The last 50 pounds is hard for me to lose! 10 months ago I was tipping the scales at 275. I hit a low of 220 before the holidays, and then ballooned up to 242 in a month! Since January, I have gotten my weight down to 233, but it's like my weight hits 225 and my body becomes a weight magnet!
As I've gotten lighter, exercise is becoming easier, and so I'm doing it more frequently, but it is absolutely about diet for me. I would say that exercise is only 10-15% of the weight loss equation (in my experience).