Thank you to the Survival and Flourishg Fund for funding this research, and Lightcone Infrastructure for hosting the grant and testing. I inflicted this draft on a number of people but want to especially thank Gavin Bishop. Daniel Filan didn’t beta read this post but he did vegan-check my co-founder ad and suggest the title “I Lead This Horse To Water – You Won’t Believe What Happened Next”.

Product Endorsement: Apollo Neuro

Short version: This $310 vibrating bracelet dramatically improved my sleep and moderately improved my emotional regulation. The return policy is pretty liberal so if this seems at all appealing I recommend trying it, or one of the cheaper alternatives I haven’t investigated. Between now and Mothers’ Day they are $300. 

[note: the link I use here is an affiliate link that gives you a $40 discount and me a $50 Amazon gift card] 


As a strong believer in luck-based medicine, I have a pretty liberal threshold for trying shit Facebook advertises to me. Most of it is crap, but every once in a while there is something amazing that justifies all the work and return fees. Previous purchases include resistance band clips that measure force applied, sleep-safe headphones that claimed to measure your HRV, and an infrared heat massage. But when I first looked at the Apollo Neuro’s website, it was too dumb even for me. The explanation for how it worked was a mix of absent and stupid, and the rush to provide scientific evidence was somehow worse than nothing. I only tried it because a friend raved about it. He had also thought it sounded deeply stupid and only bought it because his friend raved about it, and I can only assume she also thought it was stupid until someone raved about it to her, in a great circle of life. Now it is your turn to be told it sounds stupid but it works.

[For some people. My sample size is only three people.]

Benefits to me

My sleep improved a lot. I don’t have precise metrics for this because fitbit is stupid, but 1-3 times a week I wake up feeling drugged (positive valence) because my muscles are so relaxed. This never happened before the neuro unless I took actual drugs*. I also estimate my number of remembered wake-ups has been ~halved. 

The Neuro has about 8 hours of battery. When I started using it I always woke up with the battery drained, meaning I’d activated it repeatedly. I now wake up with it at 70-90% charge, partially because I wake up less and thus am not turning it back on, and partially because I use less intense vibration.

[*TBF I regularly take supplements for sleep, so what I really mean here is “unless I took more drugs than baseline”]

My emotional regulation improved as well. There were a number of stressful things I handled better than my baseline. Some of this is subjective, but there are a few things with obvious before-pictures. Most notably:

I have pretty bad medical anxiety, due most notably to dental malpratice leaving me with painful nerve damage, but also some other stuff. Last fall I had a doctor’s appointment on Friday, followed by friend’s child’s medical emergency on Saturday that, due to their newness to the country, I needed to be in charge for. I did it, but I was wrecked for at least a day afterwards, possibly more, and my partner had to put in a lot of emotional energy helping me recover. ~4 weeks into using the Apollo Neuro I had a dentist appointment in the afternoon, followed 8 hours later by a friend’s medical emergency requiring my attention and eventually a 3AM field trip to the ER for which I was the only available driver. I did have a little freak out once I was home, but I recovered to normal faster than I did from the incident in the fall despite that having been a less intense day with more help. 

I also found myself more decisively liking and disliking things, and noticing when things shifted. At parties the transition from “I’m enjoying this” to “I’m done” is clearer, without a lot of “maybe I should hold out and it will get better”. 


The website is stupid, so let me tell you how it really works. The Neuro is shaped like a watch with a large rectangular face. You can wear it around your wrist or ankle with a band, or clip it to clothes. When activated, it vibrates with oscillating intensity. There are 7 programs with varying oscillation patterns and durations: the wake-up program lasts five minutes with a short peak and shifts between off and on quickly, sleep spends longer in both phases and shifts between them much more slowly. Sleep is the longest program but also lowers intensity over time. You can configure the peak intensity but not duration or pattern, which I feel very oppressed by. 

You can change intensity, and pause and restart the last program from the watch, but to choose a program you need the smartphone app. It is impossible to use the watch without a smartphone, which is a serious quality of life issue for those of us with insomniac older relatives. 

The website talks about cumulative effects a lot, and is clearly pushing you to try for several weeks before judging it. There’s even some gamification for the first N hours. This felt to me exactly as necessary as a punch card from a heroin dealer. I loved it from the moment I put it on and found the little badges cheapening of my relationship with my device. But the cumulative effects part was true: as previously mentioned I needed less and less work from the Neuro to sleep, and lowered the intensity setting over time. When I first started most of the programs besides sleep and wake-up ran together, but at 6 weeks in I started really distinguishing the other programs and having strong preferences about which program, which changed over time. 

The website also advertises the Apollo for concentration problems, but I don’t know anyone who’s really tested that.

One thing I want to give the Apollo is that there is no subscription fee. You give them money and they give you the whole product and app. That should be standard but very much isn’t in the as-seen-on-FB crowd.

Cheaper Alternatives?

The Neuro is very expensive and seems like it can’t possibly cost that much to manufacture. For me paying them for the R+D was worth it. It would even have been worth a second one at the same inflated price, had my sleep not improved to the point I didn’t need it. 

Back when I thought I would need a second one to cover a full night of sleep I looked around for cheaper alternatives. None of them quite worked and I gave up when I no longer personally needed it, but if you’re motivated some might be worth checking out. 

The Senate works on a similar principle, but is no cheaper. Its programs are only 10 minutes, which is much too short for me. 

I tried a few sexual vibrators but even those with intermittent patterns transition from on to off much too quickly, which is how I figured out the gentle transition is so important. Presumably there are some that transition gently but I have no idea how to search for them. 

There are apps to vibrate your phone but they are mostly ad-ridden messes I couldn’t deal with. The one I managed to test had the same problem as the sexual vibrators. 

