The standard recommendation is 1.0 to 1.5 g/kg of lean body mass / day, but Prof. Bikman recommends up to 2.0 g. Dr. Naiman claims that “too much protein isn’t even a thing.” Other experts recommend considerably less. This is all in the context of low carbohydrate intake, of course. I am leaning towards the logic of those who recommend more, rather than less, but am prepared to revise my thinking as new evidence comes out.
When I started on the forums, the big fear about protein was that too much would be converted by the body into glucose and spike insulin; but we know now that the process of gluconeogenesis is driven by demand, and the body finds other ways to use exess protein if it doesn’t need glucose at the moment. The more serious concerns, as I understand them, are (a) not getting enough protein to sustain muscle mass, and (b) the gradual decline of our ability to assimilate protein as we age.