Scientists do not write books when they have actual, meaningful findings.
You've made this claim all over this comment section, so it's pretty frustrating to find it comes from a pretty awful source.
I promise you, it is trivial to overeat protein. Americans love their 16oz steaks, and yet one pound of steak in a single meal is almost certainly "Too much" for a non-athelete diet.
Meanwhile, simply look to every eating competition which uses a meat. There does not seem to be any natural limitation to overconsuming meat.