This is one of the more common questions physicians hear “is my weight gain caused by a low or sluggish metabolism, could it be my thyroid?”
Probably not, as most overweight individuals do not have a malfunctioning low thyroid gland. Perhaps less than 5% of overweight individuals have a clinically documented case of hypothyroidism, which is usually the result of Hashimoto’s Thyroiditis. Weight gain is most likely a result of a prolonged intake of excess calories and not the result of a low functioning thyroid. However, every overweight individual should have this question answered once and for all, and to see if your thyroid function is low this can be easily determined by two simple laboratory blood tests, the thyroid stimulating hormone test (TSH) and a thyroid blood level (T-4). If the thyroid level is found to be low, but not borderline low, then a thyroid replacement medication could be prescribed. But thyroid replacement will not result in any clinically significant weight loss. Most of the weight gain from hypothyroidism is from fluid retention, not a result of fat gain. Thyroid supplementation when the thyroid is found to be “borderline low” is not medically recommended, as it will not help with weight loss, and it will interfere with a normally functioning thyroid. In most cases the thyroid gland is an innocent bystander to weight gain. Hope this helps with your understanding of weight management. Peter Vash, M.D.