I had the same problem in 2008 after dropping 60 pounds in 9 months. I had a very successful gallbladder removal, but I am not the person you should listen to. I was doing moderate walking after a week, back at work after 2 weeks, gradually easing into riding at 2 weeks, and by 6 weeks, I did a duathlon. It took me that full 6 weeks to get back to where I was in training before the surgery, but I listened to my body and went at the pace that it could go.