I lost 50 pounds in a little over a year. This was from a very high protein, moderate carb, lower fat diet, and LOTS of exercise that featured pretty heavy strength training and lots of cycling/spinning. I was under medical advice regarding all of the above as my successful attempt to reverse the onset of type 2 diabetes.

Since then I've pulled back on the protein percentage (though it is still high), and also moderated the exercise a bit to prevent a repeat of the overuse injuries of last year. I haven't changed the type of exercise, just pulled back a bit on the strength training (only twice a week for the riding season), and no spinning unless it rains. My weight has stabilized and just bounces around in a 4 pound range, though I would love to lose another 10 pounds. I do suspect, however, that if I DO lose those 10 pounds, that I would decide that I needed to go down further...