Keto Diet and Hypothyroidism: Is it Effective?

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When many practitioners think about a keto diet, they remember the traditional keto diet, where people ate copious amounts of fat and not much else. 

Today, many research studies and experienced clinicians have adapted keto diets to be much more balanced and healthy.  

This post will explore the variations of the keto diet, how it can affect thyroid function, health, and more. Learn if keto is something that may be right for you or your clients. 

Keto & Hypothyroidism Is It Effective | Thyroid Nutrition Eduators

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What is Ketosis?

Ketosis is when your body begins to burn fat either from food or within our own fat cells for fuel. 

Fat becomes the main source of calories, as opposed to glucose from carbohydrates and sugar.

In this fat-burning state of ketosis, the body starts to lose weight and energy levels may increase.

Origins of the Ketogenic Diet

Forms of intermittent fasting have been documented as far back as 500 BC.  The ketogenic diet mimics the effects of fasting in the body by creating a state of ketosis [R]. 

In the 1920s the ketogenic diet was a well-established treatment for epilepsy but was traded out for epileptic drugs.  As many practitioners know, the effects of these drugs on nutrient status and health can be quite devastating and have long-term consequences. 

As a result of this, the ketogenic diet has gained a resurgence in popularity for the treatment of epilepsy and now many other disorders [R].

Inspirational Case 

The Charlie Foundation was established in 1993. The organization takes its name from a young boy named Charlie who was cured of his epilepsy by following a ketogenic diet.  

Cured of epilepsy after following a keto diet for a month, the keto diet was his only intervention without additional medication.

Once his epilepsy went away, Charlie was able to eat whatever he wanted. 

As you can see, the impacts of a ketogenic diet, while restrictive, can be quite profound in a short period.  In recent years, research is gaining traction about the ketogenic diet in additional areas of health.  

Momentum in Research

In the year 2017, over 250 clinical studies were published on the topic of ketogenic diets.  

We can no longer ignore that there CAN be therapeutic benefits to this diet approach for some people. Of course, this is when the diet is tailored for their individual needs and carefully monitored by a team of skilled nutrition and health professionals.

It is important to keep in mind that eating a low carbohydrate diet is NOT for everyone.

How Does Ketogenic Differ from Ketoacidosis?


Ketosis is the state of the body making ketones. Ketones are compounds produced when the liver digests fat [R]. They become the primary fuel source in place of blood sugar. Just like glucose, ketones can be utilized by many tissues in the body [R].

If there is a long period of time between meals the body will start breaking down fat to use as a fuel source. This produces ketones. The body will think it is in a fasting state and go into ketosis [R].

Ketosis has also been seen when following a low carbohydrate diet [R]. 

The state of ketosis itself does not harm the body. In fact, it may be the reason why some neurological conditions improve quite dramatically. It can increase beneficial compounds, such as the brain-derived neurotrophic factor (BDNF). These proteins are responsible for the growth and health of neurons [R].

Ketone bodies are created on a carb-restricted diet, and they include 3-hydroxybutyrate (3HB), acetate and acetoacetate (AcAc) These are compounds produced in the liver.  Ketones serve as a fuel source for all cell types in the body [R].


Ketoacidosis refers to diabetic ketoacidosis (DKA).  It is a life-threatening condition that affects people with Type 1 diabetes and in some Type 2 diabetics [R].

It occurs when ketones are being produced at a higher rate than the body can burn. This will result in a buildup of ketones in the blood and urine. Too many ketones will lower the blood pH making it acidic [R].

Ketoacidosis is a dangerous and sometimes fatal condition that requires immediate medical attention. Symptoms of ketoacidosis include nausea, vomiting, abdominal pain, rapid breathing, and, in severe cases, unconsciousness [R, R].

Causes of Ketoacidosis

The most common cause of ketoacidosis is uncontrolled diabetes. It occurs when the body signals that insulin is too low and the following occurs [R]:

  • Blood sugar cannot get into the cells
  • The liver makes too much blood sugar
  • Fat is broken down too fast for the body to process 

Ketoacidosis can also occur during starvation that is superimposed on a body stressor such as acute illness or pregnancy [R, R, R, R, R].

What is a Ketogenic Diet?

The Ketogenic diet contains around a 4:1 ratio by weight of fat to combined protein and carbohydrates [R]. This means people consume about 20-25 grams of carbohydrate daily.  Newer versions of keto diets focus on healthy quality fats like fish, nuts, and avocados.

The intake of protein is limited to approximately 1.0 grams/kg lean body mass per day (increased for exercise to 1.25 grams/day) [R].

Translation: A traditional ketogenic diet typically consists of the following [R].

  • 10% carbohydrate
  • 20% protein
  • 70% fat. 

This is usually less than 50 grams of carbohydrate per day. With this amount of carbs, ketosis will take effect in about two and seven days [R, R, R].

Types of Keto Diets

For many individuals, adapting to a traditional ketogenic diet can be difficult to follow and can lead to poor outcomes [R].

Alternative ketogenic diets have been created in response to this.

These easy-to-follow diets can be healthy and sustainable.

They include The Modified Keto diet, The Keto-Green Diet, The Mito Food Plan, Targeted Keto, Cyclical Keto, and High Protein Keto.

Modified Keto Diets

Not just blobs of fat, the modified keto diet includes more healthy foods than the traditional keto diet.  A modified keto diet allows for up to 20% carbs, making the diet more compliant. 

Keto often also takes into account “net carbs.” 

Net carbs are the grams of carbohydrates that will affect blood sugar. The goal is to keep it regulated with lower net carb foods [R].

Fiber is another compound that regulates blood sugar. It is not digested by the body [R].

Fiber is not counted as part of the total net carb number unless there is a too low amount of fiber present.

