Weight regin
SO you eat to the DS strengths. Protein first, lower carb intake. The optifast isn't a bad way to reset yourself and add food back in eliminating some of the things that might be causing your regain.
I sometimes do a week of protein shakes if I've gained into my 10 lb weight gain range that I have before I worry about anything.
Good luck. It can be done. I saw someone wrote about bounceback but that is probably not your issue since you are so far out. It tends to happen nearer when you stop losing your initial weight if it happens.
Pete