I've been hypothyroid for many years, and it is almost unheard of for anyone in developed countries to develop thyroid problems from diet. There's a lot of misinformation on the internet about 'needing' carbs for your thyroid It's nonsense.

Seven of 10 cases of hypothyroid are due to Hashimoto's, an autoimmune disease (that's what I have). I have an excellent endo who knows I eat very low carb (and loves the fact that I do), and he assured me that eating low carb is very healthy--for me and my thyroid.

In fact, on some thyroid boards, women have mentioned that they've only been able to lose weight with low carb eating.