For example, years ago I did South Beach
and lost a good amount of weight
(probably 20 pounds). It seemed that the very minute I ate one piece of bread, I gained 5 pounds. I'm exaggerating just a bit (not much), but you are limiting yourself to a far, far greater degree than even Atkins or South Beach condones.
You will regain if you severely restrict yourself and simply resume a healthy diet afterwards. If you can then keep eating in a healthy manner and relose the weight, great.