According to the references I found, gastric bypass can be reversed for medical reasons alone and even in those cases the risks are very high. See e.g.
http://www.slate.com/articles/news_and_politics/explainer/2010/02/can_bariatric_surgery_be_reversed.html
Thus, I believe that the doctors don't leave the unused parts there for the possibility of reversing it. The reasons must be something else. Those of you who are still planning, please ask your docs, I would really love to know.
Our weight fluctuates daily based on a number of factors (water intake, where you are in your menstrual cycle, how much Water your body is retaining on any given day, bowel movements etc). I would pretty confidently say that the scale isn't giving you false readings and is instead just demonstrating that our weight is more than how much body fat we have. As many suggest on this site, either weigh less often so you can get a better sense of whether things are generally moving downwards, or learn more about the factors that cause weight gain or loss and become more comfortable with daily fluctuation. I weigh daily and don't get discouraged anymore by day to day fluctuation. Hope that helps, and good luck!
