I'm 200lb, but aside from a layer of "ab protection" as Rob puts it, resulting from sitting on my arse all day, I'm in decent shape. I go to the gym 3 times a week, and eat really well. Never been on a diet.
I had stacked on the weight when Imie was born and I consequently stopped going to the gym. Since I started going back to the gym, it fell off.
Incidentally, I recommend yoga for weight loss. You can buy a (beginner's) tape and do it at home - no gym fees.