I'm proudly an omnivore, on basis of taste, and I have no morals. (I hate it, whenever I'm in Chicago, there's some radical vegetarian/vegan who comes and rips the hamburger from my hand. I'm going to hit him next time I'm there.)
In the interests of energy, it's more efficient for a human to only eat plants (Only something like 11% of energy eaten by cows, etc. is available to the next level on the food chain, humans) outspoken vegans often point this out, but fail to mention the fact that if everyone were vegetarian, then humans become competition with herbivores for food, and animals wouldn't win. Then food becomes scarce for the animals that eat the herbivores.
It's all about the eco-systems, man.

B"eat meat and save the animals"o