I weight 192 pounds. I have spoke to people that weighed more when they had they surgery and did fine.
You may want to check and get a second opinion, however, depending upon what you weight is it may complicate both the surgery and any possible positive results you might get from the procedure. The weight will continue to push your stomach upward and your tissues may not be able to maintain the closure between the lungs and the abdominal cavity. That 'closure' is very necessary to maintain the balance of pressure that allows you to be able to breathe well.