Fasting and Thyroid Conditions: Is it Possible?

Fasting and Thyroid

Fasting and Thyroid Conditions: Is it Possible?

There are two things I know when it comes to achieving and maintaining good health: fasting is second to none, and having a healthy thyroid function is a must! Can fasting and thyroid conditions coincide?

Fasting and thyroid conditions can be compatible, if done correctly. The thyroid is a small, but extremely important gland in the human body. The National Institute of Health (Diabetes, Digestive and Kidney Diseases division) describes the thyroid as “a 2-inch-long, butterfly-shaped gland weighing less than 1 ounce. Located in the front of the neck below the larynx, or voice box, it has two lobes, one on either side of the windpipe. The thyroid is one of the glands that make up the endocrine system. The glands of the endocrine system produce and store hormones and release them into the bloodstream. The hormones then travel through the body and direct the activity of the body’s cells.” Can we fast with thyroid conditions? Let's take a closer look. 

Thyroid conditions can have a tremendous impact on a person’s health and are on the rise: Autoimmune thyroid affects millions, and oftentimes goes undiagnosed. According to the National Cancer Institute, there were 53,990 estimated new cases of thyroid cancer in 2018, with rates for new cases rising on average 3.1% each year over the last 10 years. Death rates have been rising as well, 0.7% each year over 2006-2015.1

According to the National Institute of Diabetes and Digestive Kidney Diseases, other thyroid conditions are problematic as well: approximately 4.6 percent of the U.S. population ages 12 and over has an underactive thyroid (hypothyroidism)2, and 1 person out of 100 in the U.S. have an overactive thyroid (hyperthyroidism)3

When thyroid function is negatively impacted, it has ramifications for every system of the body. That makes thyroid conditions one of the most misdiagnosed conditions in the United States. This is where fasting comes into play. We often hear that we can't fast with a thyroid condition. However, fasting and thyroid health can work extremely well.  

The Power of Fasting and Thyroid Health

When it comes to battling many of today’s health issues, the entire premise of modern medicine is incorrect. In the past, diseases like cholera and smallpox could be treated with medicines like penicillin and other antibiotics, but times have changed. Yellow fever has been replaced by heart disease, Type II Diabetes, thyroid issues and other diseases that are more dietary in nature. In other words, instead of looking for the latest drug, the best form of treatment is to fix cellular dysfunction and incorporate ancient healing strategies such as fasting.

While modern medicine hasn’t embraced fasting as a viable health option (yet), the practice has been around since the beginning of time. Fasting is known to rejuvenate and revitalize the body. Even animals will fast when they are stressed, ill or feel unease. The refusal to eat is a form of self-preservation to remove waste products and promote healing of the body. Fasting and thyroid health go hand in hand: fasting makes us more responsive to our hormones, thus improving thyroid function. 

Today, the philosophy on eating is the polar opposite of the ancient practice of fasting: We are now in a constantly fed state. We have gone from an average of eating three meals a (day, breakfast, lunch, and dinner) to eating five to six meals a day: breakfast, a snack, lunch, snack, dinner, and another snack. This change in eating habits has had a detrimental effect on our health. 

Fasting and Thyroid Conditions: Fixing the Thyroid

I’m always asked, “Can these thyroid conditions be reversed?” Absolutely. Get rid of the cause and the body reverses them. Contrary to popular belief, the doctor doesn’t do it, the body does. When you get rid of the causes through my multi-therapeutic approach (including fasting), the body can do amazing things. 

Here’s a common scenario for many thyroid patients: you’re taking the thyroid medication that your doctor prescribes, and your blood work looks normal. However, you’re still losing your hair, your skin is still dry, and you have no energy. You’ve even gained 20 pounds. You’re doing everything the doctor suggested, but it’s not working. Why? We haven’t gotten to the exact cause of the thyroid condition.

Most doctors simply address thyroid conditions without an understanding of the cell’s ability to receive the messages needed to function properly. This is where fasting and thyroid health fit together. Fasting makes the body more responsive to the hormones we are producing. Therefore we start to feel better. 

