• You should ask a dietician, not us.

I know plenty of LW people are interested in nutrition; it's within the realms of possibility that one of them might know enough about what I'm asking to be able to give me a quick summary of what I'm after. As for asking a dietician, I've never met one and wouldn't know how to go about getting hold of one to ask. (I'm also not totally sure I'd trust J. Random Dietician to have a good understanding of things like what counts as good evidence for or against a proposition. Nutrition is a field in which it's notoriously difficult to prove anything.)

• There are many other vegetarians; this seems like it should be a solved problem.

Well, erm, yes, that's why I'm asking about it. (I don't go around making posts asking for proofs that P=NP, for example.)