I have to disagree. Most doctors will agree that losing up to two pounds per week for a healthy adult is acceptable and normal during the course of intensive exercise.

Much like matwood, I was ~205 at 6' with an athletic build. I wasn't overly fat, but hefty (ok, kinda fat). Running and working out six mornings/week and basketball in the evenings allowed me to drop 2 lbs/week, to a much leaner 165. Coincidentally, I had a doctor visit or two during that time and the doctors never expressed any concern over it.

Fortunately, and I believe this generally for healthy adults, you will reach a plateau. I did so at 165 and never fell below that, even when I increased my running, lifting and other recreational activity.