Fasting and Thyroid Health: Check Your Hormones

There are three important hormones that are key to thyroid health: TSH, T3, and T4. These hormone levels can appear normal when checked, but they hold the key to potential thyroid conditions. All of these can be altered for the better through the art of fasting:

  1.     T4 doesn’t convert to the active hormone T3. T4 hormone must be converted to T3 active hormone. If this conversion does not take place or is shunted into another direction (as in times of stress), then the message to the cell will never get through.  ONLY active T3 can be used in the cell.
  2.     Active T3 can’t be used in the cell because its receptors on the cell are blunted. An important point that I teach is that hormone problems are not necessarily problems with hormones themselves, but rather the receptor to the hormone. This is similar to Type II Diabetes, where the diabetic has plenty of insulin but the receptors to the insulin are blunted and unable to “hear” the message in order to allow the glucose in the cell.  Therefore, the glucose cannot get into the cell to produce energy. A similar situation occurs with the thyroid and T3.
  3.     You could potentially have an autoimmune condition called Hashimoto’s.  It is estimated that 80% of thyroid conditions are an autoimmune related condition known as hashimotos. What people may not realize is that most thyroid conditions are autoimmune related. Most of these conditions also go undiagnosed, because most doctors do not run the correct blood work to check for autoimmune hypothyroid. Many are hesitant to check because the treatment is the same, whether you are hypothyroid or autoimmune hypothyroid.

All of these potential reasons for thyroid dysfunction can be helped through fasting.

Fasting and Thyroid Conditions: Decrease Inflammation

Fasting is the quickest way to decrease cellular inflammation, because it allows the body to direct all of its energy towards healing. I say this with confidence because it has changed my life and made a greater impact on improving my cellular health than any other strategy.

In one study conducted on laboratory mice, researchers note that nuclear T3 levels are maintained at relatively normal levels in the pituitary of the fasted animal and fractional T3 receptor occupancy may actually increase.4

Another study comparing the levels of thyroid levels between impaired fasting glucose and impaired glucose tolerance found that fasting subjects had higher levels of F3, while those who were glucose impaired had lower levels of F3. Researchers concluded that the difference in thyroid hormone levels may play an important role in the different pathological mechanisms of IFG and IGT.5

As a person gets accustomed to fasting, the body gets more and more efficient with every subsequent fast. Fasting on a consistent basis can help reduce or even eliminate many of the ailments in today’s society: cells become more efficient at utilizing fat, which burns cleaner than glucose. The body becomes more responsive to hormones. Brain fog dissipates, weight loss is easier, and most hormonal problems may be eliminated, and that includes thyroid conditions. 

Fasting and Thyroid Health: Will going too “low carb” affect my ability to make adequate thyroid hormone?

This is where I will introduce my concept of “Diet Variation”.

Our ancestors varied their diet based upon what was available. Insulin carries many roles in its relation to other hormones, especially regarding the hormone convergence. Hormone convergence means hormones need to be converted from one form to another for active use. One of the best examples of this conversion is thyroid hormone. Thyroid hormone T3 is the active form of the hormone that helps our body (cells) use fat for energy.  Active Free T3 has many other functions as well, such as the overall health of our skin and hair, and even daily energy. Therefore, if your cells don’t get enough of the message, you will not feel well or burn fat efficiently. T4 is the inactive form that must be converted to the active T3. If the conversion is hindered in any way, the lack of T3 will affect how you feel and use fat as energy.

Fasting and Thyroid Health: Vary the Diet!

Insulin is needed for this conversion to take place. Therefore, if insulin is low too long the lack of active T3 can become a problem. Those on a low carb diet for long periods can develop very low insulin. This impacts not only fat loss and muscle loss but can affect other hormones as well. People that already have hormone challenges are even more sensitive to this potential problem, and respond the best to the what I refer to as “monthly diet variation.”

