If you know anything about body composition and fat loss, you are aware that hormones play a pivotal role. A lot of people just focus on carbs, calories, or exercise when trying to lose body fat, but to get lasting results, you need to take a wider view and account for hormones.
One of the most important group of hormones when it comes to body composition is those produced by the thyroid gland. Thyroid hormones regulate metabolic rate, influence energy levels, and impact a cascade of other hormones that play a critical role in health and function.
What Is The Thyroid?
The Thyroid is a small butterfly-shaped gland in the front of the neck. It is best known for regulating metabolic rate by affecting enzyme activity, body temperature and energy levels. The thyroid is also involved in growth, development, heart function, and central nervous system activation.
How It Works: Thyroid hormone balance is a complicated process whereby the hypothalamus in the brain puts out Thyroid Releasing Hormone (TRH) telling the pituitary gland to release Thyroid Stimulating Hormone (TSH). TSH stimulates the thyroid gland to release T3, the active form of thyroid hormone, and T4, the inactive form of thyroid hormone. T4 is turned into T3 by the liver and kidneys. This interrelationship between T3 and T4 is one example of how changes in hormone levels affect each other in a cascade-like fashion.
The thyroid works on a negative feedback loop and as T3 and T4 go up, they send a message to the hypothalamus and pituitary to reduce TRH and TSH, allowing thyroid activity to slow. Vice versa as T3 and T4 drop, TRH and TSH go up, allowing for a stronger message to the thyroid to release T3 and T4.
There are two ways that thyroid function can be compromised:
Hyperthyroidism occurs when the thyroid is overactive and too much thyroid hormone is released, increasing heart rate, raising body temperature, and triggering appetite. People with hyperthyroidism have a hard time sustaining body weight, which might sound favorable in a fat-loss obsessed nation, but it drastically reduces quality of life, often leading to insomnia, irritability and muscle wasting.
Hypothyroidism occurs when the thyroid activity is reduced and too little thyroid hormone is produced. It is associated with decreased body temperature, lower metabolic rate, increased body fat, and chronic fatigue.
How Do Thyroid Hormones Influence Body Composition?
Thyroid hormone plays an integral role in regulating body composition by influencing the number of calories the body burns daily. For our ancestors, when food was scarce, one of the main jobs of the thyroid was to respond to a decrease in energy intake and slow metabolic rate to prevent the loss of lean tissue.
In modern times, when most people have excess body fat and ample food available, the thyroid still responds in the same way. When people diet, lowering calorie intake, thyroid activity will slow and thyroid hormone will go down. Body temperature drops so that the body burns fewer calories, leading to a plateau in fat loss.
What Else Causes Hypothyroidism?
Dieting isn’t the only thing to lead to decrease in thyroid hormone. Because thyroid hormones are intricately related to balance of other hormones, including cortisol, insulin, leptin, and androgens, many lifestyle and nutritional factors can impact thyroid function. Therefore, it’s important to take a holistic approach to solving thyroid issues and look at the big picture of hormone balance.
This is critical because in some cases, the thyroid is more of a bystander and not the root cause. Generally, when this is the case, thyroid function will be low and symptoms will be present but lab tests will appear normal. The medical term for this scenario is subclinical thyroid condition. The gland is working, but thyroid hormone is not able to exert its positive effect on target tissues, leading to symptoms and a poor quality of life. What follows is a list of five of the most common thyroid disruptors with solutions.
#1: Excess Stress & High Cortisol
When you suffer stress, the adrenal glands pump out the stress hormone cortisol, raising blood sugar so that you have the necessary energy to get you through the stressful situation. High cortisol output places an excessive burden on the pituitary gland, blunting the messages of Thyroid Stimulating Hormone and leading to lower release of T3 and T4. Cortisol also inhibits conversion of inactive T4 to active T3 by the liver.
Fix It: Take note that when stress causes hypothyroid symptoms, it’s not a problem with the thyroid gland itself. The thyroid is still capable of producing thyroid hormone, but it is not responding effectively to the hormonal cascade telling it to do so due to an excessive stress response. Therefore, the solution is to develop a stress management plan to reset the hypothalamic-pituitary axis and lower cortisol, restoring the thyroid hormone cascade. Actions like regular exercise, adequate sleep, deep breathing and meditation, and a healthy diet will all help balance cortisol and restore thyroid function.
#2: Blood Sugar Irregularities
For most people, dealing with their stress is hard. After all, you probably have little control over the length of your commute, anxiety about your job, or your never-ending to-do list. The good news is that diet is one area you can control and it has a powerful impact on lowering stress and improving thyroid function.
The body tries to regulate blood sugar levels in a specific range because when blood sugar drops too low, you can experience seizures, coma, or even death. The body does this via insulin, the hormone responsible for storing blood sugar and maintaining glucose at healthy levels. However, when you combine a carbohydrate-rich processed food diet with lack of physical activity, cells become resistant to insulin, which leads the body to pump out more insulin than is necessary, triggering peaks and valleys in blood sugar.
When blood sugar is irregular, cortisol levels increase as the body attempts to maintain energy levels, inhibiting proper release of TSH and conversion of T3.
Fix It: Ideally, you want your fasting blood sugar (your blood sugar level when you haven’t eaten for 8 hours) to be between 75 and 95 mg/dl. To achieve this, you need a combination of exercise and healthy diet: Strength training, intervals, and aerobic training all have a profoundly beneficial effect on blood sugar, automatically sensitizing cells to insulin and adding new insulin receptor sites. Try to do some form of exercise daily, while being as active as possible throughout the day.