To calculate the net carbs you would subtract the grams of fiber from the total carb number.

Total Carbs – Fiber = Net Carbs

This means any foods higher than five grams of fiber will be zero net carbs. 

Vegetables are also encouraged.  Especially non-starchy vegetables including the following:

  • Kale
  • Cauliflower
  • Broccoli
  • Asparagus
  • Onions
  • Peppers
  • Collards
  • Spinach
  • Seaweed
  • Cucumbers
  • Mushrooms

Protein is moderate on a modified keto diet and should come from quality sources such as wild salmon, sardines, grass-fed beef, seafood, and grass-fed cheeses.

Vegetarian proteins like veggie burgers are also encouraged. You want to avoid overly processed meat products containing nitrates and other artificial preservatives.

Modified keto diets should also include plenty of nuts, seeds, and judicious amounts of whole grains for extra fiber. 

For those with thyroid conditions and gluten sensitivities, you want to make sure the whole grains are gluten-free and tolerable.

The Keto-Green Diet

The Keto Green Diet was created by OB/GYN Dr. Ana Cabeca. This diet was created to help ease menopausal symptoms. The diet is outlined in her book The Hormone Fix.

The concept of the keto-green diet is to keep your urinary pH in an alkaline state. This means your urinary levels should be at 7 or above.

The diet is filled with high-alkaline foods that are designed to help balance your body’s pH levels.

A high intake of vegetables has been found to increase urine alkalinity [R].

A urine pH that is more alkaline than acidic (below 7) may reduce rates of diseases, foods that encourage alkalinity are encouraged.

Some diseases are linked to low pH level include cancer, cardiovascular disease, metabolic syndrome, and other chronic diseases [R].

The majority of the plate is filled with low carb alkaline vegetables and 20 percent of high-quality protein and fats. This is to keep an alkaline pH.

The following foods are incorporated into the keto-green diet:

  • Alkaline vegetables (kale and other greens, broccoli, sprouts, cauliflower cabbage)
  • Grass-fed meats
  • Wild-caught fish
  • Avocado, nuts, seeds and, cold or expeller pressed olive oil
  • Low sugar fruit (lemon, blueberries, strawberries, watermelon, blackberries, lime, cantaloupe, acai berries)
  • Wheatgrass
  • Spirulina

Attaining ketosis in the keto-green diet is done through intermittent fasting and no snacking. It focuses on principles that are supposed to manage the hormones insulin, cortisol, and oxytocin.

Foods like broccoli, cauliflower, sprouts, and cabbage are added to the diet to help to naturally detoxify due to their antioxidant properties [R, R, R, R, R].

Knowing your urinary pH level is a must on this diet so you will need to test your urine frequently to make sure you are in range.

The Mito Food Plan

The Mito Food Plan is taken from the term Mito which is an abbreviation for mitochondria.

Mitochondria are bean-shaped structures found in every cell of your body. They are responsible for making energy by using oxygen and nutrients as fuel [R].

When studied, mitochondria have been found to operate more efficiently when consuming fat as a fuel source when compared with carbohydrates [R].

Mitochondria are prone to disease if not properly nourished. This is of concern in areas of the body that are highly concentrated in these structures such as the heart, brain, muscles, and nerves [R].

So the idea behind the Mito Food Plan is that by incorporating these foods, mitochondria will perform better and prevent disease in those cells which have a high abundance of these structures.

Mito is almost identical to the keto green diet, incorporating a lot of non-starchy plants, seasonal fruits, and seeds like chia and flaxseed. 

It also discourages highly refined oils such as corn oil, soybean oils, and other inflammatory oils as found in fried foods. 

Developed by the Institute for Functional Medicine it is often used in challenging conditions like Parkinson’s disease and other neurological conditions. 

This low carb diet has more flexibility and its aim is more related to health instead of a ketone number.  It allows for more seasonal fruits, such as berries and regional foods. 

Targeted Keto Diet

The targeted keto diet simply is the same as the keto diet, with one exception.  Carbs are eaten before and after exercise to help support athletic performance. 

On the ketogenic diet, the body burns more fat as fuel, allowing the body to spare some of its glycogen stores [R].

Glycogen is broken into glucose and used to power muscles during exercise [R].

Carbohydrates are a better fuel source for muscles. A high-fat diet has been found to limit energy production in the muscles for athletes competing in endurance events lasting up to three hours [R].

However, if all the glycogen is depleted the workout may suffer. That is why this diet recommends eating carbs before exercise.

People should wait to do a targeted keto diet until their body is keto-adapted, typically several weeks into a ketogenic diet. 

Cyclical Keto Diet

A cyclical keto diet is a variation of the regular keto diet. It is exactly what its name implies. You would rotate between a high-fat, low carb ketogenic meal plan and a higher carbohydrate meal plan.

It allows for an intake of a higher number of carbs for 2 consecutive days during the week. The other 5 days you would consume a low carbohydrate [R].

No research is available to support this type of meal plan, but many people find this plan more sustainable than taking on a full keto diet every day of the week. 

On this plan, healthy carbs are encouraged over processed carbs.  They include the following:

  • Sweet potatoes
  • Beans
  • Lentils
  • Brown rice
  • Oats
  • Squash
  • Other root vegetables

High Protein Keto Diet

A high protein keto diet simply allows a higher percentage of calories to come from protein [R]. 

This diet is typically recommended for someone who wants to increase muscle stores [R, R]. The elderly population may also be a candidate for this diet [R]. The typical ratio is as follows:

  • 60-65% Fat
  • 30% Protein
  • 5-10% Carbs

Depending on the type of vegetables you are consuming this diet might be lacking in nutrients and fiber. Be sure to add a lot of non-starchy vegetables for a more nutritious and higher fiber diet. 