Feasting for one week a month (as described below) not only helps the conversion of T4 to T3, but other hormones like estrogen and testosterone as well. The week before a woman's period is what we have discovered is the best time to drive the insulin up to assist in the many hormonal needs that take place at that time.

Think about how smart the body is. That is the time that most women would say they get the cravings for carbs and sugar. Simply listen to your body, but reach for the healthy carbs like fruits, sweet potatoes, yams, ancient grains, ground vegetables, etc. Men this has been a proven strategy for you as well just from a variation strategy to remind your body it has plenty and not starving, and from the variation of the increased carbs or protein drives a pathway called mTor which is an anabolic pathway for growth. This pathway is referred to by the low calorie, low protein and plant-based diet enthusiasts as a destructive pathway that can lead to premature aging and disease, however, clinically we find that short-term stimulation of this pathway from high carbs, protein or calories can have a healing effect and improve the hormones and metabolism.  

Diet Variation: 3-2-2 (great for anyone struggling with thyroid conditions)

Each week:

Pick 3 days of Intermittent fasting days:

Although it may sound complicated, intermittent fasting is actually a very simple concept. It’s eating in a 4-6, maybe 8 hour window. Maybe you start with a 10 hour window. I personally have been at it so long, I love to go at least 18-24 hours. Therefore, my eating window is typically 4 hours. However, I don’t recommend beginning with a long fast right away. You have to work up to that efficiency in the cells, which is why we I created this program. Be patient and work your way up. As you get more fat adapted, you will burn more fat for energy, and you will be able to fast for longer periods. The idea is to do a short daily fast, only eating during certain hours of the day.

Pick 2 days of famine: 

Famine means just water for 24 hours

Pick 2 days of feasting:

Do not limit your intake of food or water, eat throughout the day.

**Tips to remember:

  • We want to see glucose dropping, and ketones rising, even when varying and cycling the diet!  
  • As we see that happening, then increase fast days per week.
  • Don’t forget about the feast days, which are just as important.
  • Wait until you are in ketosis to start the feast famine cycle.
  • If you are coming off the water fast, you don’t have to wait, go right into feast famine cycle.
  • Monitor glucose levels! Autophagy will still keep going, as long as glucose isn’t rising. You have to look at the glucose.

Diet Variation: Monthly 

7 carb loading days/month:

Listen to your body: Do the carb day when needed.

  • Add in 1 carb loaded week, where ever you have the most moodiness and carb cravings. For females, this is typically the week of menstruation.
  • Remember, low carb for a long time keeps insulin low. However, chronically low insulin (especially for those who are hormonally challenged) will start to slow down the conversion of some hormones.
  • T4 hormone (the non-active thyroid hormone) has to convert to the active form of T3, which is the kind that has to go into the cell receptors in the mitochondria and talks to the receptors.
  • This conversion requires insulin.
  • Really healthy people can get their insulin down to 2 and below, and can still make that conversion. However, for those with hormone conversion trouble already, when the insulin gets too low will start to slow down this conversion, and not make the active form.

We need insulin to make many hormone conversions.

Once a month adding in these carbs (through diet variation), we magically start converting our hormones and feeling better! This applies to the rest of the month. This is imperative for those people with thyroid conditions. Fasting and diet variation are both great ways to increase your thyroid health, in conjunction with my multi-therapeutic approach to healing.


1. Cancer Stat Facts: Thyroid Cancer.

2. Hypothyroidism (Underactive Thyroid).

3. Hyperthyroidism (Overactive Thyroid).

4. Comparative Study Of Pituitary-Thyroid Hormone Economy In Fasting And Hypothyroid Rats.  1985 Feb;75(2):679-88.

5. Different Levels Of Thyroid Hormones Between Impaired Fasting Glucose And Impaired Glucose Tolerance: Free T3 Affects The Prevalence Of Impaired Fasting Glucose And Impaired Glucose Tolerance In Opposite Ways.  2014 Jun;80(6):890-8. doi: 10.1111/cen.12384. Epub 2014 Jan 16.