Fasting Can Help Reverse Autoimmune Disease – If You are Mindful of Cortisol

Feb 19, 2023 | autoimmune disease, autoimmune disease prevention, cortisol, Fasting, Fasting mimicking diet

Fasting to reverse autoimmune diseaseFebruary is National Fasting Month and we are going to dive into the topic of fasting while keeping cortisol in mind.

Cortisol is an extremely important (if not the most important) hormone and without healthy cortisol levels, reversing and preventing autoimmune disease is almost impossible.  Now does that mean no fasting?  Not at all.

Research into the health benefits of fasting has been ongoing since the early 1900s.

  • One early example of research into fasting was a study conducted in the 1910s by Dr. Edward Dewey. Dewey conducted a series of experiments on himself and several other individuals, in which he fasted for various lengths of time and recorded the physical and mental effects of fasting. He reported improvements in a variety of health conditions, including rheumatism, high blood pressure, and digestive issues.
  • In the 1960s, Dr. George Cahill and his colleagues at Harvard Medical School conducted a series of studies investigating the metabolic effects of fasting. They found that during fasting, the body begins to break down stored fat for fuel, which can lead to weight loss and other metabolic changes.
  • More recently, a number of randomized controlled trials have been conducted to investigate the health effects of fasting. One study published in the Journal of the American Medical Association in 2017 found that alternate-day fasting led to significant weight loss and improvements in markers of cardiovascular disease risk in overweight adults.
  • Another study published in the New England Journal of Medicine in 2019 investigated the effects of a 3-month period of time-restricted feeding, in which participants were only allowed to eat during a 10-hour window each day. The study found that time-restricted feeding led to significant improvements in blood pressure, insulin resistance, and oxidative stress in participants.

How Cortisol is Impacted by Fasting

Fasting has been shown to cause hormetic stress, which can help to strengthen the body. Hormesis is a beneficial response to a low dose of a stressor, and cortisol is a hormetic response to fasting. However, if cortisol remains high for extended periods, it can have the opposite effect of fasting.

Research has found that varying the length and type of fast can help prevent consistently high cortisol levels. 

For example, one type of fasting protocol known as “One Meal a Day” (OMAD), involves eating only one meal per day, which can lead to consistently high cortisol levels.

After around 13 hours of fasting, cortisol levels start to rise, which is a natural response to the body’s need for fuel. However, a little cortisol is generally considered to be a beneficial hormetic response to fasting.

Varying the length and type of fast can help to prevent consistently high cortisol levels, which can have negative effects on the body.

Several studies have investigated the impact of fasting on cortisol levels. One study found that alternate-day fasting did not increase cortisol levels in healthy individuals, while another study found that fasting during Ramadan did not significantly affect cortisol levels in healthy individuals.

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For those seeking the benefits of longer fasting, but going without food is too challenging or not possible, consider the Fasting Mimicking Diet available in my online store. It is a five-day diet that restricts calories and macronutrients in a way that mimics a water-only fast.

The Fasting Mimicking Diet has been shown to promote numerous health benefits, such as reducing inflammation, improving immune function, and promoting cellular regeneration. In a randomized controlled trial, participants who followed the Fasting Mimicking Diet for three cycles experienced a reduction in risk factors for age-related diseases, such as diabetes and heart disease.

Another study found that the diet led to a decrease in abdominal fat, which is associated with a higher risk of metabolic diseases. Overall, the Fasting Mimicking Diet may be a good option for those who want to reap the benefits of a longer fast without giving up food entirely.

The benefits of fasting are clear.

Fasting has been found to provide a variety of benefits, including:

  1. Improved metabolic health: Fasting can improve insulin sensitivity, reduce blood sugar levels, and lower the risk of type 2 diabetes.
  2. Weight loss: Fasting can help you lose weight by reducing calorie intake and increasing fat burning.
  3. Reduced inflammation: Fasting can reduce inflammation in the body, which is often linked to autoimmune disease.
  4. Improved brain function: Fasting can improve cognitive function, including focus, memory, and learning.
  5. Lowered risk of chronic diseases: Fasting has been associated with a reduced risk of chronic diseases such as heart disease, cancer, and Alzheimer’s disease.
  6. Longer lifespan: Studies have suggested that fasting may extend lifespan and delay aging processes through the processes of autophagy, improved mitochondrial function and stem cell production.

You want to make sure to vary your type of fasting, don’t get stuck in just one fasting routine.  Dr. Mindy Pelz is an expert on women fasting according to their hormonal and/or menstrual cycles.

When fasting times are varied, you can still reap the various benefits while helping to ensure that cortisol does not stay elevated for too long.

As always, before starting any fasting protocol consult with your doctor (ideally, they are experienced in functional medicine and have read my book, The Nurse Practitioners’ Guide to Autoimmune Medicine: Reversing and Preventing all Autoimmunity.)

“Got a Revolution, got to Revolution.”  Jefferson Airplane


Dr. David Bilstrom
Autoimmune Functional Medicine Doctornatural treatment for autoimmune disease by Dr David Bilstrom Functional Medicine Doctor MD



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