There is the theory that adding too much protein may result in falling out of ketosis due to gluconeogenesis. This is when the body creates glucose from sources other than carbohydrates such as protein [R].

Research on this topic is mixed.  Few studies have found that protein intake increases gluconeogenesis enough to stop ketogenesis. On the contrary, the amount of glucose produced had little to do with protein content in one study [R].

Diabetics have a slow release of glucose after eating protein foods over an eight hour period in research [R].  

No research has been conducted on this specific diet plan, but many people claim they feel stronger and better eating more protein. 

How Does it Compare to Intermittent Fasting?

Intermittent fasting  (IF) is an eating pattern that cycles between periods of eating and fasting. This results in a shortened amount of time that a person eats throughout the day [R].

During periods of fasting the body is forced to use its own fat stores instead of calories from the diet as an energy source. The fat will break down and create ketones, putting the body in a state of ketosis [R].

Similarly, the reliance on fat in the ketogenic diet will result in a fasting state with ketone production and reduced glucose levels. The brain will begin to rely on ketones for energy [R].

The benefits of the two diets are similar. Both have shown to help with weight loss and have anti-inflammatory effects [R, R, R, R R, R, R].

Improvements in brain function and blood sugar regulation have been seen among intermittent fasting and ketogenic diets [R, R, R, R, R, R].

Unlike a ketogenic diet, IF has no limitation on carbohydrates or protein consumption [R].

Doing a combination of intermittent fasting and keto has been shown to amplify weight loss efforts and speed up ketosis [R, R]. 

Thyroid Basics

Ketogenic diets may affect how thyroid hormones function.

If the body senses low thyroid hormone levels, the hypothalamus will release Thyrotropin Releasing Hormone (TRH) to trigger the delivery of Thyroid Stimulating Hormone (TSH) from the pituitary gland [R].

TSH binds to the thyroid gland and tells the body to release the thyroxine (T4). This inactive hormone is a precursor to the other thyroid hormone triiodothyronine (T3) [R].

TSH controls how much T4 is sent out. In the thyroid, some of the T4 is converted to T3 by the loss of one iodine molecule. The rest of the T4 is converted to T3 in the liver and kidneys [R].

When T4 levels reach maximum capacity the release of TRH is restricted. T4 levels will decrease until the brain recognizes a negative feedback loop [R].

Too low a level of T4 and the cycle will again start over [R].

T4 and T3 Regulate Metabolism

T4 and T3 help to regulate the metabolic rate of cells. Thyroid hormones also activate heat in the body. This thermogenesis affects temperature regulation which will also have a bearing on metabolism [R].

The body adapts to starvation and calorie restriction by slowing down the metabolic rate. This survival mechanism prevents body wasting and preserves energy [R].

Changes in thyroid hormone levels have been seen across various diets.

T3 & Reverse T3 Levels On Keto

Triiodothyronine (T3) is a thyroid hormone produced when thyroid-stimulating hormone (TSH) is secreted by the pituitary gland. T3 is responsible for carrying oxygen and energy to cells [R].

Reverse Triiodothyronine (rT3) is the inactive form of T3. This means it cannot perform the metabolic activities of T3 [R].

T3 and rT3 are the byproducts of the hormone thyroxine (T4). They are formed when an iodine molecule is removed [R]:

  • T3 is formed by the removal of an iodine molecule from the outer ring of T4
  • rT3 is formed by the removal of an iodine molecule on the inner ring of T4

Carbohydrate intake affects T3 and rT3 levels. A drop in T3 has been seen among low carbohydrate diets regardless of whether or not calories are restricted [R, R, R].

Reverse T3 levels increase in starvation and calorie-restricted diets despite what macronutrients are consumed [R, R]. Elevated rT3 and may be the result of inadequate calories on the keto diet.

Research Against the Keto Diet

There were only two studies showing negative thyroid outcomes in a ketogenic diet.

Both focused on children and possible pre-existing thyroid conditions.

Epileptic children were found to develop subclinical hypothyroidism after being treated with the keto diet over a 12 month period [R].

In this study, 20 (16.7%) of the 120 patients had subclinical hypothyroidism (increased TSH levels with no symptoms and a normal T4) [R].

Elevated TSH values and being female were seen as risk factors [R].

Typically, hypothyroidism occurs in 1 in 1,250 children [R]. In this study 1 in 6 of the children became hypothyroid and required thyroid replacement surgery. 

This illustrates the need for children undergoing a keto diet for epilepsy to be closely monitored for any possible thyroid dysfunction [R].

Thyroid hormone abnormalities are often common in epileptics [R, R]. Obviously, there is a connection between epilepsy and thyroid dysfunction regardless of diet. 

Epilepsy Drugs Affect Thyroid Too

Antiepileptic drugs cause shifts in TSH and T4 after just one month of use [R]:

  • Valproate
    • Decrease in T4 at 1, 6, and 12 months
    • Increase in TSH at 1, 6, and 12 months
  • Carbamazepine
    • Decreased T4 at 1, 6, and 12 months
    • Increased TSH at 1 and 6 months
  • Phenobarbital
    • Decreased T4 at 1 and 6 months
    • Increased TSH at 6 and 12 months
  • Oxcarbazepine
    • Decreased T4 at 1 month
  • Levetiracetam
    • No significant change in T4 and TSH over the entire 12 month period

Subclinical hypothyroidism was found after 12 months among users of valproate (28%), oxcarbazepine (21.4%), phenobarbital (18.2%), carbamazepine (13.9%) and zero percent within the levetiracetam group [R].

