I am over 8 years post-op (RNY) and 30 years post-op gall bladder removal. I started doing a one-meal-a-day, 23-hour fast 3-4 days a week and eating a normal diet on the other days. I do a 3 day, water-only fast once a month.
I have found that I feel wonderful on the days I fast. It feels right. I'm not sure how it would have felt shortly after surgery, but this far out I'm pleased. Not particularly hungry when I'm not eating.