It is not so much about the lack of meat
It is really about the presence of quality foods in you diet.
I could eat only cheese pizza and drink beer, and I would be a vegetarian
Do some searching on this site, and on google and you will find more reading than you will ever have time to take in.
One quick thing to be careful of is you will need to make sure you are supplementing your B-12 vitamin, and also your Omega Oils.