Possible Benefits of Keto in Thyroid Function

In another study, 28 epileptic children aged 6-10 years old had no significant change in thyroid function when put on a ketogenic diet for 1.9 years. Patients were asymptomatic for hypothyroidism. 

Younger epileptic children consuming a ketogenic diet had elevated cholesterol and triglycerides along with shifts in T4 and TSH. This indicates children with these risk factors should be monitored on a keto diet [R].

This research has little to do with how keto affects adults, however, those with epileptic conditions and on medications should be monitored for any pre-existing thyroid conditions before starting keto.

Other Research For The Keto Diet

Keto diet and hypothyroidism in men: A study of four healthy non-obese men experienced short-term changes in T3 and rT3 [R]. 

The men were given a 1500 calorie diet consisting of the following macronutrients:

  • 100 percent fat
  • Half fat/half protein
  • Half fat/half carbohydrate
  • Mixed controlled diet

Notable changes occurred within the full-fat diet and partial carbohydrates diet [R].

The full-fat diet resulted in hormone changes similar to those in total starvation with a 50 percent reduction in T3 and 123 percent an increase of rT3 [R].

Adding 750 calories of carbohydrates resulted in a similar trend: serum T3 decreased 24 percent and T3 rose 34 percent [R]. 

Thyroid hormone metabolism may be dependent on the nutrients in the diet as illustrated by the change in hormone function. The addition of carbohydrates may affect hormone function but 750 calories carbohydrates alone will not restore thyroid hormone levels of T3 and rT3 after total starvation [R].

This may infer that an all fat diet could affect the thyroid. But there is additional research that may indicate otherwise.

T3 and rT3 among obese individuals during total starvation were compared with an 800 calorie diet consisting of various carbohydrate levels over a period of 7 to 18 days.  

Results were similar to the first study showing the same pattern for T3 and rT3 levels for fasting:

  • T3 had decreased by 53%
  • rT3 had increased by 58%

On a carb-free diet, T3 declined 47 percent, but rT3 had no significant change [R]. 

Diets with 50 grams of CHO had no significant changes in either hormone level [R].  

This illustrates that T3 levels are affected by carbs alone no matter how many calories are consumed [R]. 

It also suggests that starvation plays a role in rT3 changes [R]

Thyroid and Very Low-Calorie Diets

Similar patterns in T3 and rT3 were seen among obese women given a very low-calorie diet (VLCD) (1,000 calories) for 28 days.

T4 was not affected, but T3 and rT3 changed in women given a high and low-carb diet.

Those on a low carb diet had larger drops in T3 (34.6%) compared with high-carb diets (17.9%). Reverse T3 increased on both a high and low-carb diet.

The changes were short-lived and returned to baseline after one week of the VLCD. 

The metabolic rate was also measured. Resting metabolic rate (RMR) dropped for both high (20.8%) and low (12.4%) carb groups. When compared with baseline they were not really significant until week three of the VLCD. 

The results of this study show that calorie intake is more of a factor for changing the metabolic rate [R]. 

T3 levels improve with the addition of carbs even on a very low-calorie diet.  

This would infer that adding some carbs to an all fat diet can improve thyroid function. However, the opposite was seen in the half-fat diet with the T3 drops.

So perhaps you need more than a minimum of carbs. Or is it the fat that is leading to a shift in T3?

You would assume that an all-fat diet may affect thyroid function based on the fact that the addition of carbs on a low-calorie diet improved T3 levels.

It is not that simple though. Since these studies have different subjects it’s like comparing apples and oranges.

Looking at additional research is vital to know what is happening to the thyroid. 

Change in T3 Metabolism During Weight Loss?

Study 1

Thyroid results were studied in 14 overweight/obese men. Eight of them were fed a ketogenic diet for six weeks. The other six were fed a low-fat diet for the same six weeks. 

The first eight men were given the low-fat diet and the six men consumed a ketogenic diet. The diets were then swapped after the first six weeks. 

Thyroid tests showed significantly lower free T3 concentrations in all of the subjects after being on the ketogenic diet when compared to the low-fat diet (3.5 vs. 4.2 pmol/L). This was found in 13 out of the 14 men in the study [R].

A group of 28 diabetics was given a low-carbohydrate, ketogenic diet (LCKD) for four months. During that period their TSH values did not change significantly [R].

Difficulty losing weight is often a symptom of hypothyroidism. 

A six-week study showed a significant decrease in body fat during a reduced-calorie and very low carbohydrate diet (8%) in eight of the 12 healthy men among over a six week period.

Fat mass significantly decreased while lean body mass significantly increased.

Total T4 and free T4 increased by approximately 13 percent by week 6.

About 70 percent of the variations of fat loss was due to serum insulin levels.

There was no change in T3 uptake or other hormones concluding carbohydrate restriction does not affect thyroid function [R].

Another study of 9 lean men on a mixed-calorie ketogenic for 4 weeks measured hormone function and metabolic rate.

Though there was a significant decrease in T3, which was not related to the metabolic rate. Symptoms of hypothyroidism were also not seen [R].

This illustrates there may be another reason for the decrease in T3 among low carb and keto diets. 

Study 2

Another study evaluated the relationship between thyroid hormone levels and metabolic rates of varying carbohydrate diets in six healthy males.

Thyroid hormone levels, resisting energy expenditure, and urinary nitrogen was measured for 11 days [R]. 

The protein content was the same for all three groups with calories set to maintain weight. With each diet having varying levels of carbs: 

  • Very low (2% carb, 15% protein, 83% fat)
  • Medium (44% carb, 15% protein, 41% fat)
  • High (85%, 15% protein, 15% fat) 

The very low carb diet resulted in decreased T3 with an increase of T3 uptake, free T4, and rT3.

TSH did not change among any diet [R]. 

