I'm not sure that the issues I had were thyroid or not, I never tested more than borderline. But I had a lot of the classic symptoms - hair loss, extreme fatigue, cold, muscle soreness after going VLC. When I switched to primal by removing bread and pasta, I essentially removed any major sources of carbs. I was consistently under 50g/day, more like 30g/day. I discovered after about 2 weeks that iwas not the right way for me as I got severely depressed.
I added more carbs, mostly in the way of potatoes 4-5 days/week and feel much better. I simply need more carbs to function. I know lift 3x/wk, play soccer once, have energy to play with my kids, and am still losing 2-3lbs/month. So it's just about finding what works best for your body.