Avoid The Carnivore Diet If You Have Thyroid Problems

There are so many different diets and foods that you can eat as a thyroid patient that it can make it hard to navigate this space.

One thing is for certain, though:

The food that you put into your body can either exert a positive effect on your body and thyroid, or a negative one. 

Your job as a thyroid patient is to put as many foods into your body that continually provide a positive stimulus. 

If you can repeatedly do this over a long period of time then, yeah, you might put yourself in a situation where you are less dependent on thyroid medication. 

And, intuitively, a lot of people know that this is true (even if their doctors try to convince them otherwise) which is why you’ll find all sorts of information on the internet about which diet is best. 

One of the diets that is often touted as a cure-all to everything is the carnivore diet. 

Proponents of this diet suggest that going carnivore and eating like our ancestors has the ability to put multiple diseases into remission, help with weight loss, and more. 

But is this really true? And is this the type of diet that you should consider as a thyroid patient? 

My response? 

No. 

At least not for everyone. 

Will there be situations in which going carnivore makes sense or in which some people will see benefits by going carnivore? 

Of course, because everyone is unique there is no one-size-fits-all diet. 

But does this mean that carnivore should be the recommended base diet for all thyroid patients and all thyroid problems? 

Definitely not. 

If you are thinking about going carnivore and you have a thyroid problem, here are a few things you should consider before going down the rabbit hole of carnivore: 

#1. Carbohydrates Are Needed For Optimal Thyroid Function

I think everyone is familiar with what the carnivore diet entails but, in case you aren’t, here’s a quick primer: 

The carnivore diet is a diet that focuses primarily on meats but also allows fish and other animal products such as eggs and butter. 

This diet is very high in protein and fats but is severely lacking in carbohydrates which is by design. 

Many people, especially those who are proponents of carnivore and the ketogenic diet, suggest that carbohydrates are responsible for the diseases that plague mankind. 

According to them, diseases like cancer (1), diabetes (2), heart disease (3), stroke (4), and more, all stem from the increased intake of carbohydrates like sugar, bread, pastries, pasta, and so on. 

This stance is represented in the diet and foods that people who believe this recommend. 

In other words, they will strongly suggest that you remove all sources of carbohydrates from your diet as possible. 

They justify this stance by making the claim that carbohydrates are considered non-essential which is not true for fats and proteins. 

As far as nutrition goes, the body has an absolute need for fats, called essential fatty acids (5), and proteins called essential amino acids (6). 

Because the body is unable to produce these essential fats and proteins, they must be consumed from your diet. 

You’ll notice that there are no essential carbohydrates. 

So the logic goes that you will be able to get everything your body needs if you consume a diet that is rich in essential fats and essential proteins. 

While this is technically true, there’s a little more to the story. 

The body doesn’t have a need for carbohydrates to survive, that much is true, but it appears to need carbohydrates to thrive. 

For the purpose of living a long and healthy life, most of us really want to thrive, not just exist, so this is actually very important. 

In women, low-carb diets have been shown to cause issues with the menstrual cycle and, in men, they’ve been shown to cause low testosterone. 

But more important than this, very low-carb diets sustained over a long period of time have been shown to cause thyroid problems in some people. 

This is seen in studies such as this one (7). 

What researchers see is that as carbohydrate intake decreases, the conversion of active thyroid hormones decreases as well.

This is reflected in thyroid lab tests as a decrease in active T3 thyroid hormone and an increase in T4 levels which is associated with no change in the TSH. 

If you aren’t familiar with thyroid hormone lab tests, allow me to explain what this means: 

The TSH is a measure of total thyroid function in the body.

So at first glance, the fact that the TSH remains unchanged in these diets is a fairly positive sign. 

But the problem isn’t from the TSH, it comes from the change in circulating thyroid hormones and their relation to one another. 

T4 is considered an inactive thyroid hormone which acts as a reservoir for T3 hormone production. 

T3, on the other hand, is the most biologically active thyroid hormone and the thyroid hormone that pretty much does everything you want your thyroid to do. 

What your body does is draw upon your T4 stores to turn it into T3 on an as-needed basis. 

The shift that is seen in low-carb diets indicates that the body is conserving T4 levels and reducing the conversion of inactive thyroid hormone to active thyroid hormone. 

This exact scenario is typically seen in situations in which the body is actively trying to conserve energy and shunt resources to other parts of the body that need those resources more. 

We see this lab pattern in situations where people are chronically ill or under extreme stress. 

