Well, you can still eat vegetables. Preferring poultry and fish over red meat might give some health benefit. Old Ben might argue that humans have evolved in such a way that we can come up with inventive rationales to justify the things that we want to do. I am not saying this is the case. I'm just contemplating the ifs. I have heard that eating meat has far greater environmental effects than following a vegetarian diet. How does entropy come into it?From a personal health standpoint, it's no better or worse than omnivorism.
From a moral standpoint, one could argue against carnivorophagism by saying that carnivores have evolved in such a way that presently, they do not have a choice but to eat meat, whereas we have the choice to or not to, and that gives us an option they cannot consider.
Environmentally, carnivorophagism would be almost certainly worse than omnivorism, because of the second law of thermodynamics.