There is no reason for anyone to take in 400g of protein, unless you have 300lbs of LBM. 1-1.2g/lb of LBM is all that's needed with a Max of 1.5g/lb.
Anything more than that is wasted and just extra kidney stress. I will try to dig up the study, but it has been found that the most amount of protein that the human body can synthesize is 1.6g/lb, but that was with ideal conditions, food intake, and digestive aids