I'm currently unconvinced either way on this matter. However, enough arguments have been raised that I think this is worth the time of every reader to think a good deal about.
http://nothingismere.com/2014/11/12/inhuman-altruism-inferential-gap-or-motivational-gap/
I'm going to comment on the general issue, not on the specific link.
I'm a carnivore, so what I'm going to write is my best approximation at purging my reasoning of cached thoughts and motivated cognition.
I'm not convinced that present-day vegetarianism is not just group signalling.
Of course you wouldn't want aware beings to suffer pointlessly. But from there to vegetarianism there's a long road:
All these points are taken from granted in the article, but they are far from being so.