A higher protein, lower carb diet that prioritizes whole foods is your best bet for restoring insulin sensitivity and balancing blood sugar. Plan meals around high-quality protein (meat, eggs, dairy, fish, or beans), a leafy green vegetable, and healthy fat (nuts, avocado, or the fat naturally occurring in your protein source). Include starchy vegetables, fruit, and whole grains, depending on body composition and activity levels.
Ask a mainstream health practitioner the solution to obesity and they will very likely tell you to “eat less and move more.” Unfortunately, this approach ignores how hormones function in obesity.
It all starts with the hormone leptin. Leptin is a hormone that is secreted by body fat, giving the brain a message that you’re “full” and don’t need to eat as much. Lower food intake slows your metabolism, which signals your hypothalamus to make TRH, triggering TSH release from pituitary, which tells the thyroid to make thyroid hormone.
In obesity, this message stops functioning. The brain becomes resistant to leptin’s message and you experience chronic hunger. Leptin resistance makes the hypothalamus believe that you don’t have adequate calories coming in even if you have abundant body fat and are eating to excess. Because your brain “thinks” you’re in “starvation mode” with inadequate calorie intake, it slows down thyroid hormone production—TSH goes down, as do T3 and T4. Appetite increases, fat breakdown slows, and insulin resistance increases.
Fix It: Your overall goal to combat obesity is to create an energy deficit by making better nutrition choices and training properly.
Solving leptin resistance should start with regularly planned high-protein, vegetable filled meals that focus on mindful eating and listening to your body’s hunger cues. Shifting away from processed foods and carbohydrate-centric meals is necessary to allow blood sugar to stabilize, and insulin and cortisol to go down.
Second, adopt a regular workout program to improve lean mass and increase the body’s ability to burn body fat. Be sure to do the little things that promote fat loss such as getting adequate sleep, being active throughout the day, and minimizing stress.
Obesity and unbalanced hormones have one thing in common: Inflammation. Anytime you have fat gain, elevated cortisol, insulin resistance, or thyroid dysfunction the body releases inflammatory compounds that cause chronic inflammation, damaging tissue and further dysregulating hormones.
Interestingly, when balanced, thyroid hormones have a protective role against oxidative stress and inflammation. However, poor diet, obesity—especially the accumulation of belly fat—chemical exposure, and a sedentary lifestyle can all increase inflammation. In this environment, something called “tissue hypothyroidism” occurs in which T4 is not effectively converted to T3.
Known as Nonthyroidal Illness Syndrome (NTIS), TSH levels will be in normal range, which can lead doctors to miss it as thyroid dysfunction. Normally, T4 is converted to T3 by deiodinase enzymes. Inflammation can reduce deiodinases, causing low T3, which in turn leads to more oxidative stress and inflammation. NTIS is considered “an adaptive response” to high levels of inflammation rather than true hypothyroidism. It’s also hard to diagnose: TSH and T4 will be normal, but T3, which mainstream doctors often won’t test for, will be low.
Fix It: Just like all of our other solutions, lowering inflammation starts with diet, fitness, and lifestyle. Strength training lowers markers of systemic inflammation, while improving the body’s ability to counter oxidative stress. Lifestyle actions such as mediation, lowering chemical toxin exposure, and getting adequate sleep also decrease inflammation.
Most important: Lowering refined carbs and processed foods in favor of antioxidant-rich foods (berries, leafy greens, beans, nuts, seeds, and almost all vegetables) will help the body eradicate inflammation. Additionally, dark chocolate, seafood, coffee, tea, and probiotic foods like sauerkraut and fermented dairy will provide nutrients that help to counter oxidative processes in the body.
#5: Unhealthy Gut
If you know anything about gut function, it’s probably that there are a gazillion bacteria living in the GI tract. Some of these bacteria are beneficial and some are harmful. One little known role of the gut bacteria is to assist with conversion of inactive T4 into the active T3 thyroid hormone. The gut bacteria release an enzyme called intestinal sulfatase that allows for T4 to be converted to T3 in the GI tract. This is one reason why people with poor gut function may have thyroid symptoms but normal lab results.
Inflammation in the GI tract also raises cortisol, which you already know inhibits release of thyroid hormone and impedes the T4 to T3 conversion.
There are other ways unhealthy gut bacteria can impact thyroid function: They can cause constipation, which impairs clearance of estrogen from the body. Excess estrogen raises thyroid-binding globulin (TBG), a hormone that binds to thyroid hormone, decreasing its availability to target tissues in the body. Conversely, low thyroid function, reduces transit time in the gut, causing constipation, inflammation, and reducing absorption of nutrients.
Fix It: Healing your gut starts with what you put in it: Instead of processed foods and refined carbs, favor fiber-rich fruits and vegetables. Avoid foods that you are intolerant too—these will be individual but common food intolerances are dairy, eggs, gluten, and other grains.
Get adequate protein to ensure complete detoxification. Take a high-powered probiotic that is guaranteed through the date of expiration. Try supplementing with resistant starch to promote proliferation of healthy gut bacteria. Consider taking glutamine and glycine to health the intestinal cellular lining.
Final Words: Hopefully you noticed that these five conditions that affect thyroid function aren’t originating with your thyroid. Something is going wrong in another part of your body and it is negatively impacting thyroid function. In most cases, thyroid medication isn’t necessary. Solving the problem at its source will allow your thyroid to come back into balance.