3 Ways Dieting Can Cause Hypothyroidism

When I was struggling with chronic dieting and disordered eating, life was a lot less fun than it is today. There were lots of reasons for this—mental, emotional, spiritual, social, physical—many of which I’ve already discussed on this blog. But today, I’m going to touch on some of the physical reasons.

Dieting made me physically ill, even when I was at a “normal” weight. My stomach was constantly in pain, my periods were irregular, and I was cold all the time. My struggles with food and exercise affected nearly every system in my body. I’ll be diving into the the details of those systems in future posts, but today I’m going to be talking about how dieting caused me to suffer from hypothyroidism. I’ll also explain some of the other ways that dieting can cause hypothyroidism (outside of my own experience) and what you can do about it if you’re in a similar boat.


Hypothyroidism and Eating Disorders

The most ironic part of this story is that I used to wish I had hypothyroidism. It’s not that I wanted to experience thinning hair, fatigue, irregular cycles, or depression. Really, I already was struggling with those things, and hopefully a diagnosis of hypothyroidism would give me some answers. (Mind you, I was in denial about my eating disorder at the time, which was really at the heart of my symptoms.) Honestly though? I hoped that convincing my doctor I had hypothyroidism, and the subsequent prescription for thyroid medication, would help me lose weight—something I’d been struggling to do, ever since I’d started binge eating.

When my doctor told me that my thyroid labs were, in fact abnormal, I was relieved. But soon after she started speaking, my heart sank.

“The good news is,” Dr. H noted, “Your hypothyroidism is caused by stress, not a problem with your thyroid gland itself, so you don’t need medication.” I tuned out the rest of what she said. Of course I’m stressed, I thought, frustrated that I wouldn’t be getting the ‘weight loss pill’ that I hoped for.

Eating disorders have a funny way of hiding in plain sight.

The thing is, thyroid medication isn’t a weight loss pill—it’s a hormone, and prescribing it to patients who don’t need it is extremely dangerous. I now know that my doctor was right to withhold the prescription, and I really wish that she had dug a little deeper to find the red flags in that stress-induced hypothyroidism diagnosis. Sure, I was a college student (stress) living in a new city (stress) away from family (stress) with social anxiety that was interfering with my ability to make friends (stress). But the pink elephant that was somehow hiding in plain sight was my eating disorder, which created not only psycho-emotional stress, but also significant biochemical stress in my body. The dysfunction indicated on my thyroid labs was only one of the many ways that my body was falling into disarray because of the extreme ways I was eating and exercising.


The interplay between stress and thyroid function is complex and nuanced, and is much more than can be reasonably summed up in a single post. (I’d need a whole blog about just that one topic!) In this post, I’ll be giving an overview of three main ways that dieting and disordered eating can lead to hypothyroidism below, but if you want to dive deeper, check out these posts:


1) Stress-Induced Hypothyroidism

Really, most conditions that afflict the human race are triggered by stress. Whether it’s an acute illness, like the flu, or a chronic disease like diabetes, stress plays a role. In the case of a cold, stress lowers the body’s immune system enough that it can’t overcome the viral exposure. With diabetes, long-term exposure to stress taxes the body’s ability to regulate metabolism, and systems start to break down. With hypothyroidism, stress can cause problems in a few different ways, both directly and indirectly. Let’s start with the direct route, which was what I dealt with, personally.

When the body isn’t getting enough food (or has inconsistent access to food…ie disordered eating), it goes into ‘survival mode.’ You might have heard this described as ‘starvation mode’ and basically it refers to the phenomenon that takes place in which the body slows down the metabolism (rate of energy use) in order to, well, conserve energy. It makes a lot of sense if you think about it, and follows the same principle of financial budgeting that we use in our own everyday lives: if resources run low, cut down on expenditures…or else.

In a healthy, functioning system, the brain and thyroid gland talk to each other in order to regulate the proper amount of thyroid hormones to produce. Parts of the brain called the hypothalamus and pituitary gland work together to signal to the thyroid gland how much thyroid hormone to make. As thyroid hormone circulates in the blood, the brain assesses the status quo of the body in relation to the present levels of thyroid hormone and makes a decision about whether the levels are appropriate. It uses this information to tweak its signaling to the thyroid gland about whether to ramp up or down its activity. The communication between the brain and the thyroid is a series of checks and balances.