In other words, low-carb diets, at least for some people, seem to cause changes in thyroid thyroid lab tests that are not usually seen in healthy people. 

The advocates of carnivore are aware of this but will try to suggest that these changes in thyroid hormones provide some benefit to longevity and may just be an adaptive response.

It’s hard to know exactly what these changes mean but there’s no question that, at least for some people, going carnivore may be enough to not only make existing hypothyroid patients feel worse but also enough to throw some people into hypothyroidism. 

This doesn’t mean that low-carb diets will negatively impact everyone who goes carnivore, but it does mean that it may cause problems for certain individuals. 

We’ll talk more about when it may make sense to accept these changes to thyroid function in a minute but for now, let’s talk about another reason you may want to avoid going carnivore: 

#2. Decreased Carbohydrate Intake Increases Sex Hormone Binding Globulin And Decreases The Activity of Sex Hormones

Not only will decreased carbohydrate intake impact your thyroid hormone levels, but it also will impact your sex hormone levels. 

We know this from both real-world examples of people who have shared their lab work (more on this below) while undergoing the carnivore diet and from research studies. 

They all show the same thing:

As carbohydrate intake declines, sex hormone binding globulin levels increase (8), and free sex hormone levels decline. 

For those who have never heard about sex hormone-binding globulin before, here’s what you need to know. 

Sex hormone-binding globulin (abbreviated as SHBG) controls how much sex hormone your body has available for use. 

The higher your SHBG is, the less active your sex hormones will be. It’s that simple. 

People who undergo low carbohydrate diets will see their SHBG rise which is automatically associated with a decline in free sex hormone levels. 

For men, this is seen as a decline in free testosterone and, for women, it’s seen as a decline in free estradiol. 

The impact on both hormones is the same for both genders, it’s just that the physiologic impact differs because men need testosterone more than women and women need estrogen more than men.

But why does this matter for thyroid patients?

Well, aside from the fact that sex hormone balance is critical if you want to live a long healthy life, there is also a bi-directional relationship between sex hormone levels and thyroid function. 

Thyroid hormones impact sex hormones like testosterone and estrogen (9) such that when thyroid hormone levels are low, men and women experience problems related to their primary sex hormone. 

Men will see a decline in libido, erectile dysfunction, low testosterone, and decreased vitality. 

And women will see changes to their menstrual cycle, weight gain, decreased libido, and infertility. 

In men, these symptoms are related to low testosterone and in women, they are related to low estrogen. 

As estrogen levels decrease they impact the thyroid by impacting thyroid-binding globulin (10). 

This impact can be significant enough to warrant higher doses of thyroid medication to normalize thyroid hormone levels in women. 

The bottom line? Thyroid hormone and sex hormones are connected. 

Outside of these theoretical changes seen in research studies, we also have some real-world examples of what these changes look like from long-term users of the carnivore diet. 

Dr. Paul Saladino M.D., a big proponent of the carnivore diet, has gone on record by sharing his lab work while on the carnivore diet and after the introduction of carbohydrates like fruit and honey. 

What he shares tracks exactly with the research stated above: 

His lab work after being on a strict carnivore/keto diet for several years showed a sky-high SHBG level, a low free testosterone level, a high-normal TSH, and a low T3. 

After adding fruits and honey to his diet (around 200 grams per day) he saw a very large drop in his SHBG level (by about half), a rise in his free testosterone level, a decrease in his TSH level, and a rise in his free T3. 

These changes were also associated with an increase in his energy levels and an increase in his basal body temperature. 

What’s even more interesting is that all of these changes occurred without impacting his fasting serum insulin level which remained undetectable both before and after. 

Why is this significant?

Because, at least anecdotally, it shows that carbohydrates are not only essential for proper thyroid and sex hormone function, but that including healthy sources of carbohydrates does NOT have a negative impact on insulin levels. 

#3. There are Better Ways To Lose Weight

I think one of the main reasons that the carnivore diet is so attractive to people is that 1) it’s relatively simple to understand and 2) there’s a promise of weight gain at the end. 

This is particularly appealing to thyroid patients who often struggle to lose weight. 

But is there anything special about the carnivore diet that you can’t obtain with other healthy diets?

No. 

Some people will try to suggest that carnivore diets are superior to weight loss because they result in more rapid weight loss. 

And while this appears true, it’s somewhat misleading. 

The weight loss associated with low carbohydrate diets will always be more rapid, at least initially, because these diets impact fluid levels as well as bowel movements. 

