Your weight gain from taking Iodine is called Bloat, and is a symptom of detox. When you take iodine, this displaces toxins in the cells of your body. Too many toxins entered your bloodstream at one time, more than your liver & kidneys could dispose of. It means you started with too much Iodine too soon, or you weren't taking >>all<< of the required co-supplements that help to rid your body of toxins.