It varies greatly, but most men that follow their plans tend to lose very quickly. I would guess people lose 10-20lbs a month on average in the early months. I, personally, lost 185 lbs in 10 months. I would say I lost on the "faster than average" category, but certainly not unheard of by any means.
It always blows me away to see the posts on WLS sites saying "I've only lost 25 pounds in the first 5 weeks and nothing for 3 days, why am I losing so slowly?!?!?!"
Out of curiosity, how tall are you and how did you come up with your goal weight?
I am 6'3" and started out at 450. I got to 199, so your goal is totally possible. I lost 30 pounds the first month, but everyone is different. I would say to stick to your doctor's plan, don't cheat and move, move, move. Just walk as much as you can. All of it adds up. It "easier" to lose weigh early on so take advantage. Once you get a year or so out, each pound takes more and more effort to lose.
Good luck, you got this!
Men and younger women tend to lose the weight the fastest. For young women, take the same woman (same weight) at 30 vs 50. At 30 she can move better and her heart is probably stronger. Also men (in general) have a larger muscle structure. The weight come off of us quicker. A sure way to loose more weight while you are dropping, is to buy new clothes! You think you are done losing, so you spend big bucks on new clothes...To look nice. WHAM!! You end up dropping another 10 pounds. So you may want to ask friends, family, coworkers for used clothing till you get near goal. My favorite pair of jeans came from my nephew the first year out. He didn't need them and they fit fine for me. Try thrift shops and Goodwill till you get near goal. One week I lost 10 pounds!! I was eating right and exercising hard (doctor's approval). Also know the signs of dehydration. Dehydration is the # 1 reason WLS people reenter the hospital. Just have the signs printed out somewhere so you can look at them and know what is going on...Brian