The Connection Between Thyroid, Weight Gain, and Metabolic Health

An unexplained change in weight is one of the most common signs of a thyroid disorder. Weight gain may signal low levels of thyroid hormones, a condition called hypothyroidism. In contrast, if the thyroid produces more hormones than the body needs, you may lose weight unexpectedly combined with symptoms like palpitations and anxiety. This is known as hyperthyroidism. However, hypothyroidism, or an underactive thyroid, is far more common and a frequent cause of weight gain that occurs without obvious changes to diet or exercise routines. Thyroid is the hormone of metabolism. For many people with insulin resistance, when the cells of the body become numb to insulin, the thyroid does not function normally, leading to a greater risk of declining metabolic health. Indeed, high insulin levels in the blood may lead to a greater risk of thyroid proliferation and even represent a risk factor for thyroid carcinoma.

How Common Is Thyroid Dysfunction?

Approximately 60 to 70 percent of people with thyroid dysfunction don’t know they have it. For women, in particular, it can be difficult to get a diagnosis because symptoms are nonspecific and women are more likely to be dismissed, sometimes even gaslit by their doctor’s reaction. Women are seven times more likely to have thyroid dysfunction compared to men.

For women in North America, Hashimoto’s is the most common reason for low thyroid. Hashimoto’s disease is an autoimmune condition that involves thyroid dysfunction. Also known as autoimmune thyroiditis or “Hashi’s” for short, when you have Hashimoto’s disease, your body triggers an immune response in which antibodies are made that damage thyroid cells, resulting in low thyroid function over time. In other words, it’s a case of mistaken identity whereby your thyroid gets attacked by an overzealous immune system. This first causes an overproduction of thyroid hormones, then leads to an underproduction of those hormones because your thyroid has reached the “burnout” stage.

Loss of metabolic health is even higher. In one study from the University of North Carolina, 88 percent of US adults were metabolically unhealthy.

Hypothyroid Signs and Symptoms

When a patient comes to see me who has unexplained weight gain or weight that never seems to drop despite doing all the ‘right’ things, the first thing I think of is a thyroid issue. I run through my thyroid questionnaire with the patient. Below are some of the questions I ask. You can go through them one by one and see how many you answer yes to. You can also find these questions and more in my book THE HORMONE CURE.

• Have you gained weight?
• Do you have 20 pounds that you just cannot lose?
• Have you noticed any changes in your hair, nails, or skin?
  • Hair loss, including the outer third of your eyebrows and/or eyelashes?
  • Dry skin?
  • Dry, straw-like hair that tangles easily?
  • Thin, brittle fingernails?
• Have you been unusually tired or sluggish?
  • Do you notice slow speech, perhaps with a hoarse or halting voice?
  • Have you been told you have a slow heart rate?
  • Do you experience lethargy where you feel like you’re moving through molasses?
  • Do you experience fatigue, particularly in the morning?
  • Do you think your brain is slowing, with slow thoughts?
  • Do you have difficulty concentrating?
  • Do you have sluggish reflexes, diminished reaction time, even low sex drive?
• Have you noticed any bowel changes? This will usually be more constipation as thyroid hormones are involved in peristalsis or movement of the intestines.
• Are you always cold?
  • Do you have a tingling in your hands or feet?
  • Do you have cold hands and feet or cold intolerance?
  • Do you have heat intolerance?
  • Do you have sensitivity to cold? You may shiver more easily than others and are always wearing more layers than others, or wearing socks to bed.
• Have you been especially moody? Small changes in thyroid levels can cause dramatic changes in mood and mental state. Every patient with depression and anxiety should have their thyroid panel checked.

If you have five or more symptoms, you probably have a thyroid problem. Doctors may write you off but stand your ground. Three or more symptoms can also mean you may have a thyroid issue. I recommend asking your doctor to check your thyroid, particularly to measure TSH, T3, and reverse T3. According to American Thyroid Association, a standard range of TSH levels should be 0.4 to 4.0 mIU/L. However, in my experience, people with normal thyroid function have a TSH of 0.3 to 1.5, so my goal is less than 2 in most of my patients.