Products aimed at babies: these mostly run on external batteries, but they can be pretty cheap and many don’t require a smart phone. If you try any of these let me know because the alternative is teaching my elderly aunt to use a smart phone and I am not looking forward to it.


This product is very much in “immensely valuable to some people, price and quality of life issues limit its market for now”. If you have anxiety or sleep issues I seriously recommend trying it; the return fee looks to be about $20, although they’re less forthcoming than one might hope. If money is an issue or you’re just feeling curious you could also try the vibrating baby soothers. Amazon sells several and returns are usually free. 

If you do try the Apollo or any other product in the category I’d love to hear from you so I can share the information (please decide in your heart if you want to share your results before you try it, to avoid biasing the data). You can report your experience here

Thanks to my Patreon patrons for supporting this write up, and J for suggesting the Apollo to me in the first place.

Long Covid Risks: 2023 Update

Back in 2021 I wrote a post estimating the risk of long covid. Recently a client hired me to do an update, focusing on changes induced by Paxlovid and vaccination. This was a <5h project and the literature wasn’t very rich so nothing I say here is conclusive, but nothing I said last time was conclusive either so let’s enjoy this together. 

Some caveats: 

  • I spent 5 hours on this, and that includes client-specific work I’m not including here.
  • Research that met my standard was really scarce; ultimately each conclusion is based on a single study. My goal was data that includes a large population not selected for having long covid, where reporting was automated so you don’t need to worry about response bias. In practice, this means I used data from large medical systems with integrated reporting, like the American Department of Veteran Affairs, national medical systems, and HMOs. Surveys from long covid support groups were ignored with prejudice. 


Vaccination helps, a bit: Given a medically diagnosed infection (which means it was serious enough to actually get you to the doctor), up-to-date vaccination lowers the risk of long covid by about 20% (this does not include the reduction in risk of having diagnosable covid in the first place, which is substantial). 

Paxlovid helps, more: Nirmatrelvir, which is one of two drugs that make up Paxlovid, reduces long covid risk by about 30% for medically diagnosed infections (which means it was serious enough to actually get you to the doctor). An optimist might hope the other drug (which is in the same class, although most commonly used as an adjuvant) is also useful and round this to 50%.

Most symptoms are temporary: Long covid does tend to get better over time, but how quickly depends on the symptom.  At one year post-infection, the rate of heart issues is nearly indistinguishable from controls, but cognitive issues have a 50% chance of persisting. 

Calculate your absolute risk: Your absolute risk depends on your age and comorbidities. The measured risk for 70-year-old men (not controlling for comorbidities) of developing at least one serious sequelae of medically diagnosed covid n (which means it was serious enough to actually get the patient the doctor) is ~12%. If you want to norm this for your own demographic, you can get a very crude estimate by entering your demographic information in this calculator, dividing your risk of hospitalization by 3 and multiplying the total by 0.4 (which includes the 20% reduction from vaccination and the 50% reduction from Paxlovid). If you are a cis woman, multiply by 2 to account for increased risk (trans people: I have no idea, if you find good data please let me know). 

I cannot emphasize enough how crude this is. I got that 3 by making up a 70 year old man with some common comorbidities, which has a risk of hospitalization of ~36%, and noticed 36/12=3. I don’t think The Economist has been keeping up to date with the latest strains of covid or even the impact of vaccination; these proposed calculations are strictly for order-of-magnitude estimates. 

Sample calculation: a 35 year old woman with no comorbidities shows a 3.8% risk of hospitalization (with their data, which I believe is very old). 3.8%/3= 1.3%. 1.3%*0.4= 0.5%. Times 2 for being female = 1.0%. So a covid infection bad enough to require medical attention has a 1 chance in 100 of a serious persistent issue post-covid. 


Nirmatrelvir and the Risk of Post-Acute Sequelae of COVID-19 (pre-print)

This study compared people who got covid and received Nirmatrelvir (half of Paxlovid). It used data from the American Department of Veteran Affairs, which means the participants are older (average age 65), overwhelmingly male (~90%), and very white (75%). Last time I checked maleness increases the risks of short-term covid consequences but decreases the risks of long term consequences, so good luck balancing that calculation.

The distribution of medication was not random. They don’t specify beyond this, but I assume VA doctors are more likely to aggressively treat patients who are sicker or have more co-morbidities, which should lead the study to understate the impact of treatment. Additionally they were only giving nirmatrelvir, which is one of the two drugs packaged together to make Paxlovid. I’m going to be an optimistic and assume the second drug was included for good reasons, which make this study underrepresent the usefulness of Paxlovid. But they don’t give the dosage at all, so there is a wildcard.

All that said: Nirmatrelvir was quite helpful, cutting the risk of long covid (PASC) at 90 days by ~25%, which in this group translated to 2.5 percentage points. 

Survival here means “survived w/o long covid symptoms”. You might ask why that goes down over time, given some people recover between days 30 and 90. I believe the answer is that they didn’t check for symptoms’ persistence: any diagnosis of long covid issues put participants in the PASC bucket forever.

Effect by symptom:

Long COVID after breakthrough SARS-CoV-2 infection

This is another study with VA data. They compared outcomes of infection after vaccination, compared with vaccinated controls. 

Participants with infections after vaccination (aka breakthrough infections) had a 12 percentage point increase in risk of symptoms in 12 areas, compared to vaccinated people who didn’t get infected. Again, the study population is probably at higher risk than average due to age and associated comorbidities.

However, this risk is heavily concentrated among hospitalized patients:

They also compared the risks to those of infections in unvaccinated people. Vaccination clearly helped, but not by as much as one would hope.

