Here's a datum for those of you interested in weight gain/loss in Peace Corps: at 70.5 kg (155.4 lbs) I'm now lighter than I've been since I was a freshman in college. Back then, I went from a meager 135 to 165 lbs in about six months of hitting the weights pretty hard.
I attribute the loss to not eating very much and running a lot. A couple weekends ago, for a variety of reasons, I went almost 2 days without a meal. The old "too-lazy-to-cook" bachelor syndrome, I'm afraid.