A very interesting paper! It seems it's less important how much protein and carbs you have, and more important when you have it.
All the subjects had at least 6 months' training behind them. They weren't beginners, but intermediate level.
The PRE-POST group (having drinks before and after workouts) began younger (avg 21yr vs 24yr), heavier (avg 82kg vs 79kg, lean mass 69 vs 65kg) and stronger (bench/dl/squat 127/153/148 vs 121/142/148) than the MOR-EVE (having drinks breakfast and dinner) group.
Both groups decreased their food consumption during the trial, from 43.7 to 42.8kcal/kg/day in the PRE-POST group, and 44.4 to 42.4kcal/kg/day in the MOR-EVE group. The PRE-POST group had more carbs (4.79 vs 4.50g/kg/day) than the MOR-EVE group, and less protein (1.92 vs 2.11g/kg/day).
This corresponds to an 80kg person having 383g carbs and 154g protein, vs 360g and 167g protein.
With all that, the PRE-POST group put on about 2.6kg and the MOR-EVE group some 1.5kg lean body mass. The PRE-POST group had a slight (less than 0.5kg) fat loss, and the MOR-EVE group a small (less than 0.5kg) fat gain.
They all put extra weight on their 1RMs for bench, deadlift and squat, with the PRE-POST group achieving about 25% more increase (from an eyeball of the graph).
In sum, the group consuming more carbs and less protein got greater muscle growth. So it seems that for intermediate lifters, it's less important how much protein and carbs you have, and more important when you have it.
Of course, it might also be that even three years makes a big difference in ability to grow, or that when you have more lean mass it becomes easier to add yet more; though I don't imagine the extra 100 or so calories the PRE-POST group had could have made much difference, that's smaller than the likely error from the guys recording their meals.
Interesting stuff, thanks! Now I wonder if studies have been done on consuming the drinks during the workout - we used to do that when I trained in the Army, had a litre of milk, banana and protein powder instead of water.