The researchers compared the patients' weight gain with that of a matched comparison population of nearly 11,000 people who did not have an overactive thyroid.¹. It will take awhile, but if you decide on a diet pill i would consult your dr. since you had both your thyroid and parathyroids removed. after surgery weight loss loss Weight Loss After Thyroidectomy Surgery after surgery of his vision. So I ate a couple of slices of roast beef and a small bowl of melon a couple of times a day and that was it. 5.2k views Answered >2 years ago. Weight loss. If you are on meds then my advice is still the same. Losing weight after a thyroidectomy (Weight Watchers ... - City-Data Weight gain after thyroidectomy : I am 63 yrs old... - Thyroid UK Weight Management After Thyroidectomy. Weight loss has been more difficult for me since surgery, however, once my new doctors (I moved a couple hundred miles, so I needed new doctors.) Your thyroid hormone levels should be measured to ensure that they are in a normal range. If the levels are too low, you may not be able to lose weight. The dose of your medicine will then need to be increased by your physician. Reduce the number of calories that you consume. If the thyroid gland is removed through a procedure called a thyroidectomy, your metabolism is disrupted from the lack of thyroid hormones.