I think it's more common than you think. After my bypass I could drink and eat anything. Which upon reflection, 20 years later, was to my detriment. I lost 175 pounds in less than a year and 20 years later have gained a total of 60 back. If I could talk to myself then I would say get into a program, Weight Watchers worked for me in the past and get on an exercise regime. I'm very dedicated to my exercising, 3- 5 times per week depending on my schedule, try to stay active and eat well I would say 70% of the time, however age is a definite factor in weight loss. I am 72 and in my 30, 40 and even 50's I could lose weight much easier. You seem to be aware of potential weight gain and that is the first place to start. And remember don't freak out if it's a small gain as your body most likely is stabilizing after surgery. Best of luck to you.