The increase in rT3 could be due to the body thinking it is in starvation mode [R]. 

Starvation can lead to hypothyroidism and is often characterized by the following [R]:

  • Elevated TSH
  • Decreased plasma T3
  • Decreased resting energy expenditure or metabolism
  • Decreased nitrogen excretion

On a very low carb diet, nitrogen excretion was increased but the metabolic rate did not change.

Low carb diets lead to protein wasting but protein wasting occurs independently of decreased plasma T3 levels [R].

Changes in T3 and rT3 do not automatically mean hypothyroidism.

Thyroid conditions are accompanied by changes in metabolic rate, T4, TSH mIU/L and the presence of antibodies [R]. 

Without the presence of changes in TSH and resting energy expenditure (which would change in hypothyroidism), it was concluded that carbohydrate restriction has different results from that of starvation [R].

Keto for TSH and T4

The lack of research showing changes in TSH and T4 proves little connection between keto and hypothyroidism.

However, it is recommended to monitor thyroid hormone function and symptoms while on a keto diet.

Why Ketogenic Diets Change Thyroid Hormones

One theory is that consuming fats is more metabolically efficient.

A gram of fat gives you 9 calories of energy compared with 4 calories in 1 gram of protein and carbs.

With over twice the calories in fat, it may take a lesser amount of T3 to utilize the energy than from carbs and protein [R].

Lower T3 levels may also help the body retain its protein stores [R].

Thyroid Sensitivity

It has been proposed that perhaps under the keto diet our body adapts to function normally with lower T3 hormone levels. The body becomes sensitive to T3 so you will need less of it for proper thyroid function [R].

This means that normal reference ranges of T3 should not apply to people on a ketogenic diet since they are consuming fewer carbs than the average person [R].

How Keto Affects the Thyroid Long Term

The keto diet has been shown to benefit those with thyroid issues, but there is limited research on its long-term effects.

Thyroid function should be evaluated by monitoring all of the thyroid hormones when on a keto diet. 

Just like anything, the keto diet and hypothyroidism should have ongoing monitoring.

Possible Strain On Adrenal Glands

The adrenal glands are two small structures that sit on top of each kidney. They produce hormones that regulate many body processes including metabolism.

The adrenal glands are responsible for producing the hormones cortisol and aldosterone. Cortisol is produced as a reaction to stress. Aldosterone regulates sodium and potassium balance in the body.

A downside of ketosis is that it may put a major strain on the adrenal glands, especially if not followed with the highest quality foods and supplements [R].
This constant strain may result in mild to severe adrenal insufficiency. Symptoms of adrenal problems include [R]:
  • Fatigue
  • Sleep issues
  • Sugar cravings
  • Salt cravings
  • Unexplained weight loss
  • Lack of motivation
  • Brain fog
  • Weakness
  • Light-headedness
  • Loss of appetite
  • Low blood pressure
  • Loss of body hair
  • Joint pain
  • Low blood sugar
  • Irregular or missed menstrual periods
  • Low libido
Those with thyroid, autoimmune, and adrenal conditions may want to monitor their adrenal function when doing keto.

Increase In Cortisol Production

When our bodies are in a stressed state we have an evolutionary response to fight or run away.
That fight or flight feeling comes from cortisol, the hormone released by the adrenal glands.
Like thyroid hormones, cortisol secretion is controlled by the hypothalamus, the pituitary gland, and the adrenal gland also known as the HPA axis [R].
Cortisol regulates a number of metabolic processes: blood pressure, blood sugar, memory function, reducing inflammation, and fetal development [R].
The levels of cortisol need to be balanced. Having too high or too low of a level can be problematic [R].

Low levels of cortisol can affect the libido and menstrual cycle.

High cortisol levels may have a connection with anxiety and depression.

The anti-inflammatory effects of cortisol are diminished when someone undergoes physiological stress on a daily basis. Immune cells will become numb to cortisol production. This can lead to a cascade of inflammation and disease [R].
A low-carb diet can lead to a decrease in thyroid hormone levels and can increase cortisol production putting further strain on the adrenal glands [R, R].
Evaluating stress levels before and during keto diet is important. If you find you are a highly stressed person be sure to incorporate stress relief techniques like meditation, exercise, and gratitude practices to prevent cortisol surges.
Monitoring the adrenal function is recommended on a keto diet.

Keto Diet Benefits and Risks

Aside from hormonal changes, there are both benefits and risks to be aware of when doing the keto diet.

Benefits of a Ketogenic Diet

Benefits of the ketogenic diet include improved health conditions, weight loss, and brain health.

Keto Supports Weight & Body Fat Losses

Being in a state of ketosis supports weight loss, reduced body fat, and may also improve blood sugar regulation [R, R]. 

Leptin, the hormone responsible for regulating appetite, has been increased when on a keto diet [R].

Keto Benefits Brain Health

A keto diet benefits brain health.

A clinical study showed improved memory in healthy older adults [R].

Keto Benefits Inflammatory Conditions

Keto diet has been shown to reduce inflammation and improve insulin sensitivity [R].

Blood pressure, diabetes, and triglycerides have been regulated on a keto diet [R].

Keto May Benefit Cancer Patients

A keto diet may even benefit those undergoing cancer treatment [R].

Keto may inhibit cancer by the following mechanisms:

  • Anti-angiogenic
  • Anti-inflammatory
  • Proapoptotic or cell death

Other people are using the keto diet for disorders like Alzheimer’s, dementia, neurological conditions, mood disorders, and more.  Research is starting to support the use of keto for some of these conditions [R].

Low Gluten On A Keto Diet Is Optimal for Thyroid

Keto diet and hypothyroidism effects should also consider gluten intake and other sensitivities. When it comes to the thyroid, eliminating gluten is beneficial.

