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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The webshop offers downloadable fasting plans and guides to help make your water fast a success.

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. Ellie says

    Hi Tallis,
    I am on day 14 of my water fast and I am feeling very weak. I was not overweight to begin with and I am very skinny now. I feel mentally very very clear.. emotionally still processing a lot of anger. I have auto immune issues and have previously had cancer and chemotherapy (8 years ago). I am waiting for my tongue to turn pink and the white mucus to disappear. My tongue is getting pinker each day but isn’t quite fully pink yet. A little bit of fear is creeping in because I feel so weak and am very skinny and I don’t want to harm myself. I have prepared irish sea moss and was going to start with a teaspoon of that a day and I have started drinking a cup of chaga mushroom tea since yesterday, Are there any other vital signs from my body I can watch for to know when to break the fast. I was going to break the fast with some bone broth and watered down fresh tomato juice, Are they wise choices in your thinking?
    Kind regards

    • Tallis Barker, D.Phil. says

      Hi Ellie,
      Apologies for the delay in responding. There’s been a glitch with messaging on the website.
      It’s hard to comment on general signs about when to stop a fast… The first ‘classic’ sign is that hunger returns. I’ve never seen a client reach this point, although normal hunger can arise at any point during a fast. The second ‘classic’ sign is that the tongue turns completely pink. I’ve never seen a client reach this point either, although the tongue can and does change in its colouring during a fast. Having said this, there are definitely times when I’ve advised a client to stop a fast, but this has always been based on the individual circumstances of the client and the fast. If you’re ‘very skinny’ it’s hard to say more here without knowing your height and weight.
      Your plan to break the fast can certainly work.
      All the best,

  2. Melisa Macri says

    thank you for your time and effort supporting all of us. Do you take concern or issue with enemas during fasting. MMS or coffee?

    • Tallis Barker, D.Phil. says

      Hi Melisa,
      Thanks for writing. There are those who say you should never take an enema while there are those who prescribe daily enemas. I prefer a middle road, in which you take an enema if there are concrete signs of a build-up of toxicity in the colon. Otherwise, “if the wheel ain’t broken, don’t fix it.” When an enema is necessary during a fast, it should always be with plain water. Coffee enemas are far too strong on your liver, which is already working full power on detox. I’ve had numerous clients who have ended up with severe cramping because they’ve followed misguided advice about coffee enemas…
      Hope this helps,

  3. Tanya says

    Hi Tallis,

    I am going into Day 10 of my water fast, and tomorrow morning will complete my first 36 hour dry fast.

    In 2020 I completed a 40 (and a half!) day water fast, which went very well, in great part thanks to your website and your re-feeding booklet.

    I have several questions:

    • How much water do you recommend I drink per day?
    (I know I’ve read this on our website somewhere but can’t find it!)

    I’ve been getting acid reflux, mostly in the evenings (after drinking1/4 cup). I’ve not been diligent in keeping a record of what I drink, but it started off at around 1.8l and has reduced during the fast, as has my desire to drink. The day before my dry fast I drank around 800ml, which is the lowest it has been, and seems too low. That day I had some acid reflux in the morning, after drinking.

    The acid reflux is quite temporary.

    When I start drinking tomorrow, I feel I should make a point of sipping little, but often.
    • Do you agree with this?

    • Do you have any tips for dealing with acid reflux?

    Thank you so much!


    • Tallis Barker, D.Phil. says

      Hi Tanya,

      Congratulations on your first 36-hour dry fast – not to mention the 40 days on water 🙂
      When you finish a dry fast, it’s always a good idea to sip at least the first pint (500ml) or so. You don’t want to shock your system in a manner similar to finishing a water fast with a large meal! This leads to answering your other question: during a water fast it’s almost always best to drink to thirst. You may be surprised how little water you actually need after a dry fast – in the same way that people don’t get ravenously hungry after a water fast. I’m absolutely not suggesting that you should limit water intake here, just that you should really try to feel into what your BODY wants rather than what your MIND may be dictating about how much you ‘should’ drink following the dry fast.

      When it comes to acid reflux, there are multiple possible causes which make it difficult to go into here. With my clients, it’s the kind of thing we cover in daily coaching sessions, first identifying the cause and then finding a solution. Hopefully, your dry fast will have resolved the issue.

      All the best,

      • Tanya says

        Hi Tallis,

        Thank you so much for your prompt response!

        What you say here, really resonates: “you should really try to feel into what your BODY wants rather than what your MIND may be dictating”.

        I felt that my body was leading me towards a dry fast, as I did not feel like drinking. I wondered whether this would result in a “reset” that then allowed me to drink (more) with ease. So far, this is what is happening.

        I completed my 37h dry fast at 8am, and it is going well. I am drinking regularly and it feels good! I’m thirsty and feel like drinking again! No acid reflux. (I made a point this time round being mindful of my pre-fast meals and the last three days were liquid, to avoid food remnants as much as possible.)

        Fingers crossed, as you said, the dry fast seems to have resolved this issue. I love how your words align with my intuition/body listening-to.

        My question about water intake was about during a water fast (as opposed to after a dry fast). I’m sorry if my wording was confusing!

