The only morally sound answer to that question is "anything or nothing" because any other choice implies that you have to justify why one organism is more worthy of life than another. Am I wrong or just not fun at parties? :D
1) Eat anything your body can consume safely
2) Only eat things without brains
3) Only eat things you hunt/harvest/prepare yourself
4) Only eat animals that are already dead
5) Only eat plants and animals that are invasive or over populated
And the list goes on. Some are easier than others, but I don’t see the moral dilemma in maintaining a certain diet outside of “anything or nothing”.
I hope my dinner knows how delicious it is before I eat it. I would tell it if I could. Although that could get pretty awkward if it's something I don't like much:
"Listen, can we just agree that neither of us is really going to like what is about to happen?"
That's pretty much the only way I eat animals. It may be anecdotal, but supermarkets near me sell all of their meat pre-killed in neat little packages. I've never had to grind the beef off of a live cow to get my burger meat. Lobsters are an exception to that rule, but still generally seem dead by the time people eat them.