Extended healing fasts (14-40 days)

Dr Tallis Barker, water fasting coach

Why in the world would you ever want to fast for two weeks or more?

If only a tiny percentage of people in the Western world ever undertake a water fast of any kind, then only a tiny percentage of people who water-fast will ever undertake an extended healing fast of 14 days or more. Why? There’s simply no need. For everyday cleansing and healing, occasional 7-10 day fasts combined with regular short fasts such as the one-day (36-hour ) water fast should keep you in excellent health.

Benefits of extended water fasts (14-40 days):

However, in order to reach the deepest possible level of healing and reap the greatest benefits, it is necessary to dig deeper with a longer fast. For instance, certain serious physical illnesses – those often deemed incurable by Western medicine – require the cleansing of an extended fast in order to permanently heal. Despite what allopathic doctors may tell you, conditions as wide and varied as Type II diabetes, multiple sclerosis, chronic high blood pressure, autoimmune disorders, as well as certain types of tumors are all potentially curable. Yes, these illnesses and many more can be healed permanently through water fasting. As a water fasting coach, I’m privileged to witness this miraculous healing potential of the human body!

Beyond physical healing, the deepest spiritual cleansing can similarly take place only through the sheer length of an extended fast. Although nowadays we tend to remember only the Biblical 40-day fasts of Moses and Jesus, the fact is that many spiritual traditions over the millennia have demanded 40-day water fasts. Even Pythagorus required potential students to undertake a 40-day fast before he was willing to accept them. As much as we balk at the idea of giving up food for such a long time, it’s mostly just a question of unwillingness to forgo the addictions and pleasures of life. Don’t believe the voice of your fears and reluctant ego. You won’t starve to death. Unless you’re seriously malnourished and underweight to begin with, you carry the better part of 100,000 calories on you, locked in your fat tissue and waiting to be released through ketosis. That’s enough to last you well over 40 days. If you’re overweight, you could potentially fast for much longer (although in most cases this is not advisable).

Experiencing a healing crisis:

Although in one respect an extended fast simply continues the notion of a 7-10 day water fast, it is also much more powerful because it gives you the opportunity to experience deeper ‘healing crises‘. As described in the article on the 7-10 day water fast, a healing crisis often occurs towards the end of the first week of water fasting, as the symptoms of old illnesses, injuries and traumas resurface, before being permanently expelled from your body. A similar process often occurs around the end of the second week of fasting – and this is the reason that if you decide to extend a 7-10 day water fast, it’s worth aiming for at least 14 days. This second healing crisis tends to call forth deeper issues than the first healing crisis, or, alternatively, finishes resolving those issues which were not fully cleared during the first healing crisis. In other words, it’s from the beginning of the second week of water fasting that your body can begin to heal from more serious health issues. Simply, up until this point, your body has been cleansing the toxins of everyday life (and especially so if you haven’t been fasting regularly).

For the deepest and most serious health issues, whether physical or spiritual, healing crises often occur much later into the fast, whether 20, 30 or even 40 days. There’s no way to accurately predict when they will occur. You can only trust your body and let nature take its course…

Occasionally, healing crises can be extremely intense, especially when they occur late into a fast. When this happens, it’s critically important to be able to (continues below)


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tell the difference between a healing crisis and a sign from your body urging you to stop the fast. This is where working with an experienced water fasting coach can really help. If it’s a healing crisis, you should ideally try and push through. If it’s not, you should stop immediately!

Not every healing is accompanied by a dramatic healing crisis. Sometimes symptoms of illness and trauma simply begin to disappear. In cases like this – when no clear sign indicates that you’ve obviously freed yourself from a health issue – it can be difficult to know when to end the fast. This is another reason why it’s advisable to consider conducting any extended fast under some kind of supervision: from (1) a fasting coach like myself and, ideally, also from (2) a medical doctor who understands water fasting. The other main reason for working with a professional is to make sure you don’t overstep your body’s nutritional capabilities, as a prolonged fast begins to reach its physical limits.

