Protein is broken down into amino acids for cell repair and to produce ATP for energy.
Unlike carbs and fats, it has no storage form, and the excess (unfortunately), is converted back to glucose and fats. We don't pass it out into the urine, nor the feces.
In short, protein utlization is different for say, a sedentary person, to Jay Cutler. If our sedentary friend here consumes 2g of protein per lb. of body weight each day, he'd be wasting more than half of it, since his range would be more in the 0.6-0.8 g area (since he's not in an overly-anabolic state as Jay is). I couldn't even begin to fathom what the Olympian's protein needs are. I'm sure they're through the roof.
Adjust your protein intake according to your weight, and level of activity. Protein is an expensive source of calories, so plan your meals wisely.