When I was doing bodybuilding, I had 5 meals a day. If you try to smash all your protein together, it's going to be too much all at once to handle. If you're just trying to lose and not sculpt, 1 meal a day can work, but you have to be careful that you get sufficient protein for the reasons Buttworldsman listed.
As always, if something ends up working for you, do that.
@DoubleD the problem with "if it works for you" with regard to the daily protein in 1 meal issue is that it's objectively inefficient. Protein is still protein, so it won't be completely ineffective, but is it as effective as spreading the consumption out and then recovering properly (where the muscle building actually happens)? Doubtful.
@DoubleD That's fine, but results are objective.