I have thyroid issue... So about couple months ago, i went to the doctor due to atypical menstrual cycle, done some blood works and found out that I have hypothyroidism. You know the excuse that every obeast uses? I am experiencing all of the symptoms and including weight gain from 115 pounds to 121 pounds.  Then I decided that I would like to keep my weight under 120 and it took me less than two weeks to go back to 117.  So we know no hormones would cause you to gain THAT much weight and you can still control your weight through diet/exercise. Fats will never believe this though :)