Gluten on a keto diet, while not implied to be restricted, is by nature very low in gluten.

Our take?  Eliminating gluten can be alone very supportive of thyroid health.

Risks of a Ketogenic Diet

While no direct risks of a keto diet and hypothyroidism exist, keto diet comes with a few general risks that you should be aware of.

Keto Flu

Some will experience flu-like symptoms about two to seven days after starting the keto diet. This condition is known as the keto-flu and can have the following symptoms:

  • Headache
  • Brain fog
  • Fatigue
  • Irritability
  • Nausea
  • Difficulty sleeping
  • Constipation

The condition is short term and is not recognized by the medical community. 

Risks of the keto flu are reported to be reduced if people consume enough sodium and, stay hydrated, and get adequate rest. 

Ketosis can be a shock to a body used to consuming larger amounts of carbs. Keto flu has been compared with symptoms of caffeine withdrawal [R].

Those with a very low carbohydrate intake are prone to getting the keto flu. Adequate carbohydrate intake is recommended for the prevention of this condition. [R].

Filtered water and electrolytes can also help reduce symptoms. Bone broth is a great drink to have when the flu hits. Kettle & Fire is a great substitute if you do not have time to make it from scratch.

Strenuous exercise should be avoided during this time. Lower impact activities like walking and yoga are recommended. 

Beyond the short-term keto flu that some people feel, there are risks for some categories of people. 

Risks in Those with Diabetes

Although research shows the benefits of a low carb diet, there are still some risks for diabetics [R].

Hypoglycemia can occur in those with diabetes who do not closely monitor insulin and oral diabetes medications [R].

Risks in Women Who Are Lactating 

In a case study of a lactating woman following a ketogenic diet, one woman went into ketoacidosis. 

Lactation creates a high energy demand, so a keto diet may not be well-suited during breastfeeding [R].

Risk of Dehydration

Electrolyte imbalances and dehydration can occur when someone isn’t following the keto diet correctly [R].

Consider Liver Health Before Starting a Keto Diet

The liver plays an important role in thyroid hormone metabolism. There is a symbiotic relationship between the thyroid and the liver. The thyroid depends on the liver to metabolize hormones.

Adequate levels of hormones are also needed for the liver to function properly.  

Thyroid diseases often are associated with abnormal enzyme levels in liver function tests [R]:

  • Liver disease: High thyroxine-binding globulin and thyroxine levels
  • Hyperthyroidism: High alanine aminotransferase (ALT) and alkaline phosphatase (ALP) levels
  • Hypothyroidism: High levels of aspartate aminotransferase (AST)

That is why thyroid conditions often are the result of a congested liver. Abnormalities and toxin buildup prevent T4 from properly converting into T3 [R].

T3 is responsible for energy production so this can mean big problems for our metabolism as well as other body systems (heart, nervous system, bone, skin, and hair) [R].

Good liver function is essential for a healthy thyroid. Liver health is something to consider on a ketogenic diet for the following reasons:

Ketone Bodies Strain the Liver

The liver has an abundance of mitochondria.

These organelles are responsible for metabolism and the production of ketone bodies.

Using ketones as a main fuel source will put further strain on the already taxed organ [R].

Toxins from Certain Foods Strain the Liver

Toxins come from animals fed corn, grain, and other inflammatory foods. Animals fed these foods will have toxins stored in fat tissue [R]. 

The keto diet can be higher in animal meats than some diets, but it is still only moderate in protein. 

Animal products take longer to digest and can be filled with toxins if choosing low quality. The liver will then have to work harder to detoxify the body [R, R].

For these reasons, we recommend eating organic and grass-fed meats and cheeses whenever possible.

Thyroid patients should consider testing the liver before starting the ketogenic diet.

Side effects

Some patients can also experience side effects while on the keto diet.

Acidic pH, Inflammation and Weight Gain

Being on the keto diet for too long can decrease the body’s pH making it too acidic, especially if not eating a modified keto plan. 

A keto diet that is high in certain foods may cause an acidic environment in the body. A diet high in meat has been found to be more acidic to the body. Alternatively, more vegetables in the diet resulted in more alkaline urine [R].

A prolonged acidic state of the body leads to chronic inflammation and results in fat stores and weight gain [R, R].

Women are more at risk for an immune reaction. Any women with an existing autoimmune disorder or thyroid condition should monitor how they feel on the keto diet [R].

Consuming more vegetables, fruits, meat, chicken, and healthy fats with less sugar, processed foods, and sweetened beverages will maintain a lower pH to keep the body balanced.

Carnitine deficiency

Carnitine deficiency has been seen with a ketogenic diet.

This may be linked to early research where patients with epilepsy actually have carnitine deficiency at baseline.

Carnitine is known to be supportive of epilepsy treatments with or without a keto diet [R].

Keto Can Be Hard to Follow

A restrictive diet can be hard to follow.  As clinicians, however, we have seen a variety of outcomes on this diet.

Some people have followed it for years and become very healthy, while others fall off the diet very quickly. 

It probably is more suitable for some genetic profiles. 


Contraindications are found among some conditions. In a recent review of the ketogenic diet, the following conditions are those that should avoid a ketogenic diet [R]:

  • Pancreatitis
  • Fulminant liver failure 
  • Disorders of fat metabolism 
  • Carnitine metabolic disorders
  • Porphyrias
  • Pyruvate kinase deficiency 

What Do The Experts Say?

Izabella Wentz, The Thyroid Pharmacist  

Izabella Wentz, better known as the Thyroid Pharmacist, is a pharmacologist who specializes in Hashimoto’s disease. She has done research on how to improve her own case of Hashimoto’s after years of no relief through medication alone.

