ALL protein is absorbed. Just not all at once. You absorb about 7g per hour. Your body will slow down transit time to absorb it all.
You can make 170g of glucose through gluceoneogenesis a day. Hope those numbers are right, someone correct me if wrong.
Leangains or even the Warrior Diet will not cause protein to go to waste. The thing is if you eat in a 4-8 hour window, throughout the fasted period your body will absorb it all so by the next eating window it can absorb more, 16 hours is more than enough time to absorb all protein by the next meal.