Is Water Only Fasting Safe?

Fasting was believed to be deadly

It wasn’t that long ago when it was believed that man could only survive about 7 days without food.  It was stated as fact; how long someone could last without air, how long someone could last without water, and how long someone could last without food.  I remember being taught that Jesus fasting for 40 days was a miracle, because no one could last that long.  I guess no one really wanted to test the hypothesis and see how long it took for someone to die.

In more recent years, people have tested the waters, so to speak, and have found that it is possible to live without food for extended periods of time.  In fact, one man had enough extra weight on him to be able to fast for over a year!  (Don’t try this at home, kids!)

Thank Goodness for Research

There has still been a lot of skepticism in the medical community regarding fasting, but some brave doctors have done some great research lately, and fasting has become more widely accepted; at least it’s starting to become accepted in the research community.  You may have heard of Dr Jason Fung, and his book “The Complete Guide to Fasting” (he actually has several books out now); or the research of Dr Valter Longo, who found that after day 4 of fasting, the body starts producing stem cells.  These men have done extensive research regarding the benefits of water only fasting, and believe it or not, their subjects didn’t die!  Ironically, Dr Fung, who is a Nephrologist (kidney doctor) dealing with diabetics, chose to fast his clients, because in the National Health Care in Canada, he wasn’t allowed to prescribe a specific diet for his patients to follow.

Holistic Health and Fasting

In the background, there have been water fasting centers, where people have gone to actually heal from some form of disease, or at least start on a healing journey.  For over 30 years, places like the True North Medical Center has been providing medically supervised fasts to allow people to reduce blood pressure, come off diabetes medications, reduce cancers, lose weight and the problems that come with that, and various other problems.  These centers have known for a long time that water only fasting has helped many people, but they had to do their work in the shadows.  Now that research is supporting their theories, they are able to support their claims of what they have experienced for years.  Keep in mind, these centers have extensive experience, and have learned a lot of lessons.  

Recent Experience with Fasting

After listening to many interviews with both Dr Fung and Dr Longo, I decided to do more research into the idea of fasting.  I personally accomplished two 5 day fasts in 2018, where I learned several interesting things about fasting.  One, it is both harder and easier than it sounds.  Two, if you are on medications, it is a good idea to do a medically supervised fast.  Dr Pompa ( has some great information on self directed fasts, up to 5 days.  Watching his videos and being part of his facebook page helped get me through those two fasts.

Then I found the research of the True North Health Center, and found that Dr Goldhammer has extensive experience with water only fasting, in a medically supervised environment.  His knowledge goes beyond just the benefits of water only fasting, but in the book he co-authored with Dr Doug Lisle, “The Pleasure Trap”, he understands the lure of processed foods, and the benefits of fasting to break the cycle of addiction to those foods.

Research on Adverse Side Effects

The benefits of having a program set up to provide medically supervised fasts, the True North Health Center has opened a research facility to allow them to use this expertise to provide the research needed for the medical community to accept water fasting as a viable treatment.  Of course, the obvious research for them to start with is “Is Fasting Safe?”, which is the name of their latest research.  (Actually, it’s “Is fasting safe, a chart review of adverse events during medically supervised, water-only fasting.”)  In this research, they document some of the side effects of fasting.  I could give you details and specifics, but I’m afraid it may be a bit dry, so let me give you the highlights.

Adverse events were categorized into five categories from mild to severe.  Most of the events recorded were mild, such as fatigue, insomnia, nausea, headache, feeling faint, back pain, extremity pain…which are known to occur during fasting.  (I’m sorry, sometimes I just want to say “DUH!”, when research statistics are presented.)  However, out of 768 patients, with a median fasting length of 7 days, there were only 2 severe side effects.  One was a grade 3 dehydration event that occurred in a 73 year old male on fasting day 3.  The other was a grade 4 hyponatremia (low sodium) event in a 70 year old male on fasting day 9.  Both patients were hospitalized and received intravenous fluids and recovered fully.  The conclusion of the study is that fasting can be implemented in a medical setting with minimal risk of serious adverse events.

Long Term Strategies: Intermittent fasting or Whole Natural Foods

In doing this research, I have learned quite a lot, much of it from experience.  Dr Goldhammer says fasting isn’t the best way to lose weight, and I understand why he says that.  Someone can do a 5 day fast and lose some weight, but often they go back to eating the same foods that caused them to gain that weight, and what have they learned?  They can get their fasting glucose down for weeks or months, but it will come back up if they eat the foods they ate to get their numbers up.  Their blood pressure can drop for a while, but it will go up again if they don’t change their eating pattern. 

Continued Fasting and Intermittent Fasting 

Dr Pompa suggests a ketogenic diet, with intermittent fasting, and weekly fasting to keep weight down and all the problems associated with excess weight.  If that is the method that appeals to you, then read Dr Jason Fung’s books, he has some great information.  This is probably a good approach for people who really don’t want to change their way of eating.  They would rather eat one meal day of what they enjoy, than to make significant changes to their diets.  Unfortunately, the longest research I have found on this approach has been for six weeks.  There is no long term research done on ketogenic diets, and what the long term effects are on overall health; such as blood pressure, arterial plaque, heart attacks and diabetes complications.  There is research that long term calorie restriction is beneficial to longevity, so maybe there is hope in that field; I’d just like to see some research accomplished over a long term, such as 6 – 10 years.  One benefit of weekly fasting and intermittent fasting…they are completely free to anyone who chooses to use them to benefit their health.   Not only is there no expense of going to a facility, you also cut down on your food bill, so having money is not requirement.

