Don't listen to him, for some reason, there is a lot of anger cast in the direction of vegetarians, it's like you are slapping meat eaters in the face, I don't quite get it. I think people associate vegetarianism/veganism with PETA, and various animal rights extremists. A word of advice, don't shove your newfound beliefs down everyone's throats, otherwise you'll get into more scuffles with meat eaters (trust me, there are more coming to this thread who will argue with you)
But you do need to take into account that YES, it is very unnatural, and you will need to start taking vitamins or finding some other means of getting protein. Warning, all vegetarian specialty food seems to be ungodly expensive, which is one of the reasons I returned to meat.
Do some research outside Talkbass and find out what you want to find out (Google is pretty amazing), and start reading labels: If you are really going to stick by your guns, you'll have to make sure that your vegetable dishes don't contain gelatin or beef stock... or whatever.
As long as you supplement the nutrients you'll be missing from meat, it's a perfectly healthy way to live. RESEARCH ABOUT SOY though, it's advertised as this miracle health food, but it's been known to cause some health problems.