An increase in bowel movements and changes to the kidneys that result in the excretion of water from the body make it look like you lose a lot of weight quickly but this weight is just fluid and water, not fat. 

When you break down the weight loss from the carnivore diet and account for this loss in fluid, you see that there are no differences in other diets. 

It just appears to be more effective because the weight loss on the scale from fluid loss is more pronounced in the beginning. 

The reality is that you can absolutely lose weight at the same rate as the carnivore diet with a healthy whole food-based diet. 

And these whole-food diets that include healthy sources of carbohydrates such as fruits and vegetables do not come with all of the baggage and potential problems as the carnivore diet. 

In other words, there’s nothing special about the carnivore diet when it comes to weight loss. 

#4. Low Carb Diets Cause Sleep Disturbances

The final nail in the coffin for the carnivore diet is that it may cause issues with sleep. 

This particular issue is well-known in the carnivore community and is often referred to as carnivore insomnia or keto insomnia. 

Its exact cause is not exactly known but it definitely has something to do with carbohydrate intake. 

Studies like this one have shown that low-carb diets reduce rapid eye movement sleep and increase slow-wave sleep (11). 

Why is this a problem?

Because thyroid patients already suffer from shorter sleep duration and lower satisfaction with their sleep quality compared to the average population. 

When you add on additional factors that may make sleep worse, you have a recipe for even worse sleep outcomes. 

We also know that sleep plays an important role in regulating weight, thyroid hormones, and even sex hormones. 

So anything that negatively impacts your sleep will also impact these important systems.

Just because carnivore can cause sleep issues doesn’t guarantee that it will in your specific situation but because of the importance of sleep in your overall health, this factor should be considered, especially if you already have issues with sleep. 

Going Carnivore If You Have a Thyroid Problem: When Does it Make Sense?

Are there situations in which it may make sense to use the carnivore diet if you have a thyroid problem?

Absolutely. 

It may seem hypocritical for me to suggest this given what we’ve discussed so far but I do think there are situations where this diet does make sense, at least temporarily. 

The situations that I’m referring to are those of autoimmune diseases like Graves’ and Hashimoto’s and those with a combination of thyroid disease and diabetes. 

Let’s talk about the autoimmune diseases first: 

The reason I think it may make sense for those with autoimmune thyroid disease to give this diet a try is because there are so few treatments available for these conditions. 

I’m not saying that carnivore is the best diet for these conditions given that other diets like the AIP diet have been shown to be effective as well, but it is a really simple and easy diet for the average person to wrap their head around. 

Comparing the AIP diet to the carnivore diet is night and day. 

AIP requires a more thorough understanding of food and nutrition and it may not be as accessible to people who are not as well versed in nutrition as others.

Carnivore, on the other hand, can be simplified into a few sentences which means there may be more patient compliance with this type of diet. 

Again, that’s not to say that other diets can’t or won’t work for thyroid autoimmune disease, because they can, but simplifying the nutrition for the average person does have certain advantages. 

The next group of people who may want to consider going carnivore are those with a combination of diabetes and thyroid disease (of any type). 

The reason for this recommendation is simple: 

Going carnivore has the potential to put diabetes into remission quite rapidly which will have a profound positive impact on the entire body. 

If given the opportunity to remove this incredibly destructive disease from your body, you should take it. 

Again, this isn’t the only diet that can help reverse diabetes, but it’s one of the easier diets for people to grasp. 

Having said all of this, even if you were to go carnivore with a thyroid problem, I don’t see any evidence to suggest that it should be used long-term. 

The best way to use a diet such as this is to use it temporarily until you have gotten the problem you are trying to tackle under control. 

From there, I think it makes sense to transition to a whole food-based diet which includes healthy carbohydrates in the form of fruits, vegetables, and honey. 

This allows you to take advantage of the benefits of the carnivore diet without realizing the long-term potential negative outcome associated with its use. 

The Bottom Line? 

Outside of these instances (and a few select others), you won’t find my routinely recommending the carnivore diet to patients with thyroid problems. 

For the average person with thyroid disease, I don’t think the benefits outweigh the risks and potential uncertainties associated with this diet. 

Now I want to hear from you:

Were you aware that low-carb diets like the carnivore diet can have a negative impact on your thyroid and other hormones?

Have you personally tried the carnivore diet before? 

Did it work for you? Why or why not?

Do you disagree with my assessment that the risks of going carnivore don’t outweigh its benefits? Why or why not?

Leave your questions or comments below to keep the conversation going!