I started working out May 06...I started to workout with the Total Gym 1700. I weighed about 185pnds. At the end of the summer around September I weighed in at 160pnds. I also Rode my bike like crazy, maybe 14-20 miles four times a week. It took me about four mnths of heavy exercise to see any results. My problem was I didn't workout in the four years I was married, plus I'm 37 years old.
I totally had to change my diet and mentally get into it. So basically I would tell you to take your time factor in age, diet and have a realistic goal. I think gaining weight to fast could be just as bad as losing.
Right now since I lost...I want to put it all back on with lean muscle, I'm going to buy a BowFlex in the spring. Good luck with your goals.