Losing weight won't hurt your descending.... remember Galileo and the Leaning Tower of Pisa? It's all about aerodynamics, and a few pounds aren't enough to really change the profile you present to the wind.

No matter how much weight you lose, all else being equal, your shorter friends will still descend quicker than you. Just because they're shorter.

And they're useless to draft behind, too. <cue Randy Newman's "Short People">

At 5'3", I can say it.