Any way that hyper is treated (surgery, I-131 or meds), weight loss of 10-15 pounds may occur but w/ careful attention to diet/exercise, this can be limited.
Not everyone will gain weight after RAI.
I did gain about 10lbs HOWEVER, I did NOT eat healthy...
Once I got on the correct dosage of thyroid medication I started to eat correctly & healthy. Currently considered underweight..
I eat a lot of protein. I am lactose intolerant & can't eat bread, but other than that I am okay..
Still dealing with the correct dosage after 18yrs..