She uses functional nutrition to get to the root cause of autoimmune thyroid diseases.

Izabella is an advocate for aversion from inflammatory foods. These include gluten (due to the sensitivity of up to 88% of people with Hashimoto’s), soy, canola, and rapeseed oils. These foods have potential goitrogenic properties that have been found to worsen the thyroid health and be problematic for those with Hashimoto’s.

Izabella Wentz’s recommendation is to understand that everyone is unique. Macronutrient needs and ratios will vary from person to person and might need to be adjusted accordingly.

Amy Myers, MD  

Amy Myers is a preventive medicine physician who has been practicing for over 15 years. One concern that Meyers has is how chronic stress can play a role in the health of you your adrenal glands. 

The goal of a keto diet is to achieve the metabolic state known as “ketosis” by reducing carb intake. This leads to a decrease in thyroid hormone levels and an increase in cortisol putting a strain on the adrenals. 

If the adrenals are already fatigued, ketosis will stress them even further. Those who are not under adrenal stress will do fine on the keto diet. 

She recommends the Autoimmune protocol diet (AIP).  Much of what is consumed on a typical keto diet is already AIP. Meyers’ advice is to listen to the body to understand what it can and cannot tolerate.

Dr. Anna Cabeca, D.O.  

Dr. Anna Cabeca specializes in bio-identical hormone replacement therapy, menopause, and age management medicine.  

Dr. Cabeca is an expert in alkalinity and pH balance in our bodies. She is the creator of the Keto-Green diet and recommends it for its ability to help with weight loss, aging, and hormone balance.

Cabeca feels that weight loss is one of the biggest benefits of this diet.  Keto suppresses your appetite, partly by stabilizing the appetite-modulating hormones like ghrelin and leptin. 

Aging is another benefit. It can help steady insulin levels, improve your lipid profile which is a powerful anti-aging system. She has found the keto diet to alleviate symptoms of polycystic ovarian syndrome (PCOS), acne, neurological issues, cancer, diabetes, depression, and menopause. Increased energy has also been a positive outcome of her keto diet.

Dr. Cabeca has found no research to support keto diets in any way trigger or exacerbate hypothyroidism or any thyroid conditions.  

She feels the side effects of the keto flu can be easily remedied with hydration and incorporation of nutritious foods. 

Dr. Cabeca does have concerns about nutrient deficiencies in selenium and vitamin D. This can be remedied by eating plenty of fiber-rich plant-based foods. 

Dr. Cabeca admits most patients do struggle at the beginning of starting. It might take a few weeks to see results, but patients who stick with it often feel better after going through the program. 

Dr. Stephen Phinney & Dr. Jeff Volek of Virtua Health

Dr. Stephen Phinney and Dr. Jeff Volek, are experts on the science of carbohydrate restriction and metabolic health. They are part of the team at Virtua Health, an organization dedicated to researching reversing type 2 diabetes.  

Dr. Phinney was involved in the various studies measuring thyroid hormone function on very-low-calorie ketogenic diets. These are their thoughts on the topic:

  • If the thyroid or liver could not make enough thyroid hormone, TSH would be elevated.
  • There is limited research on TSH measures
  • If the liver failed to make adequate T3, then TSH and T4 should become elevated

In all of their research on keto, the following was discovered:

  • T4 decreased slightly
  • T3 dropped dramatically
  • There were no clinical symptoms indicating overt hyperthyroidism
  • Resting metabolic rate was unchanged
  • A disconnect between T3 and resting energy expenditure

The interpretation of the research is that ketogenic diets increase tissue sensitivity to T3 resulting in a decline of serum levels with no change in metabolic reactions. 

In this theory, the thyroid and liver will do less work to carry out their metabolic processes. 

Eating more carbohydrates may lead the thyroid and liver to produce more thyroid hormone. It is similar to forcing the pancreas of a type 2 diabetic to make more insulin.

Thyroid hormones change with a low-carbohydrate, high-fat (LCHF) diet. Volek and Phinney feel that people should be compelled to eat more carbs to maintain normal thyroid function.

Danielle Carbone Aberman, RDN

Danielle is a Registered Dietitian and certified health and wellness coach. She focuses on migraine relief. She is a keto expert and found that the ketogenic diet can benefit migraine sufferers. She has a three-point plan for alleviating migraines with keto.

Nutrition Supplements on Keto Diets

Supplements that may be helpful when following a ketogenic diet include the following [R, R]:

  • L-carnitine 
  • Alpha-lipoic acid 
  • Coenzyme Q10 
  • Cod liver oil
  • Magnesium 
  • Potassium
  • Vitamin C 
  • Vitamin E 
  • Vitamin D3
  • Iron
  • Calcium
  • Multivitamin consisting of all essential B-vitamins and minerals.

Kelly’s Personal Experience with Keto

I was diagnosed with hypothyroidism in 2016 and was determined to find out why my body was reacting this way.

Through my own research, I discovered that testing for food allergies and sensitivities might be the answer. 

Food Sensitivity Testing

The Lifestyle Eating and Performance (LEAP) food sensitivity test showed I had aversions to wheat, corn, rice, soy, and dairy.

After months of trying different diets, I still was experiencing hypothyroid symptoms. I was constantly too hot or too cold. I had anxiety attacks and brain fog.

How Keto Changed Kelly’s Life

I went to several doctors but it was not until I found a registered dietitian who suggested I try the keto diet that things started to change.

After implementing this diet I quickly noticed a difference!  I was sleeping better, my brain fog was gone and I had less hot flashes. I also lost about 12 pounds over the course of a year.  

