The heme iron in meat is absorbed better than the non-heme iron in iron supplements, but Impossible Burger has heme iron. It's very frustrating that this biotech advance of in vitro heme production is so far only used for this specific brand of meat substitutes but that's the situation. I'm not sure why iron supplements didn't work for you, as that same paper shows that even non-heme iron is absorbed well when blood iron is low, but maybe it depends on the individual? In any case, and I promise the company isn't paying me to say this, I recommend Impossible burgers to vegans. It has to be this specific brand, they have the patent. There was another company with a heme production patent but they recently shut down.

Eat 7 days in a row a large amount of meat. E.g. 1kg of chicken every day.

On most axes except cost (i.e. ethicality, health, antibiotics exposure) replacing chicken here with beef is better.

I don't really understand. Why wouldn't you just test to see if you are deficient in things?

I did that, and I wasn't deficient in anything.

I've also (somewhat involuntarily) done the thing you suggest, and I unsurprisingly didn't notice any difference. If anything, I feel a lot better on a vegan diet.

If you want to do the thing hes suggesting here, I'd recommend eating bivalves, like blue mussels or oysters. They are very unlikely to be sentient, they are usually quite cheap, they contain the nutrients you'd be at risk of becoming deficient in as a vegan, and other beneficient things like DHA.

Or try to buy lab grown meat paste? I am given to understand that they are expensive but available

edit: upon further research it seem you can only get them in Singapore and with a very limitted selection [?one]

they said that they were no longer asexual (they never were),

I'm somewhat skeptical of the claim in parentheses. It certainly sounds like there is a state where they demonstrated enough traits to think they were asexual, and that information tends to be worth tracking, even if only for self-diagnostics.

This generates a lot of data on how much of a positive impact [on cognition] eating meat has.

Is there really no data on this already?

Are we not at the point where any effects can be reduced to nutritional content which can also be intaken in vegan ways? After all, things are fundamentally made of things much smaller than the level of analysis of "meat" or "not meat".

This post is unfortunately not useful to me as the suggestion seems based on the anecdote of someone who was iron deficient, so approximately no evidence in either direction for me, as I already knew of that class of people, and it's not infeasible to intake iron; for me, a useful version of the post would focus on the above two questions.

I want to push back a little in that I was fully vegan for a few years with no negative side effects, other than sometimes being hungry because there was nothing I would eat and annoying my friends with requests to accommodate my dietary preferences. I even put on muscle and cut a lot of fat from my body!

I strongly suspect, based on experience with lots of other vegans, that vegans who struggle with nutritional deficiencies are bad at making good choices about macro nutrients.

Broadly speaking, the challenge in a vegan diet is getting enough lysine. Most every other nutrient you need is found in abundance, but lysine is tricky because humans mostly get that amino acid from meat. Getting enough isn't that hard if you know what to eat, but you have to eat enough of it in enough volume to avoid problems.

What does it take to get enough lysine? Beans, lots of beans! If you're vegan and not eating beans you are probably lysine deficient and need to eat more beans. How many beans? Way more than you think. Beans have lots of fiber and aren't nutrient dense like meat.

I met lots of vegans who didn't eat enough beans. They'd eat mushrooms, but not enough, and lots of other protein sources, but not ones with enough lysine. They'd just eat a random assortment of vegan things without really thinking hard about if they were eating the right things. It's a strategy that works if you eat a standard diet that's been evolved by our culture to be relatively complete, but not eating a constructed diet like modern vegans do.

Now, I have met a few people who seem to have individual variation issues that make it hard for them to eat vegan and stay healthy. In fact, I'm now one of those, because I developed some post-COVID food sensitivities that forced me to go vegetarian and then start eating meat when that wasn't enough. And some people seem to process protein differently in a way that is weird to me but they insist if they don't eat some meat every 4 hours or so they feel like crap.

So I'm not saying there aren't some people who do need to eat meat and just reduce the amount and that's the best they can safely do, but I'm also saying that I think a lot of vegans screw up not because they don't eat meat but because they don't think seriously enough about if they are getting enough lysine every day.

Does it have to be a highly sentient animal or does clam chowder count? :)

Edit: I posted without thinking. I just noticed this sounds sorta inappropriate given your serious personal stories (I should have read them before posting). Sorry, social media is a bad influence on me, and social skills are not my thing. But earnestly asking, do you think clam chowder etc. would work?

You mention seeing iron deficiency on a blood test and I wonder what your test results were/are for ferritin and the other components for measuring iron deficiency. I also wonder if they are higher after you eat meat for a while versus when you are abstaining. That sort of detail would make this anecdote easier to learn from. As is, I can't tell if it's applicable to me.

I'm supplementing creatine based on some tentative studies that may not replicate but also based on my n=1 experience that I feel a bit smarter with it. But hard to tell if it's placebo or not.