Thinner Peace

I am 200 lbs and my goal weight is 135 (high range for my height). My surgeon says that I will only get down to 150 (which is still considered overweight). I have already lost 30 pounds getting ready for surgery. Is it wrong for me to think that I can lose more than 50 pounds after being sleeved?

I gained my weight by destroying my metabolism with extremely low calories. How do you keep from regaining weight when you are on regular foods (i.e. a year out)? Doesnt surgery ruin your metabolism?