Jan - Feb 2015

Thyroid and Obesity

By Raymond G. Lau, MD and Antonia Pinckney, RD CDE RN


The thyroid is a butterfly shaped gland located at the front of your neck. Part of the thyroid’s job is to regulate how we burn calories. It secretes hormones that are routinely measured in blood work.


Among other things, thyroid hormone levels can affect our body weight. Those with an underactive thyroid, also known as hypothyroidism, may burn calories at a slower rate leading to weight gain. Those who struggle with obesity, often wonder if a thyroid problem may be a cause of their weight gain. For these individuals, supplemental thyroid medication may be needed.


Some researchers think obesity effects thyroid hormone tests. In fact, some studies show that the fat accumulation in obesity causes thyroid blood tests to suggest a mildly underactive thyroid or hypothyroidism (1). Researchers are working to better understand these effects.


Individuals with hypothyroidism that experience changes in weight by any method, surgical or non-surgical may need an alteration in the amount of thyroid hormone medication required. Often times, if your weight decreases, the amount of thyroid medication that you need will also decrease. However, for those who have had malabsorptive surgery such as gastric bypass, the amount of thyroid medication may not be completely absorbed, and you may actually need a higher dose.


If you have undergone weight loss surgery, and you have an underlying thyroid condition, be sure to ask your doctor how frequently you should have your thyroid hormone levels checked. Making sure your thyroid hormone levels are regulated is important for your overall health. If there is a problem regulating these levels, an endocrinologist is recommended for a consltation.




(1) Douyon, L and DE Schteingart. Effect of Obesity and Starvation on thyroid hormone, growth hormone, and cortisol secretion. Endocrin Metab Clin N Am 31(2002) 173-189


(2) Biondi, B. Thyroid and Obesity: An Intriguing Relationship. JCEM Aug 2010, 95(8):3614-3617.