It's not so much about what's allowable as much as what is optimal. Optimal PWO meal would be really lean protein like chicken breast/fish/WPI or egg whites and a good hunk of carbs that don't have lots of fiber in them and no added fat. Ultimately, I don't think it matters too much with respect to the fat periworkout until you start getting calorie restricted or are having multiple workouts per day. I also think periworkout would be the time to have lower protein intakes vs. larger due to how sensitive the body is to amino acids at this point.