I fully agree with all of the above. From the first message of this thread I noted that I agreed with the cruxes of the post. I agree that N, M, and P are important and we should gather & disseminate better information on them.

To my understanding, in futher posts we've been discussing how much the trade-offs matter, to what extent they've been suppressed, and whether some sub-fields have trade-offs at all (e.g. leather).

I don't think it's possible to have a discussion without any shadow of Q, because ultimately without Q there's not even a discussion (beyond a 1-page of current research on one lifestyle choice among many). Your "why is this so hard to talk about" section is answered mostly with Q itself. 

That being said, I should have worked harder to stay on topic. I apologize if my replies here have been unhelpful to this discussion. 

At the very least, I am still thankful for your thoughtful responses, as I have found this thread both interesting and useful.

You're absolutely correct on the details. Most people going SAD -> vegan increase health, because they generally trade cost or convenience.^[1]

Most people^[2] wouldn't pay $N or $M for P without Q, as most people who don't value Q don't make the trade. I would not expect any completely amoral Americans to be vegan. My veganism is an argument based on Q, not for the irrelevance of N/M or the magnitude of P. I would expect both N & M to decrease as percent vegans in the local population increase.

However, while vegan being > SAD on health (even without mentioning N/M) is not relevant to this discussion, correctly saying "hey a balanced vegan diet won't make you waste away" is still shocking news to many people. Therefore noting that there is a P is very useful with many non-vegans. If any EA people think there is no N/M, I think this is possibly the only U.S. subculture where that's true.^[3]

Also, to take a step toward the meta: "good health" and "animal suffering" are [sometimes] sacred values, where time/$ aren't. So for whom those are sacred values, this is noting that you can have both sacred values by trading against only non-sacred values. Hopefully this is irrelevant to EA/LW people, but it is extremely relevant in the "real world".

1. ^{^}

   In wealthy urban areas with higher % vegans, the trade-off is usually cost (eating out at vegan restaurants, etc.). In areas that are small with few vegans, the trade-off is convenience (I started cooking more; there is only one vegan restaurant near me that is too far & expensive to regularly visit).

2. ^{^}

   In regular meat-heavy U.S. culture. YMMV in specific subcultures.

3. ^{^}

   Sorry for my clumsy wording & many footnotes. What I'm trying to say is that in the equation where you trade $N and $M for P and Q, I think people (outside maybe EA) systematically overcalculate N and M and undercalculate P, even before accounting for Q, since they think being vegan is harder than it actually is and leads to a negative P value, which is usually false.

   I still don't think they'd make the trade without Q, but in an effort to "counter-balance" Q people seem to (unconsciously?) distort N, M, and P.

It is funny^[1] how long the post ended up & how much we've all ended up debating in the comments, given that I am in 100% agreement with the two-sentence summary and all three footnotes.

1. ^{^}

   Not blaming you, of course. Just observing

First off, thank you for your thorough & thoughtful replies (as well as the thorough & thoughtful original post). I appreciate you using your time to improve the quality of the conversation on veganism.

I agree it's possible that small amounts of high-quality animal products provide minor benefits to people heavily optimizing for health who are otherwise capable of being healthy on a plant-based diet. I just think that 1) very few people are optimizing hard enough for this to matter, and 2) [in people that could be healthy vegans] the value of the mild health benefit is less than the ethical value of preventing the required animal suffering, even if they are being consistent by buying small amounts of extremely expensive high-quality meat.

People for whom iron supplements / heme iron in plant-based meat doesn't help (& would be anemic on any plant-based diet) seem like the kind of people who have obvious and justifiable health-based reason for eating meat. In footnote 1 I was thinking of people who hadn't tried a supplement.

(Also, this is obviously the type of discussion I'd only have in venues like this forum. If a friend says "I have to eat meat because I'm anemic," I don't say "Are you sure??? Have you really tried multiple vegan supplements???" I just say "Dang, that sucks, hope you feel better.")

IIUC you want to allow vegans to be imperfect (with the acceptable bar raising with wealth), but are pretty worried about free riders saying "yay animals! I'm a vegan!" while not actually doing much that actually matters.

This is an accurate description. The details are obviously harder to hammer out.

I would make E being the ethical cost of animal products, s.t. one should go vegan iff N < M*(health costs of meat) + M*E. 

Ideally going vegan keeps you in good health. For many on the SAD, I think a vegan diet will improve health. However, if veganism is going to cause death/disability, avoid it.^[1][2] If it's going to keep you in good health but keep you slightly short of technically optimal functioning, I think the ethical benefits are enough for veganism to still be worth it.

I'm not entirely sure what you mean by "looking for improvements on the margin" before recommending veganism — do you mean health improvements? I'd prefer people default to the maximally-ethical diet and then only introduce animal products as really needed for health, not default to eating animals and then only test out veganism after being super-duper sure they can't eke out a few % increase using offal.^[3]

As far as amelitarianism — I'm sure there are indeed plenty of people who'd find amelitarianism easier, and I'm under no illusion that they care about my personal opinions.^[4] They don't affect my morale, and I prefer amelitarians to standard omnivores. I would only take issue if they call themselves vegan, as then (in aggregate) it affects the meaning of the word, my ability to get (actually) vegan food, etc.

