RAMADAN MUBARAK!!!

Salam, everyone! Another Ramadan is here, Alhamdulillah. Best wishes to you all for a happy, healthy Ramadan. Now, I have a question... Surgery was 7/24 (RNY), and I really, really want to fast. I feel that it's the least I can do to thank God for all He has given me lately, especially preserving my life and health as I went through and recovered from surgery, as well as taking good care of me and my family last year in the wake of Hurricane Katrina (we lost almost all our possessions, but Alhamdulillah, none of our close friends and family). My mother, however, is worried that I might develop some kind of metabolic problems if I fast. She's especially concerned because just a few weeks ago, our good friend (who had a BMI of at least 60 and many, many health problems) developed kidney failure and a pulmonary embolism and died a few days after surgery. Any thoughts? How soon after surgery did you fast? Any help you can offer would be wonderful, Jaz *** Allah.