Good luck. I've been thin all my life, but last August I was down to a sickly 140#. At 6'1", that was pretty scary. As soon as I quit smoking, the weight started going on. I wasn't too concerned about it and by November when I finally started working out, I was up to 170'ish. Five a week workouts since then just to tone up a bit and now I'm tipping at just a hair over 180 and feel pretty good about it. My frame can probably take another 20# and be good to go. I'm just now beginning to work on my abs since my previous problems were lower back (pinched nerve), upper back and cardio (from smoking 30+ years). The only caution I'd give is to do a complete body workout so you develop as you gain. I see a lot of guys at the local fitness center (Las Vegas Athletic Club) with really nice upper development and chicken legs. Again, good luck and have fun.