For the record, I hope I haven't come off as too critical; I think we largely agree.

I am very in favor of gathering more empirical evidence on veganism. I think it helps everyone, very much including vegans; a rising tide lifts all boats, etc.^[5][6]

I think testing people's vitamin levels is good, both in giving us community information, and in helping those individuals avoid deficiency. Telling people who somehow missed the memo about B12 supplementation is very good; I'd strongly prefer people not give themselves permanent nerve damage.

Some of your writing feels concern-troll-ish at first pass, but a) I'm not the tone police, b) I think your research is beneficial, and c) there's a reasonable chance I'm just oversensitized by how often I bump into actual concern trolls.

I think our only real disagreement is how much animal suffering matters compared to minor human health benefits (in the population of people who could be healthy plant-based^[7]).

1. ^{^}

   My hot political take is that I quite like humans, and would prefer humans not suffer/die. I would also prefer animals not suffer. I think these can usually be resolved with minimal conflict, but unfortunately not always. What are the odds I convince lots of non-vegans to get their animal-eating needs in the form of stationary bivalves and/or roadkill? :P

2. ^{^}

   Again, both in the "literally cannot process vegan supplements correctly" way and the "extenuating circumstances" way. I mention SPD in a previous-post footnote. I also would be uncomfortable talking about veganism with someone with a history of eating disorders, for example.

3. ^{^}

   Actually I'm not sure what the offal footnote means in general. I hope I've accurately conveyed that "tasting" animals is not the problem. Though offal pills might be more ethical if they're low-cost byproducts? Or maybe you're saying sticking to offal-only decreases the chance of eating unnecessary animal products?

4. ^{^}

   I read Ozy's post a while back and have never commented on amelitarianism before. I only gave an opinion on amelitarianism here because you specifically brought it up in a reply to me.

5. ^{^}

   I'm sure the link was for illustrative purposes, but just to be clear, I'm not the linked LW commenter, nor am I opposed to you conducting research.

6. ^{^}

   Also, completely selfishly, I'd prefer vegans not Streisand effect the real but (IMO) manageable convenience costs of being vegan, at least for those of us in very-omnivorous communities. [Maybe there are no convenience costs for people in wealthy coastal cities with high vegan populations and multiple vegan friends, but if so I can't relate.]

7. ^{^}

   Which I estimated at >=80% if ignoring financial constraints, but I'm very open to both research into what this percent actually is and (ideally) nutrition/agriculture/etc research on ways to raise it.

I'm a little jealous of the "minimal costs of any kind" bit, though I'm also very glad it's worked out that well for you! :-)

The only costs for me have been convenience (I don't have any vegan/vegetarian/etc family or close friends, and where I live there are few to no vegan options at most venues). For example, I went to a friend's wedding recently, and spent ~9 hours at the event with nothing to eat, which was mildly inconvenient. This was totally doable (I pre-ate because I guessed this would be the case, and if I had ex. unsteady blood sugar I would've just packed myself a couple snacks).

I think the vast majority of people can be vegan at low cost & high taste & high health, but for some of us it's more inconvenient than for others.

I take issue with the way you respond to the first quote; I think the way it's written would likely give a newcomer to the discussion wildly incorrect assumptions about what I'm saying.^[1]

I would consider my definition of veganism the "correct" one, as the practicality limit is baked into the official Vegan Society definition of veganism. But I think there are good reasons discussion in wealthy countries de-emphasizes the practicality limits.

Particularly, veganism seems susceptible to a lot of free riders that dilute the language and [arguably] make the movement weaker. I think the number of people that actually need to eat meat/eggs/whatever in the first world is much lower than the number of people that think they need to, and it feels like the way you swapped out my first quote & responded to it encourages the second group to free-ride without critically examining their own habits. [This is not at all meant as a personal criticism, just an explanation of my thought process.]

I'm using emotional language because this is obviously subjective, but I am assuming good faith and doing my best to articulate why the way you responded would make me feel like we're on different "sides" if we were discussing this IRL. I would happily accept impoverished subsistence farmers who eat their cattle as vegan^[2], but I have a hard-earned inherent suspicion of wealthy^[3] people who eat multiple eggs for breakfast every morning because they "need" to. Neither are plant-based, but the "impossible to abstain from animal foods" bar is much higher for the average person in a developed country.

Honestly, in my first bullet point, the word "vegan" would be better replaced by "plant based". Mea culpa.

[EDIT: The (unsupplemented) diet most humans are best adapted to may be mostly plants with some animal protein, but I am strongly against labelling that the unqualified "optimal" diet, for multiple reasons. 

While I agree with your cruxes that not every person is physically capable of being 100% plant-based, I think most people would be more healthy on a decent plant-based diet than on the SAD, and given its ethical benefits I'd say fully plant-based is the "optimal" diet for anyone without very strong health/poverty reasons that make it undoable.]

--

I prefer amelitarians to generic omnivores for logical suffering-reduction reasons, as long as they don't dilute the definition of vegan. Though obviously I think it'd be better if everyone was fully vegan.

