I guess I began to be a weight that my body was supposed to be. Once I went on Tapazole, I started to gain.

Overall, the researchers found that there was a 32% increase in obesity in previously hyper-thyroid patients following RAI therapy, with the main weight gain coming in the first 2 years. Two years after treatment, only 8.7% of patients were underweight and 51.3% were obese. Before the therapy, 27.5% were considered underweight by body mass index calculations, and 19.3% were obese, with a body mass index above 30. In fact, one research study found that more than 85% of patients receiving RAI became hypothyroid, and despite being treated with levothyroxine, their median weight gain was 11 pounds after 6 months, 20 pounds after 12 months, and 25 pounds after 2 years. Doctors who tell you that they can somehow calculate just the right amount of RAI are living in fantasyland, because most patients post-RAI become hypothyroid, and many complain of weight gain. If you are treated with radioactive iodine (RAI), you will most likely become hypothyroid, and you will in all likelihood gain weight. I gained maybe 5 pounds the whole time (months and months) I was hyper. I ate Dairy Queen on a regular basis and was outeating my 6'2" boyfriend. When my thyroid was hyper, I was literally eating four to seven meals a day.

I always felt light-headed and would get dizzy spells. My mom was convinced I had an eating disorder. In high school I wore a size 4 and I'm 5'9"! Miya had this experience: I used to be chronically underweight.