Is My Thyroid Making Me Gain Weight?
Main points:
The thyroid produces hormones, triiodothyronine (T3) and thyroxine (T4), that help regulate energy expenditure, or the amount of calories your body burns.
Hypothyroidism is when the thyroid doesn’t produce enough T3 and T4, which may result in up to a 20% reduction in energy expenditure, or about a 300 calorie decrease per day in an average female. This may be partially offset by a decrease in appetite and food intake.
Weight gain from hypothyroidism is pretty modest, averaging between 5-10lbs. A portion of this can be attributed to salt and water retention.
Potential causes include: Hashimoto’s disease, thyroidectomy, radiation therapy, long term use of oral contraceptives, pregnancy, menopause, obesity, goitrogens, and mineral deficiencies.
To see if you have hypothyroidism, get a blood test measuring your thyroid stimulating hormone (TSH). The normal range is 0.4 – 4.0 milliunits per liter (mlU/L). TSH levels higher than 4.0 mlU/L may indicate hypothyroidism.
A common medication to treat hypothyroidism is levothyroxine, a replacement for thyroid hormone that can help restore normal levels.
There is more to weight loss and metabolism than just the thyroid. Healthy lifestyle habits are still your greatest tools for losing excess body weight.
Weight loss frustration
Have you gotten to the point of your weight loss journey where it just seems impossible to make any more progress? Even though you’re paying attention to all the right things, the scale just doesn’t seem to budge.
In instances like these, it’s only natural to look up if you’ve got a condition. I totally get it! Weight loss is hard, and when it doesn’t work the way you expect it to, you’re going to look for answers that you don’t already have.
And one of your landing spots on Google is probably…a thyroid issue. I mean, you’re here right? So before we start, let me tell you this first: weight loss encompasses so much more than just your thyroid.
Resist the tendency to pin all your struggles to this one thing. With that being said, your thyroid does play a role, and it can make your journey more difficult if it’s not working the way it should.
What is the thyroid, and what does it do?
The thyroid is a small gland located in the middle of your lower neck. It produces two hormones that are involved in regulating your energy expenditure, or the amount of calories you burn off: triiodothyronine (T3) and thyroxine (T4).
These thyroid hormones affect your basal metabolic rate (BMR – the energy required to keep your body alive), which makes up about 60-70% of the total amount of calories your body burns off per day. High levels of T3 and T4 can increase your BMR, and low levels can decrease your BMR.
Whoa…that sounds pretty significant, almost as if it’s the key to weight loss…right?? It’s tempting to draw that conclusion, but keep in mind that T3 and T4 are only two hormones out of many that are involved in metabolism.
In addition, these thyroid hormones are also involved in cell growth, protein synthesis and degradation, appetite and food intake, fat breakdown, heart rate, body temperature, reproductive function, and more.
These hormones can interact with almost every cell in the body, so a disruption in the production of T3 and T4 can lead to a variety of downstream effects.
How does the thyroid affect weight loss?
When your thyroid isn’t producing enough T3 and T4, everything in your body takes a dip in production. It’s like your laptop going into low power mode – it gets slower…and then you start yelling at the screen. This “low power” condition is referred to as hypothyroidism.
With this condition, your BMR can decrease upwards of about 20%, or even more. For an average female with a BMR of 1400 calories (women are more likely to suffer from low thyroid than men), that can mean a drop of 300 calories per day or more! This can definitely throw a wrench into your weight loss efforts.
However, along with that drop in BMR is a drop in appetite, decreasing your level of food intake. But that drop in food may not be enough to offset the drop in BMR, producing a net decrease in the amount of calories your body burns off per day. Due to this net drop in calorie burn, weight gain is a common symptom of hypothyroidism.
What’s intriguing is the amount of weight gain.
You may think it’s significant.
I did too.
But apparently weight gain from hypothyroidism is pretty modest, ranging between 5-10 lbs!
It can be more depending on the severity of the condition. A portion of this weight gain can also be attributed to excess salt and water retention. This just goes to show that there are bigger levers that influence our body weight, such as lifestyle factors that we are largely in control of.
Okay, so even though having less thyroid hormones isn’t the end of the world, it can still be demoralizing to know that your hard work isn’t getting the normal amount of payoff it usually would.