Just for fun, here’s the long-term risks of covid relative to the flu:

Long covid outcomes at one year after mild SARS-CoV-2 infection: nationwide cohort study

This paper looked at long-term health outcomes from an Israeli HMO. It mixed vaccinated and unvaccinated participants but held infection severity constant, which is unforgivable from an absolute risk estimation standpoint but probably fine for looking at the trajectory of recovery from long covid over time. “Mild” appears to mean “did not end up in the hospital”; however the case did need to be serious enough that it made it into medical records in the first place. 

The general trend is “things get better”, with the rate of improvement varying by symptom type. Unfortunately cognitive effects are the slowest to resolve, with at best a 50% recovery rate one year out.

Thanks to anonymous patron for supporting the original research and Patreon patrons for supporting this write-up.

A different observation of Vavilov Day

At this time last year, I was in the middle of a 36 hour fast in honor of Nikolai Vavilov and his team, who starved themselves to preserve a seed bank that went on to dominate Russian agriculture.* One reason I did that was to honor the team and their sacrifices, but another was to test and develop my own ability to do hard things when necessary. It was a great experiment, I did better than I thought I would but also the costs took longer to repay than I thought, and all of that knowledge was really valuable to me.

I went back and forth about doing the fast this year. The sense of continuity and retesting myself felt valuable and I’m sad about missing out on them. But I’m currently doing hard things and my capacity to deal with that kind of pain is a limiting reagent right now. Fasting for Vavilov Day would come at the expense of an actual project that matters to me. Delaying real work for a symbolic sacrifice would not only be stupid, it would be bad symbolism. I can’t honor a sacrifice for a cause by sacrificing a cause for symbolism.

So this year I’m not fasting. I do think I’ll want another fast at some point to see how my medical miracle affected things, but it will wait.

*My one sentence here is already simplified from the story as fully known in the West, read the blog post for more. I also suspect a lot of details haven’t made it into English. Last year I looked into hiring a Russian researcher to investigate and even found someone in mid-Febuary, but they put it off one week for a root canal and then had some other excuse the next week so seems like they’re not going to come through.

Vegan Nutrition Testing Project: Interim Report


Reducing consumption of animal products is a choice with both moral and practical consequences. Last summer I found myself in contact with many vegans who cared a lot about the moral consequences, but had put little effort into learning about or managing the practical consideration of removing animal products from their diet. I’ve suffered a lot due to bad nutrition, so this made me very concerned. With a grant from the Survival and Flourishing Fund, I launched small a pilot project to give nutritional tests to 5 vegans and near-vegans from the Lightcone Office, which they could use to choose supplements that would hopefully improve their health.

My long-term goal was for everyone to have accurate information on their personal nutritional costs of veganism and make informed choices about how to handle them, with the first line solution being supplements. My goal for the pilot was to work out practical issues in testing, narrow the confidence interval on potential impact, and improve the nutrition of the handful of people. This report is on phase 1: getting the testing done and supplements started. It is aimed at people who might want to run a similar program at scale; if you are interested in running this for yourself I recommend checking out Tuesday’s post on iron deficiency.

Tl;dr: I found rampant iron deficiencies, validating the overall concern. The procedure I used has a lot of room for improvement. 

The Experiment

I gave nutrition tests to 6 people in the Lightcone office. 

The ideal subject was completely vegan, had never put any effort or thought into their diet, and was extremely motivated to take a test and implement changes. This person does not volunteer for studies, so I ended up with 4 vegans or near-vegans who had put somewhere between 0 and a lot of thought into their diet, 1 vegetarian, and 1 extremely motivated omnivore I used to test out the process.  In addition, one hardcore vegan contributed results from private testing. I did not poll the ~vegans on their exact diets.

Unless otherwise stated the results exclude the omnivore.

I gave each of these six people a Genova Metabolomix+ test, ordered from, with the iron add-on. This test was selected for being recommended by doctors I trust (in part because they prefer urine to blood testing), having extremely easy-to-read results, being nearly comprehensive (with the unfortunate absence of vitamin D), and because I hoped urine collection at home would be easier than blood draws at a lab. Foreshadowing: I was wrong about that last part.

I also gave people the option of an add-on to determine what variant of the MTHFR gene they have. MTHFR can affect how one processes certain B vitamins, and certain variants can necessitate a more expensive form of supplements.

Several people (although not everyone) scored with undetectably low iron. I offered them follow-up blood tests, which one person accepted. An additional vegan contributed blood test results without urine results.

As of publication all subjects have received their first round of results and started supplements of their choosing. 

The original plan was to retest in 3-6 months after people began supplements, using the same urine tests.

My initial predictions

I expected the big shortages to be B12, iron, and vitamin D, the first of which has very few* natural vegan sources and the latter two of which are scarce, although not absent, in vegan sources. This makes it pretty unfortunate the original test did not include vitamin D. 

[*B12 is naturally found in some (but not all) seaweeds and algaes, in at least one kind of mushroom, and in nutritional yeast. It’s also added to many wheat products in the US, so if you eat enough wheat and aren’t going out of your way to get unfortified wheat that’s a strong source]

Relative to the mainstream I wasn’t very concerned about protein consumption. Vegan proteins are a little less abundant, a little harder to digest, and have a less ideal distribution of amino acids, but are basically fine as long as you don’t pile on additional constraints.

One reason I was concerned was that lots of people I polled were piling on additional constraints, like keto or gluten-free, and still not doing anything to manage nutrition. I expected a smattering of deficiencies from these people, and to a lesser extent from everyone, as their restrictions and tastes cut off random nutrients. These could have been in any almost nutrient.

I expected everyone to be fine on vitamin C because it is abundant in both produce and processed food (where it’s used as a preservative).