Thyroid hormone comes in two main forms, T4 (the ‘storage’ form) and T3 (the ‘functional’ form). T3’s job is to float around in the blood stream and bind to receptors on cells, whereas we typically understand that T4 waits around until more T3 is needed, in which case it gets converted into T3. However, during that conversion of T4 to T3, some of the T4 also is converted into another form of hormone called reverse T3. It looks just like T3 but is inactive. If cells are like door locks and T3 is the key, reverse T3 (rT3) fits into the lock perfectly but can’t turn the deadbolt. As a result, T3 can’t fit into that lock, and T3 is prevented from doing its job. Some rT3 is normal, but too much rT3 is not.

During periods of chronic stress, especially the kind caused by irregular eating patterns and dieting, the brain tones down its signaling to the thyroid, telling it to produce less hormone so it can decrease metabolic rate and conserve energy use. At the same time, the conversion rate of T4 into T3 decreases, and more T4 is converted into rT3. As a result, the thyroid produces a less than normal amount of hormone (hypothyroidism) and the function of the thyroid hormone is decreased in the body (functional hypothyroidism).

2) Sex Hormone Imbalances (Estrogen Dominance)

Okay, so earlier when I said that T4 and T3 just float around in the blood stream waiting to be used? That wasn’t the full story. Instead, thyroid hormone travels in the blood stream attached to a protein called Thyroid-Binding Globulin. In fact, most hormones don’t just float around in the blood, and instead ride around on globulin proteins, like a person driving a car, or riding a bus. When there’s more thyroid hormone produced than there are seats on the thyroid-binding globulin “bus,” then the T3 can do it’s job of binding to cells.

However, certain conditions can cause a higher-than-normal level of thyroid-binding globulin to be produced. In these situations, the globulin binds up all the “free T3,” preventing it from doing what it’s supposed to be doing. One of the more common reasons for elevated levels of thyroid binding globulin (TBG) is high levels of estrogen in the blood.

I won’t get into the mechanism for how, exactly, estrogen elevates levels of TBG, but there are three main reasons for elevated estrogen: use of estrogen replacement therapy (as in menopause), use of estrogen-containing oral contraceptives (i.e. birth control pills), and estrogen dominance. As we discussed in this post, crash diets and disordered eating are a huge driver of estrogen dominance.

3) Hashimoto’s Hypothyroidism

The ins and outs of Hashimoto’s will come in a different post at a different time, but here’s a general overview:

Hashimoto’s is an autoimmune disease in which the body mistakes the thyroid gland tissue as a foreign invader and starts producing antibodies against it. This creates inflammation and tissue damage, harming the thyroid gland’s ability to produce adequate levels of thyroid hormone. As a result, thyroid hormone levels drop and the patient ends up suffering from hypothyroidism.

Like other autoimmune diseases, stress is the #1 trigger of onset of the disease and of symptoms. This stress can be emotional, psychological, or physical, such as the form caused by an illness, overexertion, or—you guessed it—dieting.

Healing from Stress-Induced Hypothyroidism

Recovering from—or rather, managing—hypothyroidism really depends on the root cause of the thyroid dysfunction. If the cause is completely stress-dependent, as was my case, healing means addressing the complex web of factors that contributed to that stress. For me, it meant working with a therapist and trained nutrition professionals to heal from my eating disorder and start taking care of my mind, body and spirit. However, hypothyroidism with an autoimmune component (i.e. Hashimoto’s) or the type induced by imbalances in sex hormones (i.e. estrogen dominance) would look somewhat different.

The common denominator among all holistic treatments, though, is to start at the beginning. Healing hormone imbalances requires a firm foundation of a well-balanced lifestyle. This includes eating enough food, identifying and correcting nutritional deficiencies, getting enough sleep, exercising in moderation, managing stress, and having a solid support network.


For more details on how to put together the building blocks of hormonal health, check out this post: 5 ways to balances hormones, naturally.


The main takeaway from this post is that dieting is harmful, eating disorders are dangerous, and restoring your relationship with food and your body is quite literally a life-and-death situation. If you’re struggling in your relationship with food, my new book Fulfilled is for you. It dives into the nitty gritty details of healing so that you can let go of shame, embrace your appearance, and eat the food you love. Fulfilled is available for pre-order at AmazonBarnes & NobleIndieBound, my publisher’s website, or any online or retail shops where you usually buy books!



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