> The issue is not the absolute number but that you are using more to produce less

I was under the impression that's how it is with all animals, they always need to eat more than what you get from them in terms of calories which usually will also equate to more weight (the comparison used here) in than out.

Otherwise we'd have found some feeding process that's over 100% efficient which doesn't seem possible.

In other words, they poop while they grow, unlike plants where the efficiency looks better.