I was diagnosed hypothyroid 3 years ago and have yet to successfully lose any of the weight I gained before diagnosis. Last year I was extremely diligent for 4 months, tracking every calorie, working out at the gym 5 days a week, swimming 2x a week. I put so much effort into it, and lost only 6 lbs. Frustrating!
I've heard it can be done, that low carb is the best route, and that daily aerobic exercise is a must. I know it's more difficult and takes even more motivation and discipline than before I had thyroid issues... I'm still working on that.