Hey there!
How long has she been on the Synthoid? When was she diagnosed as hypo? I'll give you my hypo experience (the extremely abbreviated version):
Fall 1999 - managed to gain 15 lbs without changing workout/nutrition program (at the time I was a bit obsessed, shall we say...competed in fitness competitions). For almost two years I fought what seemed to be a losing battle with my metabolism. My body essentially had shut down, thanks to anorexia as a teen, extreme dieting, and excessive exercise.
May of 2001 - diagnosed as hypothyroid and was put on Armour Thyroid, which is a pretty rare course of treatment these days...I had a pretty hip endo, though. He was Armour all the way. Boy was the next three years a struggle. I was on a thyroid rollercoaster, trying to get my levels adjusted. Periods of stress would send me into a hyperthyroid state. I felt horrible more often than not.
Fall of 2004 - was put on 112 mcg of Synthroid and have felt pretty awesome since!
I know that's probably a bit more info than you wanted, but i'm willing to share any insight into the disease that you may need. Hormones are tricky...if the levels of one are off, the others seem to follow suit.
How long has your client been exercising?
Are you ABSOLUTELY SURE she is eating as she's saying?
Hope this helps!
Sarah
“Outside the Box” Training