I too am hypothyroid and over 40. This is a DIFFICULT combination...but do NOT DESPAIR.
All of a sudden, traditional weight loss plans just stopped working.
And I exercised kind of a lot!!!!
My doc put me on something like the primal blueprint plan and it IS working!!!!!I have posted about it here in places.
Basically....no dairy, grains or sugar.
I eat lots of veggies, even juice them now and again. I also eat lean meats in moderate portions...am working on buying most of my meats from the best sources.
Consider getting the Primal Blueprint book or something like it.
Hang in there.....it WILL be worth it in the end.