First, talk to your doctor about your health issues, I wouldn't want you to get hurt.
Second, don't do it as fast as I did, it is unhealthy, but effective.
1. Decide you really want to do this. That you are willing to not eat a pizza when everyone else is, or icecream cause you want to, or junk food of any kind. Decide that these things are temporary, that they have nothing for you but fat, regret, and regret, and regret.
2. Get at least 1 empty 64 oz bottle. make a mark at 32 ozs. Drink at least 2 full 64oz bottles a day of water. Do not drink any calories, no full blown sodas, no juice, no gatorade. Stay away from caffine, it inhibits insulin production, and insulin is needed to burn fat, so you want to have good insulin production, don't you! Drink the water at room temp, cold water is a bad shock for your digestive track, infact, if you get a little backed up (you know what I mean) drink some warm water and wait 10 minutes.
3. get a calorie counting booklet in the grocery aisle, leave it on the kitchen counter and start counting everything that goes in your mouth. Be conservative and round up. After all, lying to yourself is not a good relationship. If a tomato is 25 calories, you eat most of it, count all 25 not 21. Bookmark a calorie counter page, there seem to be a few at the bottom of these pages.
3.5 Counting calories only happens when you watch your portions. Stick some kitchen measuring spoons and/or cups out to use. If a half cup of Edy's slow churn icecream is 130 calories, you need to eat only a half cup, not a packed solid one either, remember you will not trick your body! It isn't going to pretend that you didn't eat 300 calories because you had a multiple portion.
4. Eat protein, but don't count carbs. As long as you are eating fruits, and veggies, they are good carbs, cookies are bad carbs. You need to eat some everyday. I always drink lots and lots and lots of water with my proteins.
5. Eat lots of different stuff. Variety is good. Use spicey things when you can, your body will feel more satisfied.
6. Chew your food till it is nearly liquid in your mouth. Saliva sends signals to your brain and stomach that help you think you are full. Plus it helps with indigestion.
7. Take a good multivitamin. My Dr recommends Centrum. He recommended for me, a 44 yr old with a good thyroid, B complex, C, & Omega3 too. All I bought at Walmart. According to some studies I read theirs were as good or better than GNC's.
8. See your DR before any of this.
9. Do some excercise. I have a very bad ankle and can't run, or walk alot. i reduced my calories because I am sedentary. if your active, then you will need more calories.
10. EAT NO FOOD OF ANY KIND AFTER 7:30PM!!! THIS IS A FAIRLY HARD RULE OF MINE NOW. I never have made a good choice late at night, and my body doesn't need it anyway.
I could give specifics but I am not a DR, I don't have a thyroid issue, and I am older. But I promise this one thing, when you are ready for it to come off, you will do it. All you need to do is decide you want this more than junk food, pizza, and candy, or late night snacks.