It’d be nice to have a motor revving at its expected RPM, or a phone battery that is running at 100% of its capacity. Plus, with the numerous processes that T3 and T4 are involved in, hypothyroidism can produce symptoms other than weight gain such as:
🔷 Energy Symptoms: tiredness, fatigue, lethargy
🔷 Mental and Emotional Symptoms: depression, irritability, brain fog, forgetfulness
🔷 Cosmetic Symptoms: dry hair and skin, brittle nails, yellowing of skin, thinning hair, hair loss, puffy face and hands
🔷 Reproductive Symptoms: menstrual cycle changes, fertility problems, low libido
🔷 Other Physical Symptoms: slow heart rate, cold intolerance, constipation, muscle cramping and weakness
If that list weren’t long enough, low thyroid can also increase the risk for larger health issues like elevated cholesterol, heart problems, nerve damage, infertility, miscarriages, and birth defects. Yikes!
Causes and contributors to hypothyroidism
Hashimoto’s Thyroiditis:
This is the most common cause of hypothyroidism. This is an autoimmune disorder where the immune system attacks healthy thyroid cells, thus lowering T3 and T4 production. The cause of Hashimoto’s disease is unclear. It may be related to genetic and environmental factors.
Surgical removal of the thyroid (thyroidectomy):
In cases where the thyroid is overactive, grows very large, or contains cancerous growths, a surgical removal of parts of, or the entire thyroid may be necessary.
Damage from radiation therapy:
Radiation from chemotherapy used to treat cancers located in the head or neck can damage the thyroid and surrounding tissues.
Long term use of oral contraceptives:
It appears that long term use of birth control pills (longer than 10 years) is strongly associated with hypothyroidism. Estrogen and progesterone in these pills can lower the amount of free thyroid hormone available in the blood.
Pregnancy:
Pregnancy may cause the thyroid to be overactive or underactive. Thyroid dysfunction occurs in about 2 to 3 pregnancies out of every 100.
Menopause:
It is common for middle aged women going through menopause to also have an underactive thyroid, although it’s not clear what role menopause plays in developing this condition (perhaps related to declining estrogen levels).
Obesity:
It appears that obesity and hypothyroidism are closely linked, with hypothyroidism seeming to be secondary to obesity. However, non-obese, lean people can have hypothyroidism too.
Goitrogens and mineral deficiencies:
Goitrogens are micronutrients found in cruciferous vegetables (broccoli, cabbage, brussel sprouts, etc.), some fruits, and soy products. They can prevent the thyroid from taking in iodine, a key mineral for thyroid health and function. This causes the thyroid gland to enlarge and form a goiter.
Even though this sounds bad, goitrogens are not a big risk factor, unless eaten in massive quantities, or if you already have an iodine deficiency. Also, goitrogens can be neutralized simply by heating and cooking your food. Several mineral deficiencies can disrupt proper thyroid function, such as:
Iodine
The thyroid needs iodine in order to create T3 and T4. Iodine is found in iodized table salt, seafood, dairy, eggs, and chicken.
The daily recommended intake is 150 mcg. Iodine deficiency is rare, but can potentially occur for people who don’t use iodized salt, pregnant women, and vegans.
Tyrosine
This is an amino acid (whoops, not a mineral) that is combined with iodine in order to create thyroid hormones. Tyrosine can be found in poultry, fish, nuts, dairy, beans and seeds.
Iron
Required for the production of thyroid stimulating hormone (TSH), which is released from the pituitary gland and signals the thyroid to create T3 and T4.
The daily recommended intake is 8 mg for men, 18 mg for women, and 27 mg for pregnant women. Iron is found in many vegetables, meats, eggs, seafood, beans, legumes, breads, and cereals.
Selenium
Helps the thyroid use iodine to create T3 and T4. The daily recommended intake is 55 mcg. For pregnant women it’s 60-70 mcg. Selenium is found in breads, cereals, poultry, red meat, seafood, eggs, and Brazil nuts.
Copper
Helps stimulate the production of T4, and also modifies calcium levels to prevent over absorption of T4.
The daily recommended intake is 900 mcg, and 1300 mcg for pregnant women. Copper is found in meat, fish, nuts, seeds, whole grains, and…wait for it…chocolate!
Zinc
Also needed for the synthesis of thyroid hormones. The recommended daily intake is 11 mg for men and 8 mg for women. Zinc can be found in meats, poultry, seafood, legumes, and whole grains.
How do I know if I have hypothyroidism?
Hypothyroidism is pretty common in the US. About 5% of the population over 12 years old have it. The American Thyroid Association estimates that there are 20 million people who have thyroid disease, and up to 60% of them are unaware of it.
Women are 5-8 times more likely to have thyroid problems than men, and 1 in 8 women will develop thyroid issues in their lifetime. If you suspect something is going on with your thyroid, go ask your doctor about getting your TSH levels checked.