        – Is there a minimum amount of water I should be drinking?

        Thanks again for al that you do!

        Warmest wishes,


        • Tallis Barker, D.Phil. says

          Hi again Tanya,
          Actually, my previous answer applies here too: it’s almost always best to drink to thirst. In terms of a minimum amount to drink, there’s no fixed limit – it really depends on different people at different times in different climates, at different points in the detoxing cycle. If you had to put an absolute limit on it, though, I’d say that you need to drink at least a litre per day in order to prevent dehydration from setting in over the long term.
          Glad your reflux is gone!
          Keep listening to your body – it knows what’s best 🙂

          • Tanya says

            Hi Tallis, 

            It’s been 6 days now, and I continue to feel natural thirst and drink happily and easily.

Thank you so much for your responses and for answering my questions. Much appreciated!

            Here’s to listening to my body. 😊


Have a lovely day!


            • Tallis Barker, D.Phil. says

              Glad all is going well, Tanya!

  4. Juan says

    Hi, great insights! Thanks.

    I’m currently trancing the 6th day of a water fast (plus pink salt, green tea and black coffee, which I ditched on day 5 as I realized it put my gut to work.)
    Since yesterday I started feeling mild pain in every part of the body that had ever been injured/infected. (left lower back, right sciatic nerve/muscle, etc.). I assume it’s a healing crisis.

    When is best to end the fast? Would I ruin the process if I end it today/tomorrow (6/7d)?
    Given that I already had a “crisis” how necessary is it to push another week or longer?

    • Tallis Barker, D.Phil. says

      Hi Juan,

      Thanks for sharing. I’m glad you realised that black coffee is definitely a problem on extended fasts – in contrast to what some doctors who are well known for intermittent fasting (but who unfortunately don’t have much experience in prolonged fasts) have publicised…

      The kinds of pains you describe do sound like a healing crisis. By the way, next time you fast do NOT take salt if you want to maximise healing. Salt increases inflammation, which interferes with the healing process. Again, I don’t want to name names, but there are certain well known doctors who don’t recognise this, because they are acquainted only with shorter fasts in which salt intake doesn’t make much difference.

      To answer your question, the best time to end a fast is when you’re not in the middle of a healing crisis. This might mean waiting a day or two until the current cycle has finished. But you should also know that, depending on their severity, many injuries and health issues require several healing crises in order to reach full healing – and this would require you to extend the fast considerably longer. Whether it’s worth extending your current fast, or whether you want to pick up where you left off on a later fast is your choice!

      All the best,

    • Alison says

      Hello, I’m on day 11 of a 21 day fast, and my ketones today were 300 mg/dl (16.6 mmol/l), which seems high. But my glucose is hanging out in the 80-95 range. I had the crisis on day 6 (holy crow) but now I feel great and alert albeit weak. Should I worry about those high ketones? I’m not ready to stop.

      • Tallis Barker, D.Phil. says

        Hi Alison,
        Thanks for sharing. Those are pretty high ketone levels. Most people stabilise at about 5-6+ mmol/l – so you’re well above that. Are you sure you’re getting accurate readings? If you feel great, there can’t be too much going wrong (weakness is normal), but it might be a good idea to get a reading from an alternative device.
        All the best,

  5. Den says

    Have you had success healing Crohn’s disease?

    • Tallis Barker, D.Phil. says

      Hi Den,
      Yes, with proper planning, zero-calorie water fasting heals all digestive issues – including Crohn’s.

  6. Austin says

    Hey, I am doing a 30-40 day water fast. Is consuming lemon water with the lemon seeds going to negate the fast? Or will I still experience deep healing? I have a feeling the lemon and lemon seeds will only improve the quality of healing.

    • Tallis Barker, D.Phil. says

      Hi Austin,
      It all boils down to calories. I assume by ‘lemon water’ you’re not referring to lemonade :-).
      About the lemon seeds: I’m doubtful about their improving the quality of healing. They only give your digestive system something to think about, and as you get further into the fast, this is going to increase the likelihood of acid reflux. More importantly, if you want to get toxins OUT of your system, it’s best not to put anything INTO it – or to put it more technically: anabolic and catabolic states are mutually exclusive. (This applies to both the lemon water and the seeds.)
      Hope this helps,

  7. Denise says

    Hello! I am currently doing a water fast to detox and heal my body. I am overweight so is it safe for me to prolong the fast past 10-14 safely? I do not work outside the home. I do walk and do Pilates for exercise. I have been gentle with the Pilates and walking. Not pushing any of it. Just moving and stretching my body.
    Also how would I know if my body is ready for me to stop fasting. How long do you usually recommend someone fast if they are working on healing their body. I don’t want to stop too soon.
    Thank you!

