In the study (linked below), the all-at-once subjects retained more of the same amount of daily protein than did the over-three-meals subjects.

http://www.ncbi.nlm.nih.gov/pubmed?Db=pubmed&Cmd=ShowDetailView&TermToSearch=10357740

I don't consume all that much protein, since I'm not a bodybuilder but instead a late-30s guy just trying to stay in shape. Yet when I do eat protein conscientiously, I try to do it all at once and center it around my daily exercise (contrary to the advice given below). I eat my tuna, or chicken, or burgers, or whatever, but I top it off with some Amino 2222s (see my post above) to ensure I'm getting enough protein to maintain my muscles and maybe build them.

http://spotmebro.com/layne-norton-phd-on-protein-how-much-and-how-often/

"Perhaps the group consuming the small meals never reached the threshold required to initiate a significant response of protein synthesis at any meal whereas the bolus dose group ate enough protein in at least one meal to initiate one significant increase in protein synthesis above baseline during the day. Now I am not in any way shape or form implying that we are better off just consuming one large protein meal per day. What I am implying is that it is better to consume larger protein doses spaced further apart and maximize protein synthesis, rather than consume smaller doses of protein throughout the day, since research has shown that protein synthesis will become refractory to constantly elevated levels of amino acids. It may be that a period where amino acids return to baseline or near baseline is required in order to initiate another bout of protein synthesis. I therefore suggest that one consume 4-6 larger protein doses per day instead of 6-8 meals and wait 4-5 hours between meals rather than 2-3 hours."