(including only vegans and near-vegans)

  1. ¾  vegan testers had severe iron deficiencies in their urine tests.
    1. The one who didn’t had both a stunning dietary intake of iron, and a parent who 23andMe believes to have a genetic predisposition to excessive absorption of iron.
    2. An additional vegetarian tester was not deficient.
    3. One of these retested with a blood test and scored low normal (~30). However this person was already taking iron supplements at the time of the test. 
    4. A bonus blood-only participant tested between 13 and 20, meaning they’d be considered deficient by some standards but not others.
  2. There were no B12 deficiencies, probably because everyone was already on B12 supplements. 
  3. One tester had a lot of deficiencies, including vitamin C, to the point I suspect it’s a problem with digestion rather than diet. 
  4. Everyone had at least one amino acid deficiency, including the person eating over 100g of protein/day. I don’t know how big a deal this actually is.
  5. The urine test did not include vitamin D.  Of the 2 blood tests, both had low-normal vitamin D.
  6. Excluding the person with across-the-board deficiencies, there were scattered other deficiencies but nothing else to consistently worry about. People were mostly in their tests’ green zone, with occasional yellow and red.

What does this mean?

Only one near-vegan out of 5 had solidly good ferritin levels. As I discuss here, that’s a very big deal, potentially costing them half a standard deviation on multiple cognitive metrics. 

There’s no control group, so I can’t prove that this is a veganism problem. But I’m quite suspicious.

There were no other consistent problems, so broad-spectrum testing is probably overkill for people with no known problems. 

Retrospective on the project

What worked

I consider the core loop of the study as vindicated as can it be at this stage. 

  • Deficiencies were identified, and the primary one was one of the three I predicted.
    • And another of the three, B12, was probably absent because people treated it preemptively. Note that people were inconsistent in what they took so I can’t say definitively what they were on during testing.
  • In the counterfactual timeline the shortages were probably identified much later if at all. No one who participated had any plans for testing, including people with obvious symptoms and people whose doctors had previously recommended testing.

This will be less impressive if supplementation doesn’t turn out to fix anything, but it’s an extremely solid start.

Other things that went well:

  • Having the room in my budget for unplanned additional testing, so I could add in serum iron tests when it became obvious they were necessary.
  • Creating a shopping list with links. I was worried this was somehow taking advantage of people (since I used affiliate links), but removing a decision and several steps from the ordering process seems to have been pretty crucial. 
  • Bypassing the need for doctors’ visits to get a test. Given how long it took people to order tests I think doctors’ appointments would have killed the project entirely. 
  • The Lightcone ops team was extremely cooperative and got all of the vitamins I suggested into the office.

Difficulties + possible changes

Potential changes are framed as recommendations because I am deeply hoping to hand off this project to animal advocates, who caused the veganism in the first place. 

  1. The test ordering workaround was not as good as I had hoped
    1. I’d originally hoped to just hand participants a box, but they had to order the tests themselves.
    2. In order to get iron + genetics tests people had to call rather than order online. This is non-standard for the provider and two people had to call twice to insist on what they wanted.
    3. Tests took a long time to ship, and a long time to return results after shipping. The lab alleges this is a supply chain issue and there’s nothing to be done about it. 
    4. Those two together turned into a pretty big deal because they made it very hard to plan and people lost momentum.
    5. In combination with the results showing few problems beyond iron I recommend deemphasizing full spectrum urine tests and focusing on blood tests for iron (and vitamin D), and making those convenient, perhaps by bringing a phlebotomist to the office.
    6. Another option would be to bring in a medical practitioner, who can order tests for other people, to manage tests so the office can be stocked with them. This of course fails to solve the problem for anyone not in the office.
    7. There are home tests for vitamin D and iron specifically, but I have no idea if they’re any good.
  2. Ideal test subjects (completely vegan, never done nutritional testing or interventions, promptly puts in the effort to do these tests and act on them once I suggest it) were even thinner on the ground than anticipated.
    1. I knew there wouldn’t be many, but I didn’t think it would be so hard to get five people pretty close to that profile. 
    2. I loosened restrictions and still consistently found problems, so recommend lowering the eligibility bar for testing in future rounds, especially since that was always the plan. The strict requirements in this round were an attempt to make the signal as loud as possible.
  3. Getting everyone tested was like herding cats. Beyond the problems with the test distributor, some participants needed repeated reminders to order, one lost a test, results went missing… it was kind of a nightmare.
    1. One advantage of focusing on blood tests would be to cut down on this, especially if you bring the phlebotomist to the office.
  4. At points I was uncomfortable with the deference some participants showed me. I was as clear as I possibly could be that this was a best-effort from a knowledgeable amateur kind of thing; they were responsible for their own health and I was a nonexpert trying to provide some logistics help. I nonetheless got more than one person bringing me problems not even related to the nutrition project, and insisting I tell them what to do.
    1. Recommendation: bring in a skilled nutritionist. They can both give better advice than me and devote more time to helping people. 
  5. I initially misread the protein results (which are delivered in terms of “how deficient are you?” rather than “what’s your current level?”, making 0 the best possible score). Luckily I knew I was confused from the beginning and no one had taken any actions based on my misinterpretation. More broadly, I’m just a woman who’s had some problems and read some stuff, I expect my suggestions to be better than nothing but far from the maximum good it would be possible to do.
    1. Recommendation: bring in a skilled nutritionist
  6. I underestimated the amount of time and especially emotional labor this project would need. I was hoping to bluff my way through that until people got on supplements, at which point the improvements in health would be their own motivation. I think I always overestimated how well that would work, but it was especially wrong because all the problems with the tests drained people’s momentum.
    1. Recommendation: I still think you should bring in a skilled nutritionist
  7. Many of the participants were moving frequently and not in the office by the time their results came in (because they took so long…), so they had to buy supplements themselves. Given the option I would have selected people consistently in the office, but as mentioned I was already managing trade-offs around participants.
    1. Recommendation: ask for more money to give everyone their first month of supplements and a convenient pill planner.