The dangers of fasting too long:

If you continue fasting indefinitely there comes a point where the fast turns into starvation. You obviously don’t want to overstep this mark! For when your fat stores are finally depleted, the body has no choice other than to devour muscle tissue, as well as feed from your inner organs. You’ll do yourself serious damage. Fortunately, though, the body sends a clear sign: extreme hunger. Although it’s unlikely you’ll miss this red flag, two other less obvious scenarios also demand the end of a fast – and it’s here, again, that fasting under supervision can help. The first possibility is that you run out of muscle tissue before you deplete your fat stores. In order to power your body as a whole, it’s true that ketosis is extremely efficient. The problem is that the brain demands another fuel entirely: glucose. And this cannot easily be metabolised from fat tissue. Instead, the body must extract it out of muscle. The second possibility is that you deplete your electrolytes (blood salts). Although unlikely, it’s extremely dangerous! For this reason it’s advisable to have your blood tested at relatively regular intervals after the first 7-10 days of fasting.


After you break an extended fast, it’s extremely important to follow a well structured meal plan. If you return too quickly to a normal diet, you risk encountering both digestive problems as well as ‘refeeding syndrome’. This is a potentially fatal complication caused by the change from ketosis back to your everyday metabolism. After an extended fast, the body cannot be rushed in this process. If you have any doubts, I offer a downloadable PDF which covers refeeding for any length of fast (link here).


— Self-healing: stronger than any pill (click here)
— Deeper states of consciousness (click here)
— Facing your ego (click here)
— Who am I? (click here)

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  1. Jeanne-Christele says

    Hi Tallis, thank you for this article. I had been fasting for 14 days when I got my blood work with high uric acid marks just above the allowed limit. I stopped the fasting slowly the next day. I barely eat any red meat , but I devour seafood, fish and canned sardines.
    Would you advise me to try waterfasting again or just work on my diet for the time being?

    • Tallis Barker Ph.D. says

      Hi Jeanne-Christele,

      Thanks for your question. Meat and fish can certainly increase uric acid, but for me the issue here is the context. What is ‘normal’ for blood work while fasting is often different from and can’t be fully compared to that in everyday life. Uric acid levels, for instance, can easily increase due to the cleansing. So if your uric acid levels were only just outside the ‘green’ zone, then it may not really have been a problem at all.

      It would be interesting to know what level the uric acid was at before the fast, because this, in essence, would give you the answer to your question. If they were high to begin with, then it would make sense to work on your diet, whereas if it was simply a consequence of the fast, then it would be more effective to continue to practise fasting. In either case, lowering meat/fish intake before a fast to lower gut acidity is always a good idea!

      Hope this helps,

  2. Latrina says

    Hello.. I would like to know your thoughts on dry fasting.

  3. Dan says

    Dear Dr. Tallis,

    Thank you so much for providing this information for us water fasters online. I am currently on day 6 of 7 of a water fast and I add slats, magnesium and potassium to my water. I have completed a water-only fast last year for 5 days but was extremely fatigued and could barely sleep, hence the salts this time around. They seem to have helped mildly this time round. Furthermore, weight loss, which is not my goal, has been very drastic, loosing 6 kg in 4 days. I came into this fast with a BMI of about 23 and now stand at 19.8. Also vegan before starting the fast.

    I am fasting to attempt to improve Peyronies disease, a calcification (plaque) in the penis, which can be felt and is about the size of a small rice grain. From what I can say at this stage, there does not seem to be much improvement yet.

    Could you shed some light on whether extending this fast to 10 days + or incorporating more frequent (shorter) fast over the years would be more suitable?

    I highly appreciate your advice and should have booked your coaching session before fasting.

    Kind regards,


    • Tallis Barker Ph.D. says

      Hi Dan,

      Thanks for writing. If the main reason for fasting is to heal from Peyronies disease, there’s no question in my mind that it would be more effective to aim for a long fast. Whether this is the right time to be undertaking that fast is another question. In order to get the most out of an extended healing fast, for instance, it can be beneficial to eat a cleansing diet for a certain period of time beforehand (depending on your current diet). A lot also depends on how much you’ve fasted before.

      In terms of the salts, I would get off them! Salts / electrolyte supplements are one of the big fallacies of fasting. Certain well known authors promote them, though, because they do make you feel better, with higher energy levels. In short, salts are an easy and popular sell. Unfortunately, though, the truth is that such supplements lower the degree of cleansing. I see this the whole time with clients who choose to use them. Especially as someone fasting to improve a health issue, though, you want to get the most out of your body’s full potential!

      One final thought: fasting tends to heal soft tissues the quickest. For harder tissues and issues relating to crystallisation (and calcification would fall into this category), you’d need considerably longer than 10 days to stand a real chance of improving your condition. This isn’t to say it’s impossible, but consequently the previous issues I’ve mentioned above are all the more important to consider.

