HomeHealth articleshypothyroidismHow Does the Keto Diet Affect Thyroid Function?

Keto Diet and Hypothyroidism - Exploring the Relationship

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A keto diet is low in carbohydrates and high in protein. Read the article to understand its relation to thyroid functioning.

Written by

Dr. Saima Yunus

Medically reviewed by

Dr. Achanta Krishna Swaroop

Published At December 4, 2023
Reviewed AtDecember 4, 2023


Thyroid hormones are essential for proper metabolism, and they are directly correlated with body mass and energy expenditure. The ketogenic diet, also known as the keto diet, has become popular in recent years for its benefits in overall health, including weight loss. The use of ketone bodies (causing 50 to 85 percent of oxidative metabolism) is evident only after three to seven days of starvation. However, people with hypothyroidism must be more cautious about adopting this low-carbohydrate, high-fat diet due to concerns about its impact on thyroid function. In the following article, the focus will be on exploring the connection between the keto diet and hypothyroidism, targeting the potential benefits and considerations for those with an underactive thyroid.

What Is Hypothyroidism?

Hypothyroidism is caused by an underactive thyroid gland, leading to reduced production of thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3). These hormones are essential in regulating metabolism, energy production, and overall bodily functions. Common symptoms of hypothyroidism include:

  • Fatigue.

  • Weight gain.

  • Sensitivity to cold.

  • Difficulty concentrating.

What Is a Ketogenic Diet?

The ketogenic diet contains low carbohydrates and high-fat content. It acts by triggering the natural metabolic process of the body called ketosis. Consumption of minimum amounts of carbohydrates leads to deprivation of the natural body fuel source, glucose. Hence, it forces the body to use stored fat as fuel instead; this breakdown of stored fat leads to the production of ketones (a type of fatty acid). These are further released into the bloodstream, where the muscles and other tissues use them as fuel. Generally, ketosis is seen during a fasting state. However, it can also take place in the absence of glucose and the presence of medium-chain triglycerides (MCTs), like the ones found in coconut. The keto diet helps reduce inflammation and regulates the immune response, especially regarding the thyroid. Carbohydrates and sugars are regarded as highly inflammatory foods. Therefore, the best diet for hypothyroidism must help to eliminate foods that promote inflammation.

How Does the Keto Diet Affect Thyroid Function?

The ketogenic diet involves a significant reduction of carbohydrate intake and replacing it with increased fat consumption. This leads to the body entering a state of ketosis, mainly using ketones for energy instead of glucose derived from carbohydrates. The research on the specific effects of the keto diet on thyroid function is limited. However, some studies suggest potential impact.

The benefits of the keto diet in hypothyroidism include:

  • Weight Loss: The keto diet is usually associated with weight loss, which is beneficial for individuals with hypothyroidism, as excess weight can worsen the symptoms and contribute to thyroid dysfunction.

  • Stabilized Blood Sugar Levels: Reducing carbohydrate intake in the keto diet may help stabilize blood sugar levels, preventing insulin spikes and promoting better metabolic control.

What Are the Nutrients Essential for Hypothyroidism?

Maintaining a well-balanced diet with essential nutrients improves overall health and may support thyroid function. However, these nutrients do not cure hypothyroidism:

  • Iodine: Iodine is a main component of thyroid hormones. However, it is important to note that excessive iodine intake can also be harmful, particularly in individuals with autoimmune thyroid conditions like Hashimoto's thyroiditis (an autoimmune disorder where antibodies produced by the body attack the thyroid gland).

  • Zinc: Zinc is important for the adequate functioning of the thyroid gland and the synthesis of thyroid hormones. Good sources of zinc include meat, dairy products, nuts, and whole grains.

  • Selenium: Selenium is a trace mineral that is essential in converting thyroid hormones (T4 to T3) and has antioxidant properties. Foods rich in selenium include Brazil nuts, fish, meat, poultry, and sunflower seeds.

  • Iron: Iron helps in the production of thyroid hormones. Iron deficiency can contribute to hypothyroidism. Iron-rich foods include red meat, poultry, fish, beans, and fortified cereals.

  • Vitamin D: Vitamin D is vital for an individual's overall health and may have a role in thyroid function. Sources of vitamin D include sunlight, fatty fish, and fortified foods.

  • Vitamin B12: Vitamin B12 produces thyroid hormones and supports the nervous system. It is present in animal products such as fish, meat, eggs, and dairy.

  • Omega-3 Fatty Acids: These essential fatty acids, found in fatty fish, flaxseeds, chia seeds, and walnuts, have anti-inflammatory properties and may benefit individuals with thyroid conditions.

Does Reducing Carbohydrates Inhibit Hormone Production?

It is believed that a prolonged state of calorie restriction or fasting decreases the production of the T3 hormone. This helped to slow down metabolism, aggravating the rates of survival during times of food shortage. However, lower T3 and slower metabolism are usually undesirable when food is abundant, particularly in the case of an underactive thyroid. A ketogenic diet resembles starvation or fasting. This means it might limit T3 production and potentially influence metabolism. Certain studies have suggested that after a period of starvation, eating only carbohydrates can normalize thyroid hormone levels. The most common reason for starting a ketogenic diet (KD) is to lose weight. Randomized controlled trials have demonstrated that more body mass is lost when individuals follow a keto diet rather than a high-carbohydrate low-fat (HCLF) diet.

What Are the Specific Considerations for Individuals on Keto Diet With Hypothyroidism?

  • Nutrient Deficiencies: Strict adherence to the keto diet without careful planning can lead to nutrient deficiencies. Individuals with hypothyroidism should ensure they get sufficient vitamins and minerals, such as selenium and zinc, which are crucial for thyroid health.

  • Iodine Intake: The keto diet might reduce iodine intake inadvertently since many iodine-rich foods, such as certain fruits and vegetables, are limited. Iodine is helpful for thyroid hormone production, and improper levels can affect thyroid function.

  • Consulting a Healthcare Professional: Before starting the keto diet, individuals with hypothyroidism must consult with a healthcare provider to ensure the diet is in accordance with their specific health needs.


While the keto diet may offer certain benefits for individuals with hypothyroidism, it is essential to approach it with caution and under the guidance of healthcare professionals. Balancing the potential advantages, such as weight loss and stabilized blood sugar levels, with adequate nutrient intake and thyroid support is essential. The response of every individual to the keto diet may vary, and a personalized approach that considers individual health status is recommended for those with hypothyroidism.

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Dr. Achanta Krishna Swaroop
Dr. Achanta Krishna Swaroop



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