Next Steps

I previously planned to give people the same urine test 3-6 months after they started supplements. That no longer seems worth it, relative to the cheaper and more convenient blood tests. 

It’s not actually clear a formal follow-up is that useful at all. I initially planned that because I expected a wide range of shortages such that literature reviews wouldn’t be helpful. But there was only one real problem, and it has a richer literature than almost any micronutrient. So I don’t think another 5 people’s worth of scattered data is going to add much information. 

So the next step for this as a project would be mass blood testing for B12, iron, and vitamin D. 

Feeling motivated?

If this has inspired you to test your own nutrition, I haven’t done anything you can’t do yourself. Both the urine and blood tests are available at, and if you have a doctor they’re quite likely to agree to testing, especially if you’re restricting meat products or fatigued. I have a draft guide of wisdom on supplementation I’ve picked up over the years here, although again, I’m not a doctor and only learned how to digest food last May, so use at your own risk. 

Thank you to the Survival and Flourishing Fund for funding this project, Lightcone for hosting, and all the participants for their precious bodily fluids.

Iron deficiencies are very bad and you should treat them

In brief

Recently I became interested in what kind of costs were inflicted by iron deficiency,  so I looked up studies until I got tired. This was not an exhaustive search, but the results are so striking that even with wide error bars I found them compelling. So compelling I wrote up a post with an algorithm for treating iron deficiency while minimizing the chance of poisoning yourself. I’ve put the algorithm and a summary of potential gains first to get your attention, but if you’re considering acting on this I strongly encourage you to continue reading to the rest of the post where I provide the evidence for my beliefs.

Tl;dr: If you are vegan or menstruate regularly, there’s a 10-50% chance you are iron deficient. Excess iron is dangerous so you shouldn’t supplement blindly, but deficiency is easy and cheap to diagnose with a common blood test. If you are deficient, iron supplementation is also easy and cheap and could give you a half standard deviation boost on multiple cognitive metrics (plus any exercise will be more effective). Due to the many uses of iron in the body, I expect moderate improvements in many areas, although how much and where will vary by person. 

Note that I’m not a doctor and even if I was there isn’t good data on this, so it’s all pretty fuzzy. The following is an algorithm for treating iron deficiency that I’ve kludged together from various doctors. I strongly believe it is a lot better than nothing on average, but individuals vary a lot and you might be unlucky. 

  1. Take a serum ferritin test. If you have a doctor they will almost certainly say yes to a request, or you can order for yourself at
  2. If your results show a deficiency (<20ug/L), increase iron intake through diet or supplements such as Ferrochel, taking the default dose once per day, with a meal.
    1. The definition of deficiency can vary by study, lab and goal. I picked <20ug/L because it’s the highest level I have concrete evidence is insufficient, but personally believe people are likely to benefit from iron beyond that and am taking pills accordingly.
  3. If you experience negative effects after taking the pills, stop immediately. Give yourself a week to recover, then you can try other brands, be more careful to eat with a full meal, etc. 
  4. If you are experiencing the symptoms of iron poisoning (listed below), stop pills and see a doctor now. Iron poisoning is a very big deal, which is why step 1 of this algorithm is “get tested” not “gobble pills”.  Unfortunately several of these are pretty generic, but I’m never going to feel bad about telling people with seizures to seak medical attention:
    1. Nausea
    2. Vomiting
    3. Abdominal pain
    4. Dizziness
    5. Low blood pressure and a fast or weak pulse
    6. Headache
    7. Fever
    8. Shortness of breath and fluid in the lungs
    9. Grayish or bluish color in the skin
    10. Jaundice (yellowing of the skin due to liver damage)
    11. Seizures
    12. Black or bloody stools
  5. Retest at 8-12 weeks, ideally at the same lab as before.
  6. Continue to retest every 8-12 weeks.
  7. If you increase by 20ug from your starting value without noticing any improvements to your cognition or overall energy levels; low ferritin is probably not your bottleneck.
    1. If you believe it’s not a problem at all, quit.
    2. If you believe it is a problem but another problem is limiting your gains, stay on a maintenance dosage but don’t put more time into managing this. Verrrrry roughly, divide your current dosage by your currently monthly gains (so If you take one RDA/day and gain 10ug/month, your result is 0.1), and take that much. This hopefully keeps you from losing ground, without gaining so quickly it could become a problem.
  8. If you’re getting improvements, keep going until those taper off. I personally would exercise caution and investigate the downsides of iron once I reached 80ug/L, but I’ve never gotten close to that so it hasn’t come up. 
  9. Continue to retest and adjust until you’ve found a dose on which your values are stable and healthy.

[Note: I provided links to supplements because I found people follow through more when I do, and because it’s easy to buy worthless supplements. There are other good supplements out there and if you have a reason to prefer one, take that instead. Links are affiliate.]

Research summary

Iron’s most famous use in the body is in hemoglobin, which your blood uses to transport oxygen. Oxygen is extremely important [citation needed], so it makes sense that low hemoglobin (aka anemia) gets a lot of attention, and everyone agrees anemia is very bad. But what the studies I read found was that even among people who started with adequate hemoglobin, a low ferritin score still predicted they would benefit from supplementation. And it’s not because of a bad definition of “adequate”; people saw benefits even when their hemoglobin didn’t change. So what else does iron do? 

