This is too generic a question. Let me try and give a high level view. There are 2 types of Thyroid (apart from being normal). One is Hyperthyroidism or an overactive thyroid gland and two Hypothyroidism or an underactive thyroid gland.
I assume you are referring to hypothyroidism where you should avoid all Junk
foods and refined flour. Avoid using uncooked cabbage or cauliflower, broccoli etc as this will reduce the absorption of medication. However cooked cabbage, cauliflower etc should be OK.
Excessive iodine is contraindicated in patients with thyroid dysfunction.
Protein and vegetables
Everyone should eat iodized salt to prevent thyroid problems, a slow metabolism, and weight gain.
Avoid gluten and milk products as certain auto-immune thyroid disorders may be caused by such intolerance. Also, do not take lithium if you have mood disorders. Lithium suppress thyroid function.
A thyroid uptake scan wouldn't normally be needed unless it is suspected that thyroid tissue was missed during surgery (sometimes thyroid tissue can be found in other areas of the body), or the reason for the surgery was cancer and the removal of all the tissue is vital.
No, you should eat protein before and after, but drink a lot of water during.
Cutting out foods that naturally block iodine helps with thyroid conditions.
Green vigetable
thyroid gland
This sounds like pica - you should talk to your doctor about odd cravings. No chalk is not flavored.
There are several foods you should eat during pregnancy. You should eat green vegetables and drink juice.
There are no foods that you 'should' eat during your period. You can eat anything that you would normally any other time of your menstrual cycle.