Testing Your Thyroid

One simple way to check your thyroid at home is with a mirror and a glass of water. I am a big fan of self-testing. Self-tests are so empowering. The biggest problem with thyroid is that 60-75% of people with thyroid dysfunction don’t know they have it. Yet, when they go to their doctor, their doctor doesn’t test. Therefore, having tools like this puts the power in the hands of patients.

Take a hand mirror. With your face close to the mirror, focus on the lower front area of your neck, above the collarbones, and below the voice box (larynx). If you run your fingers down your throat starting at your chin, you will feel the hard thyroid cartilage. In men, this is called the Adam’s apple. Right below that you will find the thyroid. It’s a butterfly-shaped gland.

Your thyroid gland is located in this area of your neck. While focusing on this area in the mirror, tip your head back. Take a drink of water and swallow. As you swallow, look at your neck and watch for the thyroid moving up and down. Check for any bulges or protrusions in this area when you swallow or any asymmetries. There are no definitive guidelines for how often to do this test but I recommend to do this test about every six months after age 30.

I sometimes recommend home thyroid test kits, especially during the pandemic when people were not comfortable going to the lab. In my opinion, doctors are not testing enough. Home test kits are empowering and they can give you a way to talk with your doctor. However, we don’t know who is interpreting the results and the accuracy of the tests so we do need to be cautious using them. A blood draw at a lab is still the gold standard.

What 3 Mistakes May Be Affecting Your Thyroid?

There are three main mistakes that my patients make when it comes to their thyroid.

1. Too much or too little iodine.

One cause of thyroid problems is getting too much or too little iodine. Iodine is tricky because the therapeutic range is very narrow. Bottom line: iodine slows down the thyroid. Many of my patients are taking iodine in their multivitamin or as another supplement and don’t realize it’s worsening their thyroid function, and we have to perform an iodine detox. I advise checking your multivitamin to see if it includes iodine. Because of the risk of iodine overload, I recommend that you only get iodine from food sources, like seaweed, seafood, eggs. While table salt is a common source of iodine, for some people, table salt contains too much of it. I recommend sea salt because of the narrow health range. I prescribe Himalayan or Maldon sea salt.

2. A carb intake that is too low

Women who are trying to lose weight will often choose a very low-carb diet, for example, the classic ketogenic diet. When you restrict carbs excessively it leads to rapid water weight loss but the carb restriction can affect levels of the thyroid hormone, reverse T3. Reverse T3 (rT3) is an inactive metabolite of T4 and provides a mechanism to slow down metabolism in order to save energy. It provides a feedback system to keep you in balance under normal conditions. However, if your body is stressed or on a calorie-restricted diet, a signal is sent to change the ratio, and you produce more reverse T3 and your metabolism slows.

3. Ignoring insulin and metabolic health

The two most common hormone imbalances that I see in my patients are hypothyroidism and insulin resistance. As described earlier in the article, they tend to go together. In my medical practice, I emphasize the importance of addressing both issues in order to heal.

What Can You Do?

In my new book WOMEN, FOOD, HORMONES I share a four-week modified ketogenic food plan. The protocol recommends less than 25 net carbs per day. I like people to focus on net carbs, carbs from vegetables. After four weeks I recommend increasing carbs by five grams a day and seeing how their body weight changes. I encourage women on the plan to eat plenty of prebiotic carbohydrates and help them explore what their carbohydrate tolerance is as a way of helping with their thyroid function.

If you’ve tried keto before and found it didn’t work for you, my modified ketogenic diet plan offers a potential solution. Remember, women are more sensitive to carbohydrate restriction and calorie restriction than men are; these restrictions may activate an alarm that shuts down menstruation and increases inflammation—and may explain why so many women on keto lose menstrual regularity. Experts suggest that, compared to men, women are more likely to experience a plummet in blood sugar on keto. Maybe a combination of these issues causes the problem. Additionally, women in perimenopause and menopause are more likely to have hypothyroidism. My recommendation, whether you are still cycling or not, is to adapt the ketogenic diet as described in my new book.