Hunger
I had RNY surgery in 2007. My hunger has never returned. I maintain my weight fairly easily, because I am never hungry and when I do eat, I can only eat a small amount.
But I never went back to eating many carbs and never forced myself to eat more than I need, Now I can eat anything I want, but am satisfied with a small serving.
The secret of losing and then maintaining the loss is to always be aware of what you are eating. Myfitnesspal is the best way for me to do that.