The short and honest answer is... you won't unless you watch what you eat for the rest of your life! What doctors don't tell you is that when you have most or all of your thyroid removed you will never be the same again (& neither will your figure!). No hormone replacement known to man can make your metabolism normal again.. even if you have to take thyroxin for the rest of your life! So limit your food to healthy... lots of fresh low carb vegetables ( eg zucchini/squaah/lettuce/sprouts & no more than 2 pieces of fruit per day. Most impotantly make sure you eat limited carbs ( you are at high risk of developing type 2 diabetes/ high blood pressure/heart condition... the list goes on. You will also need at least 8-9 hours of sleep per night & be prepared with extra blankets in winter because you will feel the cold (& conversely in summer). Exercise moderately.. you can exhaust your adrenal glands more easily as your thyroid isn't there for back up.. just take a balanced approach. Fast once a week to clear your bowel as it will be slower due to the lower food intake. See a naturopath for bowel cleansing formula... you will feel much better when you do it regularly. Buy an entree' sized plate to eat dinner from... most restaurants serve entree size & if not then just take half of the food off the plate before uou start ( or leave it there afterwards. Most servings these days are miles too big... so take pride in the fact that you wont be joining the 'fat' revolution! Most importantly of all... see your doctor regularly so as to monitir your cholesterol and fasting glucose. You are entitled to live a long and healthyblife like anyone else... but its u to you to make sure ithat happens! Regards Debra (I had most of my thyroid removed @20 years ago).