Whole Natural Foods (No processed foods)

If you prefer to eat daily, and are willing to change your eating habits for overall long term health, I believe Dr Goldhammer has some great answers.  In the book mentioned earlier “The Pleasure Trap” it’s made clear that in the processing of foods, there are chemical additives added to the foods to make them hyper palatable (I bet you can’t eat just one).  The chemical additives are processed sugar, processed sodium (salt), and refined fats and oils.  These chemical additives are extremely addicting, releasing dopamine into the brain and creating a drug-like need to keep this stimulation constant.  In other words, that’s the reason people will drive to the grocery store because they “have to have” their ice cream at night; or when they eat pizza, they eat until they can barely move; or they eat the whole bag of chips.  Often these people are accused of not having “will power”.  That’s like handing an alcoholic a beer, and if he keeps drinking, calling them “weak”.  No, they are addicted.  What we seem to have in this country, is a spectrum of addiction to chemical food additives.    Some people can eat just one Oreo or one potato chip, others will eat the whole bag.  Obviously, the excess in calories will create a weight gain, causing obesity or at least an increase in weight.  So it’s no surprise to see the statistics of the country indicating a steady rise in overweight and obese individuals, along with all the medical complications that accompany those situations.


Oddly enough, the answer is simple, but absolutely not easy.  If someone is addicted to a chemical substance, we don’t tell them to just cut down on their injections of heroine, we tell them they have to stop altogether.  Cutting out sugar, salt and oils are not as difficult as quitting heroine or alcohol or maybe cigarettes, but it certainly isn’t easy.  Here is where the fasting centers can really help.  Cutting out the chemical additives from the food  for a period of time can allow us to fully appreciate the true flavor of whole and natural foods.  Patients often find that steamed zucchini tastes amazing after a 7 day fast.  The brain can settle back down into a natural need for real food.  This can help a person change their eating habits over the long run, and as a consequence, improve their health long term.

Benefits After a Fast

The actions taken after a fast are what affect a person’s long term health and weight.  If after a fast, the person reverts back to their unhealthy way of eating, the only benefits will be short term benefits.  However, if they use that time of fasting to reset their desire for whole natural foods, it can be a long term, life changing event.  

Is Medical Supervison Required?

From everything I have read and listened to, the doctors all indicate that in a healthy individual, with no medications, anything up to 5 days is safe in a self administered setting.  Some say that exercise is allowable or even beneficial, others say a setting of complete rest is required.  I would suggest the environment of rest if you are planning on anything over 3 days.  The side effects of fatigue and discomfort need to be expected, not ignored.  However, some people have so much energy they can’t help but use that energy, especially on the second day.  All the doctors are fairly adamant that anything over 5 days needs to be medically supervised, by someone with experience in fasting.  Mistakes are common, whether the patient worries about common side effects, or doesn’t worry enough about symptoms that may indicate a need to break the fast.  Also, a recovery period of half the duration of the fast is recommended.  At True North Health Center, if the fast is 7 days, there will be at least 3 days of gentle re-feeding.  I thought it was a bit cruel that they provide cooking demonstrations to those who are fasting…but the patients seem to love them, so what do I know?  

Important: Some People Cannot Fast

At True North Health Center, and every other medically supervised fasting center that I know of, a thorough review of a potential patient’s health is taken.  Some people are not allowed to fast with only water.  Some patients are only allowed to have strict limitation of their food intake, due to health issues.  So keep in mind, there are some people that should not fast at all.  If you have any question, you can contact True North and have a free consultation to see if you are even able to fast.  If you are on any medications, I suggest you do that before attempting any fasting at home.

My Personal Conclusions; Safety, Planning, and Purpose


I believe it’s absolutely safe for anyone who is not on any medication to fast for up to 5 days on their own.  I believe this is a normal course of human experience; we didn’t always have food available 24/7.  However, for anyone planning on fasting on their own, I strongly suggest doing a lot of research before attempting it.  I found that back pain was very common in those fasting over two days.  My blood glucose dropped to levels that would shock most people.  I don’t suggest you decide this is the time to do a heavy workout, to respect what the work your body is doing by releasing the stored toxins and fats from your liver and other organs.

If you have health issues, I strongly suggest going to a medically supervised fasting facility.  True North Health Center is completely vegan for many reasons, and if you don’t agree with that philosophy, you may choose a different one; perhaps a doctor trained by Dr Pompa.  I don’t know of any facilities, but having a doctor monitoring you may be enough.


One other important consideration: plan what you will do after the fast, starting with the day after your fast, or your first breaking fast meal.  Otherwise, you will have every excuse to binge on everything you know you shouldn’t be eating.  Our bodies will be searching for the highest calorie dense foods to make up for the famine they just experienced.  They want to restore the extra storage as fast as possible, so you will crave everything you have just worked so hard not to eat.  After body builders finish a competition, the most common food for them to eat, after weeks of calorie restriction, is pizza.  They also tend to gain about 10 pounds in a matter of days. I don’t suggest this type of plan.

What’s Your Purpose?

Most of all, know the purpose of your fast.  I did it mostly for the experience, to see if I should recommend it to anyone; that’s even a good enough reason.  However, I will say I agree with Dr Goldhammer; it’s not the best way to lose weight, unless you are using it to help you change your way of eating and lifestyle.  If you are using it to change your lifestyle, then it is an amazing start.  There can be other reasons, though.  Fasting has been shown to reduce blood sugars, blood pressure, and alleviate many complications of disease.  These can be great motivators, but will hopefully encourage those people to continue with better lifestyle choices.

If you have considered fasting or intermittent fasting, I hope this helps you understand that there is true scientific research showing it isn’t dangerous under certain circumstances.  It can be very beneficial, and I believe it has been a normal course of the human experience.  I encourage you to do some research to find out if it’s something you could benefit from.

If you have questions on this subject, or any that involve improving your health, feel free to contact me, or start a discussion on my Facebook Page.

To your health!

Patti Bealer
Health Advocate and Health Coach