My body gains weight if I don't eat 1,200 calories or more and it attempts to hold onto any fat I have. Just try to get more protein and see if that works.
I don't eat 1200 everyday. The other day I had 1800 and worked out. And I've been eating a ton of protein. Last night I had a protein shake and seitan for dinner. I know I'm not actually gaining weight. It's my water weight just fluctuating.