Since the body isn't moving, the muscles get the time they need to repair themselves and build new tissue by using the high - quality food you've eaten during the day. (fitnessandpower.com)
Of course, this does not mean that you will simply build more muscle once your body gets used to the higher protein intake, rather a more reasonable suggested would be that your body is learning to oxidize any surplus protein (basically use any protein you aren't using for building new tissues as a fuel). (truthaboutprotein.com)