      All the best,

  4. Terri says

    Hello Tallis, As this is your area of expertise. I am hoping you can clarify the back pain I was having. My husband and I decided to do a 7 day fast. I can do a 1-2 day fast with no issues. The most I had previously done was 3 days without any unusual issues. However on day 4 of this fast I was getting pain in what felt like both of my kidneys. It didn’t feel normal so I stopped the fast. I have read online that others have also had this issue, but no one really knows what it is. Some say it may be a kidney detox, but it didn’t feel that way. Have you come across this phenomena? I would like to attempt at least a 14 day fast, if not longer, but would like to get this issue clarified before I start.

    Thanks for any insight you may provide
    Terri Garringer

    • Tallis Barker Ph.D. says

      Hi Terri,

      Ah yes, the mysterious ache in the lower back… I’m guessing that you feel it especially in the soft area between the top rim of the pelvis and the lowest ribs.

      Yes, I often come across this issue with my clients, and at times have suffered from it myself when fasting (especially dry fasting). In fact, I’d say it’s one of the most common detox symptoms after the first few days of fasting. Like everyone else, I used to assume that it was the kidneys, but have since come to the conclusion that it’s actually sensitive lymph ducts and nodes.

      The first thing to do is to dig out an anatomical diagram and take a look at where the kidneys actually are. The vast majority of the kidneys’ surface area is protected by the ribs – that is, they are NOT located in the soft area between pelvis and ribcage, as many people believe. They are higher, in an area which does not correspond to where most people feel this ache.

      The second thing to do is to look at an anatomical diagram of the lymphatic system. The lymph ducts from the legs join near the top rim of the pelvis, along with a lot of lymph nodes in this area (for cleansing!!!), before moving up through the lower back. This is precisely the area where most people feel the ache during fasting. And if you actually palpate the area while suffering from the ache, you’ll realise that the source of the pain often feels like it’s coming precisely from behind the top rim of the pelvis. Voila!

      The solution, therefore, is to help flush the lymphatic system – especially since it works so hard during a fast to cleanse your whole body.

      In a smaller number of cases, people do feel their kidneys, and my theory was implicitly proven recently thanks to a client who suffered simultaneously from both the lymphatic ache as well as the kidney ache. He was able to distinguish between the two sensations both in terms of their location and quality of the discomfort.

      Although uncomfortable (and sometimes almost unbearably so), this phenomenon is very normal indeed. The best thing is to facilitate lymphatic cleansing before symptoms appear, rather than waiting until it’s too late. An ounce of prevention… In this respect, movement and heat tend to be the most effective modalities. The more systematic you can be, the better!

      Hope this helps,

  5. Justin Williams says

    Hello and thanks for all the useful information. I thought I was a trooper for a couple of three day fasts over the past couple of years, lol…humbling to read about all of the extended fasting. I’m curious to know if discerning between “true hunger” and not true hunger is a common dilemma experienced with extended fasting. Also, I broke my thumb about two years ago. I didn’t allow it to heal properly and so at the base of the thumb there is built up tissue…or something, and seems pretty permanent. I’d like it be like it was before the break. In your opinion does extended water fasting help with dissolving the excess tissue of a broken bone that never healed properly?

    Many Thanks

    • Tallis Barker Ph.D. says

      Hi Justin,

      Glad you found the website useful. First, you ARE a trooper to have done a couple of 3-day fasts, because this goes way beyond what most other people in the world have ever done. To answer your question: it’s not hard to distinguish between ‘true’ hunger when you’re down to 1.5-2% body fat and other types of hunger!

      Otherwise, water fasting promotes healing across any and all body systems and tissues. Unfortunately, though, it does tend to work the slowest on dense, hard tissue like bone. If the specific problem isn’t the bone itself, but rather scarring or related muscle/nerve damage around the bone, then water fasting will be much more effective.

      Hope this helps,

  6. Veronica says

    Hello… I’m on day 5 of a fast, drinking distilled water and decaf coffee. My ketones are 8.0 mmol/L on the urinalysis scale.

    Is this too high?

    Thank you

    • Tallis Barker Ph.D. says

      Hi Veronica,

      Your ketone levels are totally normal for Day 5 of fasting. Basically, you don’t ever need to worry about ketones ever being ‘too high’ when fasting. In fact, the higher the better, since it means you’re more efficiently accessing your fat stores.