Iron is one of a small number of elements that can safely accept electrons in reduction-oxidation reactions. Free electrons are quite damaging, so iron’s ability to safely contain them is important. Some specific usages:

  • The enzyme catalase, which converts caustic H2O2 to harmless water.
    • Fun fact: Catalase is the least important enzyme whose name and purpose I can recall offhand. Other enzymes achieved that status by being very important (DNA polymerase), or having self explanatory names (carbohydrase), but catalase achieved this by sounding kind of similar to a song I was into the summer I took microbiology, and I made up alternate lyrics about the enzyme.
  • Multiple points in DNA synthesis and repair, including keeping DNA polymerases in their correct shapes.
  • Myoglobin: similar to hemoglobin it binds oxygen, but instead of blood it stays in muscles, holding oxygen in reserve until it is needed.
  • Regulation of many components of the immune system.
  • Proline and lysyl hydroxylases, both used to build collagen.
  • Please enjoy this list of 80 enzymes that use iron as a cofactor.

I’d say “that’s a lot” but honestly it’s not, everything in the body is like this, it was not built to be understood.

Standard tests for anemia only look at hemoglobin. Ferritin tests are considered to be a much better measurement of cellular iron levels. There’s suspicion, although not proof, that your body prioritizes hemoglobin production above other uses of iron, so it will undersupply these other uses in order to maintain hemoglobin levels. This suggests that if you have normal hemoglobin but low ferritin, additional iron will find many uses. Unfortunately, those uses and their effects are so varied I can’t really predict what any particular person will experience.

There are any number of studies showing correlations between low ferritin and low functioning, but I don’t find those very useful. The people in those studies might have any number of deficiencies for multiple reasons, or low ferritin levels could just be a proxy for poverty. In my research I stuck to actual experiments, with controls, that gave iron to subjects and checked for an improvement in function, not just test scores. Unfortunately, there were not that many of them.

The only study I liked on the cognitive effects found an absolutely enormous effect. Successful iron supplementation led to improvements averaging >0.5 standard deviations in attention, learning, and memory. I have qualms about this study and expect the results are cherrypicked, but it’s also not necessarily the full size of the effect, because they stopped after a set amount of time rather than waiting for effects to plateau.

There were multiple studies on iron supplementation and exercise. In a nutshell: everyone’s endurance improves when they exercise. Giving people with iron deficiency but not anemia (IDNA) iron supplements increases that effect. In the strongest study, people treated for iron deficiency for 6 weeks improved their 15km time by 10%, compared to 5% in the control group. Another study (which didn’t involve exercise training) showed no improvement in time to complete a given distance, but did find the treatment group used about 5% less energy while doing so. 

Iron deficiency rates vary a lot by population, but with the patterns you’d expect. Vegans are more deficient than vegetarians, who are more deficient than omnivores. People who regularly menstruate (or give blood) are more likely to be deficient. I found the baseline rate of omnivorous men in rich countries to be somewhere between 0-11%. For a female omnivore it’s 9-22% (these numbers include people already taking supplements; it’s presumably higher if you don’t). Young female vegans who were not already supplementing were at least 50% deficient, plausibly more. Data for non-supplementing male vegans was not available, but let’s ballpark it at 5-25%, based on the ratio between men and women in the general public.

People in poor countries are much more likely to be iron deficient and anemic, due to poor diet and more physical exertion. 


I am not a doctor, my most relevant credential is a BA in a different part of biology, the fact that I couldn’t find a decent resource and had to make it myself is a sign of civilizational inadequacy.

Normally not being a doctor inhibits me from giving medical advice, but I am going to go ahead and say that iron poisoning is extremely bad and not that hard to induce with pills, don’t do that. Iron poisoning is why you need to be careful your kid only gets one multivitamin a day, and why men can’t use women’s multivitamins (which should actually be “menstruator’s multivitamins”, since the relevant issue is monthly blood loss). 

The papers are very finicky and boring and this was really important, so I’ve tried to frontload my conclusion. This is a delicate balancing act of readability and accuracy. I did my best but some trade-offs are unavoidable. 

This lit review was done with a focus on people with low iron intake, especially vegans. None of the studies I looked at filtered on dietary intake versus absorption issues. This means they probably underestimate the impact of supplementing for healthy people.

Do not take the dosages in the studies literally, especially if you don’t menstruate. The right dosage depends on the form and your personal needs. I suggest operating based on RDA percentages rather than raw chemical weights.



There are a lot of ways to measure iron and iron-related levels in the body. The two most important are hemoglobin (the protein red blood cells use to carry oxygen) and ferritin (the protein your cells use to store oxygen, but also present in blood). There are some other numbers I’m going to ignore.

Hemoglobin and ferritin are both testable via blood sample, and the tests have something called “reference ranges”, which are supposed to be the healthy range of values. Whether the ranges actually capture that is a matter of great controversy, with various people alleging the minimum is what you need to avoid hardcore deficiency diseases, but won’t get you optimum functioning, to people claiming low scores are fine and anyone who says otherwise is a psyop from Big Vitamin. And then there’s individual variation.

Hemoglobin’s reference range is 120g/L-170g/L.  Ferritin’s reference range starts between 10 and 20 ug/L, and ends at 150-200ug/L, depending on who you ask.  It’s possible to have low hemoglobin (aka anemia) without an iron deficiency or vice versa. Low hemoglobin with adequate iron typically means you’re having trouble manufacturing hemoglobin and is beyond the scope of this post. Low iron with adequate hemoglobin is more controversial. Top explanations include “the tests aren’t that good”, “you’re deficient but your body is prioritizing hemoglobin production”, “you’re about to develop anemia” and “low iron is fine, actually”.  