Keto Side Effects

When I first started keto, I was always thirsty. I had to replenish my electrolytes twice a day. I was able to achieve a state of ketosis but my carb intake was too low and it was causing side effects.

I decided to increase my carb intake from 20 to 30 grams up to 40 and 50 grams. This really helped me feel better while adjusting to the diet.

Finding What Worked

In the beginning, I kept track of my macros. However, after a while, I stopped recording my intake. This as because I realized what I needed to eat to maintain the right balance and feel good.

Being on the keto diet has been beneficial for me. It improved my energy levels, stopped my afternoon hunger crashes, and sugar cravings. 

Now I eat three meals every day and have a small treat after dinner.

I have learned to cook keto-friendly foods fat bombs and fathead pizza: a staple in the keto diet.

This pizza is made with low carb, gluten-free dough, cheese, and egg.  Fat bombs are made of MCT oil and melted chocolate.

The Benefits of Keto

A surprising benefit to being on keto is having a leaner, toned, body. I had the energy to work out five times a week. I incorporated weights, kickboxing, and running. After implementing this exercise regimen I saw a huge difference in my body. I really believe that keto can be life-changing for people with health issues. 

I did keto for over a year and a half religiously. I don’t recommend restricting carbohydrates from your body for that long.  It’s not sustainable. I got to the point where my weight was good,  my head was clearer, but I was not happy. 

The Downside of Keto

During the keto diet, I felt like I was missing out on some fun foods at parties, holidays, and nice dinners. Alcohol was also a huge issue. My tolerance for alcohol decreased and I could not have more than two drinks.  If I had a third drink I would get wasted and could guarantee a nasty hangover the next day.   

Due to my food sensitivities, I do not eat any bread, pasta, or processed foods. With those limitations, it may seem like I am doing keto. However, I have added 4 to 5 servings of fruit and vegetables per day. I will also have meat on most days. 

Our Recommendations for Keto & Thyroid Conditions

Every single body is different. What works for one may not work for all. That is why nutrition needs to be individualized.

The benefits of the keto diet are highly dependent on the quality of the foods eaten. 

As the other experts recommend, it is important to listen to your body. Listen hard enough and it will tell what it needs. 

There are many ways to incorporate healthy eating. We recommend talking to a nutrition professional before starting the keto diet, get your blood work taken twice a year, and follow up with your doctor and a nutrition professional on any concern or questions you may have.

It is very important to improve the quality of your diet first before embarking on a restrictive diet plan. 

If you are a nutrition professional you want to address what is happening with your client and how they are feeling as they embark on different nutrition protocols. Play around with the diet and macro ranges until they are feeling the best.

When in doubt, address the gut

Supportive Keto Resources and Products

Keto should be done under the supervision of a nutrition professional like a Registered Dietitian.

As a practitioner,  you want to provide your clients with the best resources.

That is why we are recommending the meal planning course from a Keto Expert, Registered Dietitian Laura Clevenger.

Keto Queen Meal Prep Course Keto Diet and Hypothyroidism | Thyroid Nutrition Educators

Her Keto Queens Meal Prep Course will teach the following:

  • How meal prepping can set you up for success
  • How to embrace whole nourishing foods to fuel your body
  • Learn how your body can thrive in a fat-burning state.

If you are just looking to learn more about the Keto lifestyle and want some yummy recipes. Check out The Keto Queens cookbooks here.

As we mentioned before, bone broth is a great food to incorporate to prevent dehydration on the keto diet. Some of our favorite brands include Kettle & Fire, which comes in either chicken or beef bone broths. Get FREE shipping when you purchase 6 boxes or get up to 33% off when you subscribe.

Learn more here and use Rakuten to get up to 2.5 percent cashback on what you purchase.

We also have many recipes on our site to help you transition from keto to AIP

Are you looking for keto snacks on the go?

Companies like The Keto Box have keto subscription services that will send them right to your door. Be sure your snacks are low in sugar and net carbs.

Thrive Market is another subscription service offering keto foods. Get a $20 shopping credit when you sign up for just one-month membership.

Stay hydrated with electrolytes.

Measure ketone bodies with a ketone monitor, blood, and urine strips.

Measure urinary pH with these test strips.


This diet is not intended for everyone. Some feel great on a low-carb, high-fat diet and will show optimal lab values.

Others may not do as well. Low-carb intake has been found to worsen thyroid conditions in some individuals. That is why thyroid levels should be monitored while on any type of keto diet.

Getting enough nutrient-dense carbohydrates is also important. A ketogenic diet should consist of lots of fresh, non-starchy vegetables, seeds, nuts, healthy fats, and wild and organic grass-fed meats. These foods can have therapeutic value for people who struggle with autoimmune disorders.  Nutrients in these foods will help the thyroid to function properly.

Close attention should be paid to nutrition adequacy. This can be done by working with a team of trained health professionals including an endocrinologist and a Registered Dietitian with special training in ketogenic diets. 

More Thyroid Nutrition Articles

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12 thoughts on “Keto Diet and Hypothyroidism: Is it Effective?”

  1. A ketogenic diet is often used to reverse fatty liver in humans before bariatric surgery; apart from people with carnitine deficiency, who can’t clear the fats into ketones in the first place, I don’t think this is a real risk; the reference you give says ketones don’t accumulate in the liver. Animal ketogenic diets, as this paper points out, are not good translational models, because a rodent’s small brain means it only needs a sliver of its energy preserved as glucose or ketones compared with a human, so ketosis needs to be forced with very low protein levels and restriction of choline, explaining fatty liver in such animals.

    An additional factor in the thyroid question is that T3 and T4 can go through enterohepatic recycling if there is enough fat in the diet, potentially elevating the blood level if this is a medication (if not, thryroid activity will be down-regulated to compensate)

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