      Just one other comment. I’d stay away from coffee when water fasting, regardless of whether or not it has caffeine. Coffee is highly acidic in the gut, and this induces a mucous response from the lining of the intestines – and all the more so when there isn’t any other food in the gut to soak it up. This ‘goops up’ the intestines, instead of leaving them as clean as possible to facilitate in receiving certain toxins from the blood.

      All the best,

  7. Deepika Gupta says

    I had embarked on a 26 day fast two years ago and on the 7th and 8th day I started throwing up any water I drank. I was sipping it. I also started throwing up blood. So I got scared and ended the fast. Is it a normal thing to throw up blood as part of the detox? All vital signs were normal.

    • Tallis Barker Ph.D. says

      Hi Deepika,

      If you’re a totally healthy person, you shouldn’t normally throw up blood while water fasting. Something obviously started happening on the 7th and 8th days to cause you to start throwing up, but without having followed you through the fast it’s hard for me to guess why this happened. It’s more normal to throw up bile, which can colour the vomit yellow or green. The specific colour of the blood would also help to identify the source: throat, esophagus, stomach or even lower down in the digestive tract, and this in turn might suggest the cause of the problem.

      All the best,

  8. Kathleen Hiler says

    I am on day 36 of a 40 day water only fast..had been having issues with nausea a lot after the first healing crisis 10 days in..still had been able to be busy cleaning cupboards etc to prepare for different way of eating when finished.. tonight the belching I have been experiencing led to a session of vomiting..a yellowish liquid..mostly watery..that irritated my throat a bit..I actually felt better after it was over. I want so much to do the 40 because of what you said about Deepest possible cleansing and healing physically and spiritually..I had started the fast..I felt from the Lord before I came across your article. There have been healing issues come up..on Good Friday morning I went to be with the Lord and I cried and cried over trauma done to my “little girl” inside.. and actually a joy that THIS TIME it was over..and being freed from a mental emotional “tormentor” Doctor..the battle has been very great..in my life and during this time..I just so need to hang in there for 4 more days..I take a thyroid pill each day..which had begun to be reduced several times already..I am thinking to stop the thyroid at least one day.. because ithink that is what I threw up..not to worry because I have been very over weight..I am 71 years old and am counting the next 4 days to the finish !

    • Tallis Barker Ph.D. says

      Hi Kathleen,

      Thanks for sharing. It sounds like, in every respect, you’re going through a very powerful journey – as 40 day fasts tend to be!
      Nausea caused by cleansing can occur at any point during a fast – even late on into a 40 day fast. However, if it becomes persistent to the point of frequent vomiting, this can also be a sign that it is time to end the fast. It’s extremely important to respect the body if this occurs!

      I can’t comment here on your specific thyroid medication, except to say that during extended fasts it certainly does often become possible to reduce dosage if not completely eliminate it. (You should discuss this with your doctor first.)

      Wishing you all the best for the remainder of your fast!

      • Kathleen Hiler says

        I am asking if drinking herbal tea to quiet nausea would help..or is that breaking the water only fast..I sip water only when the nausea hits me and I threw up again yesterday afternoon and 12 hours later this morning..I got some filtered water from a sister who had a filter device..I had used the filter on my fridge..but after a few swallows of water..I use a cup with a straw in it.. I start belching the water..but I can’t help but think I have only 2 more days to go..

        • Tallis Barker Ph.D. says

          Hi Kathleen,

          Drinking herbal tea does won’t impact on ketosis, so in physical terms you don’t break your water fast. In terms of fasting for spiritual reasons, though, there are implications. A big part of spiritual fasting involves taking away taste, because in order to discover who you really are, it’s important to eliminate external stimuli and addictions. After 38 days, though, I wouldn’t worry about this too much! It’s a very minor issue at this point, and you’ve already proved you can do this!

          You should know that, among the many causes of nausea during a fast, one is sipping your water instead of drinking it less frequently and in larger quantities (although I’d always recommend drinking to thirst and not according to some random number you ‘think’ is good for you). Just thought I’d mention this since you yourself mention ‘sipping’.

          All the best,

          • Kathleen Hiler says

            Thank you for your response Dr.Barker..i did consider the “taste”aspect for the spiritual side of this journey..which was why..I feel..I was led to embark on this water only fast in the first place..the “deepest possible cleansing and healing” but felt that it was an honest assessment to do the peppermint tea to help with the nausea..
            the “sipping” was all I could do as there was no real thirst at all by then and I only sipped to deal with the nausea..to try to stop throwing up..the tea helped..but the nausea was still there.. and the belching from sipping it..but I didn’t throw up yesterday..today is the last day..

            tomorrow I feel led to partake of tiny amounts of Idaho potatoes..soft veggies like broccoli and cauliflower. I thought the potatoes sounded right as they have all 9 of the essential amino acids potassium and phosphorus..etc etc

            I appreciate your article about this..I appreciate all of your responses to and having read your responses to others..they are so helpful to all who find their way here. I could not go back on the thyroid meds..the vomiting issue. I will just have to deal with that one at the end of the month when labs are done again.

