Well, to be perfectly honest, each religion has it's own beliefs.
However, facts remain that humans weren't exactly made to eat meat. I say that, being non-vegetarian myself, though!
Our teeth weren't made to chew meat, nor was our digestive system. Our alimentary canal is very long and food, especially meat, takes a very long time to digest as compared to carnivores, who digest food very quickly. So that basically means, the meat might rot in our system, because it stays there for so long (I'm not trying to paint the wrong picture, just saying!).
But religiously, I'm not supposed to eat meant. Well, I don't eat beef, coz they're really against it, being Hindu.
An do, I don't think it's against God to eat meat, but then again, what are veggies for? So you can argue both sides and could go on forever...but I guess more than anything, it's what you choose and believe...?