Impact Data

When looking at studies I used the following selection criteria:

  • Examining iron deficiency without anemia. We can assume that anemic cases will benefit more from iron, unless the anemia is unrelated to the iron deficiency.
  • No co-morbidities.
  • On adult humans (in practice this almost always means women).
  • In the developed world.
  • RCTs only, no correlational studies.

This didn’t leave a lot of studies, and I had to accept some other flaws. 


Murray-Kolb and Beard (2007)

This study was by far the best study of cognitive function, maybe the only one that tested an intervention rather than merely looking at correlations. I don’t love it. The data presentation is obviously leaving a lot of information out, I assume to dramatize results. But those results are very dramatic. 

This study allowed for mild anemia (hb < 120 but >105), but separated anemic and non-anemic subjects. The paper, uh, doesn’t mention its threshold for iron deficiency; another paper from the same authors set it at serum ferritin <=12ug/L, which is in line with the aggregated averages.

The study included a double control group that started with sufficient iron and hemoglobin. Each group (no deficiency (n=42), iron deficiency without anemia (n=73), and iron deficiency with anemia (n=34)) was split into treatment and placebo groups. 

Iron supplementation increased ferritin levels in everyone. People with iron deficiency without anemia (IDNA) increased serum ferritin (sFt in the table) 2.5x more than their placebo group; people with iron deficiency and anemia (IDA) improved ferritin levels almost 4x more than their placebos. Neither group got anywhere close to the ferritin levels of the no-deficiencies group. The treatment group was given 160 mg of ferrous iron daily.

In baseline cognitive testing, IDNA women scored about the same or slightly worse as healthy women, and IDA women scored much worse than both. This is probably an underestimate of the effect, because the study was heavily recruited from students at a single university, who can be expected to be selected for the same range of competence.

The study separately evaluated treatment-group women who had increased ferritin levels from those who didn’t. The former group had large improvements in their cognitive test results, the latter very modest ones. I think separating out non-responders is fair: if there’s a problem interfering with iron absorption that doesn’t tell you anything about the effect of increasing ferritin levels, and I am studying this mostly for the benefit of people with insufficient dietary intake.

Among ferritin responders, attention, memory, and learning increased from .5 to .75 standard deviations (although somehow that .75 is at p<0.07). That effect size is the equivalent of 7.5-12.5 IQ points or 1.1-1.6 inches in height. Of course the test could be bullshit, but it’s not out of line with anecdotes I hear. Additionally, the treatment groups did not reach the ferritin levels of the healthy group, indicating potentially more gains to be had.

Hemoglobin responders also saw more improvement than non-responders, but the effect size was smaller than with ferritin, indicating an effect of iron beyond increasing hemoglobin.

(Note that the axis has changed from performance to time required, making negatives good. Yes, I am suspicious that they presented total score for one metric and time to completion for another).


Zhu and Haas (1998)

20 women with normal hemoglobin (Hb >120 g/l) but low ferritin (serum ferritin <= 16 ug/l) were given 135 mg ferrous iron supplements for eight weeks and instructed to take with citrus juice. 17 women were given placebos as a control (random assignment, double-blinded). They were given both blood and athletic tests before and after treatment.

Treatment group hemoglobin and iron binding capacity were unchanged. Serum ferritin was up 250% for the treatment group (compared to 30% for the control). Their athletic test results did not improve any faster than the controls, however they needed less energy (2.0kj/min) and oxygen (5%) to get those same results. 

Hinton et al (2000)

22 women with normal hemoglobin (Hb >12 g/dl) but low ferritin (serum ferritin <= 16 ug/l) were given 100mg ferrous iron supplements for six weeks. 20 women were given placebos as a control (random assignment, double-blinded). They were given both blood and athletic tests before and after treatment.

Iron supplementation did not change hemoglobin or iron binding capacity levels, but did increase serum ferritin by about 50%, and transferrin saturation by 70%. Note that their ending ferritin levels (19.4) were still barely above the bottom of the reference range, indicating there was probably much more room for growth. 

The control group went marginally up on some measurements and marginally down on others, I’ve treated their changes as noise.

Both treatment and placebo groups were given 4 weeks of exercise treatment; the treatment group showed about double the athletic improvement. Endurance saw a bigger improvement than initial performance.

Brownlie et all (2004)

~20 women, with serum ferritin concentration < 16 ug/L and a hemoglobin concentration > 120 g/L were given 100mg ferrous iron/day for 6 weeks. Of that, 4 weeks also included exercise training.

Once again we see an improvement in ferritin but not hemoglobin or binding capacity.

The treatment group experienced ~30% more improvement in their trial times than the control, or 800% if they started with elevated ferritin. I’m suspicious of this posthoc subgroup analysis, but on the other hand, the bar in this graph is very big.

Hinton and Sinclair (2006)

The good news: this study has men! I did not think I was going to find any of those!

The bad news: this study has 20 people, total.

No meaningful change in hemoglobin or binding capacity, near doubling of serum ferritin in the treatment group, 15% drop in ferritin in the control group. 

Results are basically identical for the control and placebo groups.

Prevalence Data

Estimates for the prevalence of iron deficiency vary a lot by study and population. 

In the first paper I found, the estimate was 9-22% among menstruating women in the general public, and 1-2% among adult men (non-menstruating women were not included but I expect “do you lose 2-4 tablespoons of blood every month?” and “do you occasionally host demanding parasites?” to be more important than hormones or gender identification). Note that this number includes both anemic and non-anemic iron deficiency. 

Vegans are at much more risk. One German study of vegan women found a median serum ferritin level of 14 ug/L, a level that is above their reference range and LabCorp’s but below the cut-off in several of the studies cited above. They found 40% of young women fell below their threshold for deficiency (12ng/ml) and 11% of older women (presumably mostly post-menopausal) did so. Women taking iron supplements were excluded from this study.

