It's far easier to get the nutrients you need by being an omnivore (which is what our GI tract is actually designed to handle).
Homo sapiens are not herbivores. Our GI tracts are incapable of processing cellulose, which is why we have a very small caecum and a non-functioning appendix. Moreover, humans do not re-ingest our feces like most other herbivores/vegetative matter ingestors so our GI tract can have another go at it!!! Granted, vegetarians will eat legumes to obtain some form of protein, but if you have a legume allergy, you're FUBAR. BTW, soy is not something you want to put into your body unless you want to be estrogenized.
I think it's much better to try to eat a healthy omnivorous diet than pretend you're something you're not. Tons of people on this forum eat extremely healthy diets that include meat. You can, too.
Just my $0.02.