As stated above in the iron section, TSH is what stimulates the thyroid to make its T3 and T4 hormones. In someone with low thyroid hormones, TSH is not taken in by the thyroid, and remains in the bloodstream. Therefore, they’d see an elevated TSH in their test.
The reference ranges for TSH is 0.4 – 4.0 milliunits per liter (mlU/L). Levels higher than 4.0 mlU/L may indicate hypothyroidism. There’s no harm in getting checked out! The certainty is worth it. You get to know for sure if your thyroid is getting in the way of your weight loss efforts.
I have hypothyroidism. What should I do?
Work with your doctor to figure out a treatment plan that works for you. With that being said, the most common treatment for hypothyroidism is thyroid hormone replacement with a medication called levothyroxine. This is a synthetic substitute for the T4 hormone.
Wait…what about T3? No worries, your body can convert T4 into T3, and your thyroid typically releases 20 times more T4 than it does T3. Levothyroxine is one of the most commonly prescribed medications in the US. About 7% of the population has a prescription.
Once your thyroid hormones are restored through medication, typically your BMR will rise back to its normal level. Therefore, your ability to lose weight will be restored as if your thyroid were working properly! Woot woot!
This is by no means a magic pill though, because weight loss from treating hypothyroidism is pretty modest – around the 10 lb mark. And it’s also not a guarantee, as there are many patients who do not experience any weight loss after restoring their thyroid hormone levels.
Again, there’s more to metabolism and weight loss than just the thyroid! Since a major cause of hypothyroidism is due to autoimmune issues, it might make sense to review your diet for any potential allergens or triggers for inflammation, like the following:
Foods that may increase inflammation:
🛑 Processed foods high in sugar
🛑 Refined carbs (white bread, pastas, etc)
🛑 Processed foods high in saturated or trans fats
🛑 Alcohol
Foods containing potential allergens:
🛑 Dairy, eggs
🛑 Fish, shellfish
🛑 Nuts, seeds, legumes
🛑 Grains, such as wheat
🛑 Certain vegetables and fruits
Experiment with removing these foods from your diet gradually, and then reintroducing them to see how your body responds. This process, also referred to as an elimination diet, can be useful to identify your unique food sensitivities and intolerances.
Those food lists are pretty broad and wide ranging, so it’s best to have a professional, like a registered dietician, aid you in this process. They may have insight on whether doing something like this is necessary for you. If you both choose to go down this route, they’d probably know where to start and how to move forward based on your health profile.
My overall thoughts and conclusions
Though hypothyroidism does slow the metabolism down, it seems the lowered appetite that comes along with it partially balances out the slowdown. This might explain why significant weight gain is not common with people with this condition, though it may be possible for severe cases.
Modest weight gains within the 5-10 lb range seem to be the most common. Even though it may not seem catastrophic , I totally understand that this additional weight is enough to cause distress. Also, it sucks having a slower metabolism…it definitely has a noticeable impact on your weight loss efforts!
I’m not a doctor, so don’t take my thoughts and opinions on what’s happening inside the body as fact. Which is why I recommend you go talk to your doctor, and ask if getting your TSH measured is right for you.
Hopefully it’s no biggie and they get it done for you so that you either get the treatment you need, or you get peace of mind knowing your thyroid is A-OK. Whether you have a thyroid issue or not, your best tools for weight loss are going to be the same old healthy behaviors that you’ve seen everywhere else:
✅ Eating mostly minimally processed whole foods, and limiting high fat, high sugar, high calorie processed foods
✅ Getting in regular physical activity
✅ Sleeping well for 7-9 hours a night
✅ Managing your stress
✅ Creating and maintaining a supportive environment
✅ Understanding the deeper reasons for why you’re doing this
✅ Being mindful of your thoughts about yourself, your body, and your journey
And lastly, keep an internal locus of control. I get that weight loss is hard, thyroid issue or not. And when things get hard, us humans have the tendency to blame things that are outside our control. I do this too, so I’m not pointing fingers!
We’ve got to do our best to resist this temptation, and focus on the things that we can control. Start with just one thing on the list above, and build on that! I hope you learned something new!
If you know a thing or two about the thyroid, and feel that there are improvements I can make on the information I’ve presented, please share! Email me at newton@newtonkwong.net. I’m always interested in learning more. Thanks for reading until the end, and see you in the next article!
Whoa you made it to the end!! Thanks for reading 🙂
If you found this article helpful, please check out my other ones!
Also, if you need help with any of the following:
⭐️ Losing weight ⭐️
⭐️ Gaining muscle ⭐️
⭐️ Managing your stress ⭐️
⭐️ Improving your nutrition ⭐️
⭐️ Increasing your daily energy levels ⭐️