Crossfit recomends the Zone Diet for athletes to help getting/staying in peak physical state.
The only times i have heard of carb loading are in cases where an athlete is going to take part in an event where a lot of energy is required, in which case they load up on high carb foods (pasta) the night before and/or a few hours before the event.
But you might be leading more towards the 'carb loading/Carb cyclying' phase some body builders go through a few weeks leading up to a contest, this is when they will carb deplete (eat little to no carbs) for a couple of days and then eat lots of carbs for a day, then back to carb depleting. I knew a body builder who carb depleted for a week! She was basically living of tuna/salad and protien shake, then prior to her contest she would eat lots of carbs so her muscles would look more defined/tender. IMO most of the time this has little to no effect, but carb depleting like that for a week will result in muscle loss as well as some fat loss, but because of the rapid change of no carbs, most of the weight lots would be in muscle mass.
I haven't heard much about fat loading, but ultimatly if your wanting a nutrition plan for endurance work i would have a look at the Zone diet crossfit recomends for all athletes.