But [again, in the interest of full disclosure of the sake of meaningful discussion] I don't have the same automatic emotional impression of them; it feels like other vegans are providing meaningful, credible, and falsifiable proof of good intent and therefore I automatically am much more trusting & willing to sacrifice for their good; I don't have similar ingroupishness toward amelitarians (or pescetarians, etc.). 

Whether this matters at all depends on what you consider the importance of community in pursuing major & sometimes lonely life changes.

--

I'd strongly agree with the pepperoni/liver argument. Anyone who says the only reason they aren't vegan is health but then buys e.g. a pepperoni pizza seems like they are more likely to be searching for free virtue points than actually concerned about the suffering of animals.^[4]  I'm not expecting humanity writ large to be morally perfect & entirely consistent, so this isn't a judgment on whether those people are "good people."

It seems psychologically much more difficult to be "almost vegan" than "fully vegan" or "not vegan." In my experience it is much easier when eating any animal products to put animal suffering out of the mind than to live with constant internal conflict. My pet theory is that (in fully omnivorous cultures) it is emotionally harder to be a committed vegetarian than a committed vegan, etc.

For leather in particular, consider that the tanning of leather is also a health concern. My shoes are neither leather nor virgin plastic; this is veering off into minutiae, but there are plenty of attractive non-plastic vegan shoes (ex, or more common).

1. ^{^}

   It seems implied that you're equating "full abstention isn't possible" with "full abstention isn't convenient" which is emphatically not what I'm saying. When I say vegans don't use animal-derived ingredients except where it's super impractical, I have in mind e.g. someone getting a vaccine developed using eggs because they can't find an alternative plant-based vaccine. I would NOT include someone who e.g. eats red meat because they are worried about iron deficiency (when they could just take an iron supplement).

   If this is what you meant to imply, then we have a genuine disagreement here.

2. ^{^}

   Provided they are minimizing animal suffering as much as is possible given their circumstances

3. ^{^}

   Relative to global standards, not country average

4. ^{^}

   Though, like I mention in my first post, this is really hard to judge. For example, some people with extreme sensory processing disorder might currently need to eat non-vegan junk food in order to avoid losing too much weight, even if the junk food itself isn't health food. Though I think it's obvious that my bar for this is much higher than yours.

I'll be completely honest and say I came into this post expecting to be annoyed, mostly for reasons you address (especially the "you're singling out veganism" and "sick of concern trolls" issues). However, after reading I agree with pretty much all of your cruxes. 

Particularly, I would agree that most [current] vegans [living in omnivorous cultures] are sacrificing one of health/taste/cost/convenience.

I have been vegan for 2.5 years and have had no negative health effects (at least that I'm aware of, or that I didn't have while omnivorous), but I would also consider myself decently well-educated in vegan nutrition.

I think there are some health issues that may make it too difficult for some people to eat plant based* (ex. genetic difficulties with converting provitamin beta-carotene into proper vitamin A, or simultaneous soy & gluten & nut allergies). I don't think a perfect 100% of humans today could eat entirely plant based* with the agricultural and nutritional knowledge we currently have.

However, I strongly believe:

• The number of people who could be healthy vegans [EDIT: on a plant-based diet] is far, far higher than the number that are currently vegan [EDIT: plant-based]. It's not 100%, but if forced to make a numerical estimate I'd say >=80% (if cost was not an issue), or >=50% of the U.S. at their current income.
• People who are unable to be fully plant-based should ideally still reduce their contributions to animal suffering, insofar as is possible & practical for them. A lot of people seem to commit to failing with abandon if they can't be perfectly plant-based. [This is difficult to judge from the outside though, and I don't feel comfortable passing this judgement on anyone I don't know extremely well, and very few of those I do.]
• If cultured meat production and/or nutritionally comparable meat replacement continues to advance, most objections will be pretty much irrelevant. I would be very suspicious of people who say they can't eat plant-based for health reasons, but then don't switch to cultured meat (/ nutritionally comparable meat replacements) if it becomes easily available.
• There are no negative health effects to avoiding buying leather, for example. You can debate leather ethics on its own merits, but people who say "I think we should stop farming animals but I can't be vegan for health reasons" who also buy leather seem like they are just searching for free virtue points.

All of the vegan places I've hung out in (that talk about practical veganism, not just the broad philosophical argument) have pointed toward the important bits of vegan nutrition. Ex. B12 being a running joke on VCJ. I don't think general philosophical arguments should be required to contain implementation details, but I would consider any practical veganism guides that didn't include at least info on B12 supplementation & preventing iron deficiency irresponsible.

Not sure we actually disagree much, but feel free to let me know. Honestly my biggest disagreement would just be that I don't run into "there are no downsides!!!" messaging much and therefore this seems like a non-issue. Though I don't spend much time reading about EA-specific vegans, so maybe it's more of a local issue?

[*] - retaining a distinction between a plant-based diet (zero animal-origin products in food) and vegan (philosophical framework that extends beyond the diet but also allows more leniency when full abstention isn't possible)