What those guys said. During the last week you are on a very catabolic diet to get as much glycogen out of your system as possible. After sodium depleting you have basically made your skin as thin and transparent as paper as you possibly could have so that you have relatively no fat or water retention. Its a tricky thing to do the carb load before the event because no one's body is the same, that is why alot of people have to compete more than once to make it to the inner circle of winners.
The beautiful thing about carb loading after completion of glycogen is that if timed right, you can come into the contest looking ripped and very hard as well as full of muscle because the muscles will absorb all of the glycogen it can get prior to any other tissue in the body. The muscle has to function most because the muscle as been programmed for survival and function first. Ergo, the muscle receives the carbs first and will fill out quite nicely.