            I believe Hashimotos.. kidney issues with adrenal insufficiency..knees ankles already mobile..right ankle was shattered 37 years ago..left knee surgery..sinusitis.. spiritual “tormentor” tried to come back this morning..Nada stopped eating meat January 28 in this journey..in favor of elk deer or wild caught kosher fish..or veggies..no restaurant oils etc etc ..
            Thank you again..

            • Tallis Barker Ph.D. says

              Hi again Kathleen,

              I think you say it best when you say it was an ‘honest assessment’ to include the peppermint tea.

              When it comes to refeeding, please be very careful about not including too many calories too soon – which means going very easy on the potatoes for a while. Too many calories after an extended fast can bring on refeeding syndrome, which is something you definitely don’t want want to encounter. The first symptoms are muscle cramps (typically in the hands/feet) and oedema. This can lead to nausea and ultimately death through cardiac failure, if refeeding continues unabated over too many days, while ignoring the symptoms.

              Focus on leafy greens first! If you need any guidance on refeeding, there’s a pdf on the waterfasting.org which deals with this at length:

              All the best,

  9. Dana says

    I am a middle-aged female on day 21 of a 30 day water only fast, and one of the greatest challenges I have faced is a horrendously itchy ketosis rash all over my chest and abdomen. All the online advice I read says the only cures are oral antibiotics or eating carbs. I have tried topical antibiotics and cortisone cream with no results. I keep it hydrated with aloe vera lotion. Any other solutions I haven’t thought of? I am determined to make it to day 30, but this rash increases the difficulty exponentially!

    • Tallis Barker Ph.D. says

      Hi Dana,
      The fasting rash is problem for a lot of people, and I literally see it a lot among the participants on my fasting retreats. Personally I wouldn’t call it a keto rash because I don’t believe it has much to do with ketosis (FYI there’s no official explanation re. the cause). It seems to me that it’s more likely due to the release of toxins through the skin, which causes irritation, redness and sometimes itchiness. This also explains why it can occur after the fast once ketosis has reduced or finished but while the body is still in the final stages of detoxing. It also explains why antibiotics and creams don’t help. Keeping it hydrated is good, but it’s also important not to block the pores with anything which might cause the toxins to become trapped in the skin.
      Hope you feel better soon,

  10. Brandon Stark says

    Hello I just started my first 40 day fast on Sunday. When I tell people I am doing this they all say you wont have enough vitamins and you will get sick. Should someone take vitamins while water fasting/ will my body deplete of essential vitamins and minerals?

    • Tallis Barker Ph.D. says

      Hi Brandon Stark,
      There are a lot of nay-sayers out there when it comes to water fasting. Of course, it’s because the vast majority of people are afraid of giving up eating, and this can translate into fears about pretty much anything with regard to fasting. The body does conserve its resources while fasting, though, and this includes vitamins. So long as you’re generally healthy (with no metabolic problems or absorption issues) and you eat a generally healthy diet, you should be just fine without any supplements. Thousands if not millions of people have been equally fine over the millennia on their own 40-day fasts.
      I’m glad that like a true Stark, you’re braver than the nay-sayers!
      Best of courage and strength to you over the next 40 days.
      Spring is coming!

  11. Yus says

    you only in danger when your body fat falls below single digits, than yea stop.

    • Tallis Barker Ph.D. says

      Hi Yus,
      When your body fat falls too low, you’ll know because you’ll feel true hunger return. It’s only if you ignore this very clear sign that you’ll get into danger.

  12. Gary says

    Refeeding first day after 18 days and urine is light brown

    • Tallis Barker Ph.D. says

      Hi Gary, changes to the colour of urine can be normal, but I can’t comment in greater detail without more background information (and this isn’t really the place to get into specific individual cases). The key to a successful refeeding program is in breaking a long fast gently, following this up with a gradual increase to the spectrum and quantity of what you eat. After such a long fast you should be eating only vegetables (and perhaps a little fruit) today!
      All the best,

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