A second German study (why are they all from Germany?) that allowed supplements and had an even gender split found rates of iron deficiency slightly lower in vegans than omnivores, but both had higher means than anyone in any of the impact studies I found. Nonetheless, 10% of vegans were iron deficient.

My own study (data forthcoming) had 3-4 male vegans and a deficiency rate of 25%-75%, depending on how you count. 

Thank you Survival and Flourishing Fund for funding this research and Lightcone Infrastructure for providing a home for it.

Thanks to Andrew Rettek for help making my normally very in-the-weeds style more accessible.

Quick look: cognitive damage from well-administered anesthesia 

Recently a client commissioned me to look at the potential cognitive impacts of general anesthesia. I was surprised to find out that it’s not obvious general anesthesia does more damage than spinal or local anesthesia, and my guess is most but not all of the damage is done by the illness or surgery themselves. 

Caveats and difficulties

I’m not a doctor. The following represents something like 5 hours of work, which obviously is not enough time to process even a fraction of the literature. I was focused on the dangers of median uses of anesthesia, where nothing goes obviously wrong and the anesthesiologist considers it a success; I didn’t even attempt to look at the rate of accidents, which can be pretty severe. My friend’s dad’s life was ruined by a fungal contaminant in a spinal injection. And of course, people die from excess general anesthesia. But for this post I only looked at damage done by routine anesthetic usage.

Like all client research, this was tailored to a particular person’s needs and budget, and shouldn’t be considered a general-purpose survey.

It’s pretty hard to tease out the difference between damage done by anesthesia, damage done by whatever necessitated the surgery, and damage done by having your body ripped open and bits moved around. Bodies hate that sort of thing. The few RCTs that exist by necessity focus on a narrow range of minimally invasive surgeries for which there exists a choice in type of anesthesia, and animal studies tended to focus on developing animals rather than adults. Even for procedures where multiple types are possible, patients tend to be pretty opinionated about what they want; one paper even announced they’d given up on reaching their sample size goal because recruiting was too hard.

Studies also often focused on cognition within a few hours of surgery (when people are still at the hospital to test). I think that’s less likely to be “damage” and more likely to be “it’s still wearing off” or “I’m sorry, I just had minor surgery and you want me to take an IQ test?”. This made me throw out a lot of studies.

Few if any of the papers attempted to control for post-operative condition or pain med usage, which seems like an enormous oversight to me.


My overall take home is that:

  • Little or nothing that necessitates surgery is good for cognition and that needs to be factored into assessments.
  • Surgery itself is enormously stressful, physically and emotionally, and that stress impairs cognition, sometimes in lasting ways. This includes procedures that are not cutting new holes in you, like kidney stone treatments, although presumably it’s worse for open heart surgery.
  • Probably there are additional effects from anesthesia. At least general and spinal, maybe including local. On priors I still believe general and spinal are worse on a purely physical level.
  • Probably a lot of whatever damage there is heals in most people, although people who need surgery are already under heavy load and will be the worst at healing. 
  • There may be treatments that can prevent damage but they’re still in rodent trials right now.
  • I also believe that being awake and aware during surgery can be emotionally traumatic, and trauma is also bad for cognition, so include that in your math. 
    • But I’m not trustworthy on this, seeing as I was terrorized by a series of dentists and now can’t get myself through simple teeth cleaning without some sort of bribe, a human to guard me from the bad dentist monster, and a sedative. 


I didn’t rigorously track correlational studies, but my sense was they tended to show faster recovery from local and spinal anesthetic, relative to general, presumably because milder cases get milder anesthesia even when the procedures use the same billing code. Additionally a lot of studies were given too soon after surgery, which I don’t expect to predict long term damage

In the few studies that randomly assigned patients to spinal, local, or general anesthesia, and surveyed at least 7 days out, it’s really hard to pick a winner. 

Incidence of postoperative cognitive dysfunction after general or spinal anaesthesia for extracorporeal shock wave lithotripsy tries really hard to claim that spinal and general anesthetic are equally damaging to cognition, despite finding a 3x higher rate of cognitive issues after general anesthestic. I showed this paper to my statistician father and he gave a rant I wish I had recorded because it would make me famous in the right corner of Twitter. Hell hath no fury like a statistician forced to read a medical paper. He agreed with me that 19.6% (the rate of complications in the spinal group) was much larger than 6.8% (rate of complications in the general group), but dismissed that as merely a felony next to the war crimes against statistics they committed by using the wrong test for statistical significance.

Two meta-analyses both find a small difference in favor of spinal over general, with confidence intervals that overlap no-difference. One found spinal to be ~5% better (26 studies), the other 50% (but only 5 studies, so still overlapping with 0). The latter analysis is tiny in part because it is restricted to tests within a week of surgery. The analysis that looked also failed to find improvements from using local anesthetic.

On the other hand, animal studies of anesthesia without surgery regularly show impairment, although they can’t agree if post-anesthesia animals start off worse but catch up, or start off the same but fall behind. Also they found other medications could mediate the effects. I summarize the animal results in this spreadsheet. These are effect sizes we would clearly notice in humans so I assume they’re using much more anesthetic (although they claim it’s proportionate) or the animals, primarily rodents, are much more sensitive. Also the studies tended to be within days of anesthesia application, removing a chance to heal.


The original commission was to investigate kidney stone treatments, and what I can say there is that the general medical site UpToDate is pretty good. Every claim I investigated checked out and I didn’t find anything at all established that they didn’t.

Thank you to Claire Zabel for commissioning the research and encouraging me to share the findings, and to my Patreon patrons for supporting the public write-up.