    • Tallis Barker, D.Phil. says

      Hi Denise,
      Thanks for writing. These are important and complex questions! First, assuming that you’ve followed all the advice here on this website, it’s almost certainly safe for you to safely extend beyond 10-14 days. It’s really only once you’re well past 21 days that more serious issues might arise – and even here this occurs only rarely. It’s a question of learning to read the signs and symptoms that your body might want you to stop fasting, but, again, I very rarely see this among my clients. It’s almost always the mind which demands an end to the fast before the body!
      In terms of how long to fast in order to heal, there’s no easy answer. It will depend on the particular type of issue, the severity of the issue, as well as the strength of your immune system and the toxic load already carried by your body at the beginning of the fast.
      Hope this helps,

  8. jason says

    I must work a physically demanding job. Any insight on 14 to 21 day fast and so.e heavy lifting. On feet all day. Breaking a sweat. Thank you for your work

    • Tallis Barker, D.Phil. says

      Hi Jason,

      Thanks for sharing. I think you’ll find it pretty tough – if not impossible – to carry out an extended fast while doing a demanding physical job. The problem is that your body will be running on the fuel provided by fatty acids, which requires a 100% aerobic burn (metabolism which creates energy through burning oxygen). Unlike carbs, which can be burnt in either an aerobic or anaerobic environment, this means that any activity which would normally get you into so-called ‘oxygen debt’ is going to be impossible.

      In everyday life, the experience of oxygen debt involves heavy breathing after completing an activity, in order to re-oxygenate the blood. (More technically, you’re breathing heavily after the activity in order to return the build-up of lactic acid back into pyruvic acid.) If you’re breaking a sweat doing your current job, there’s no question in my mind that you’re running into oxygen debt.

      In contrast, the 100% aerobic burn of ketosis means that you can burn only what you’re able to provide oxygen for in real time. This is the level of activity normally associated with walking or low-stress activities. I’m afraid that’s going to limit what you can do while working.

      Hope this helps,

      • jason says

        perfect response. Thank you!
        Today is day 4 of the water fast. I hired a helper to do the heavy lifting and was able to not have heavy breathing or break a sweat at all. I really took it easy at work. I think I will stop at 7 days because next weeks work will be harder.
        I plan to stop this work and transition to working from home from the computer. Maybe then I will aim for a longer healing fast when I can rest and meditate and light stretching.
        I will seek your advice and possibly coaching when that time comes.
        thanks again for taking the time to respond so thoroughly.

        • Tallis Barker, D.Phil. says

          Glad things have worked out for you like this! It’s definitely a good idea to stop at 7 days if next week will be more demanding. These 7 days won’t have been wasted, though, even if originally you’d hoped for a longer fast. It means your body will be able to dive in quicker next time to do some intensive cleansing – and you’ve already made a good start on the detox this time around anyway.

  9. Cindy Fritz says

    Your article was very interesting and informative. My question is, I have heard of juice fasting which still has calories so I am not much interested in that but what happens if you drink non caloric drinks like broths or diet soda? Will healing still occur with those items entering my body? I was dx with DM ll recently and would like to work on that. Thanks

    • Tallis Barker, D.Phil. says

      Hi Cindy,

      Glad you enjoyed the article. If you’re fasting in order to heal and cleanse, then there’s no question that the best thing for you is a water-only fast. Broths do have calories, albeit minimal, which will lower the efficacy of the fast to a degree. They can also contain salt, which will work against the anti-inflammatory effects of a water-only fast. The problem with diet sodas is that they’re often highly acidic, and this compounds the build-up of acids which already takes place through cleansing. This is likely to exacerbate detox symptoms. On top of that, the bubbles in soda (in addition to being acidic) often end up over-stimulating the stomach, which leads to the production of stomach acid and reflux.

      If water feels too ‘boring’, you might consider adding occasional non-caffeinated herbal teas instead. These don’t adversely impact on the efficacy of a healing fast.

      Hope this helps,

  10. Greg Simmons says

    Thank you so much for all your help on this site!
    My question is this, I have been doing the Atkins diet (exclusively the induction phase of the diet) off and on for 24 years and I would like to know if I can break my 14 day fast with some creamy scrambled eggs? I would like to stay away from all carbohydrates if I can, so I can continue my ketosis after my fast is over. I have lost 20 lbs so far on this fast, but I really need to loose another 30 lbs, at least.This is my third water only fast in the last year, (3, 5 , and now 14 day fasts) today I am on day 10. I value your opinion in this matter…
    Thanks again for all your help!

    • Tallis Barker, D.Phil. says

      Hi Greg,
      Thanks for your question. It’s never a good idea to break an extended fast on animal protein! Too many digestive enzymes are required after your digestion has been in hibernation for so long. You might get away with it, but more likely it will sit in your stomach as you struggle to digest it.
      It’s much better to focus on fruits and vegetables at the beginning of any refeeding process, regardless of what diet you plan on ending up on. You don’t need to worry about getting temporarily out of ketosis because you’re already fat-adapted from being on Atkins – and especially from having fasted for two weeks!
      All the best,

  11. Katina Sanders says

    Well I was pushing for 40 days but my ND felt I needed to start back with receding due to my intense fatigue along with MS diagnosis. I feel a lot better on my plant based diet, getting used to new things this year.

  12. Katina Sanders says

    Dr. Tallis,

    Thanks for all the information provided on fasting. It gives me great hope as I continue my 40 day fast. I have undergone one week already and feel confident as I read these inspiring posts. God bless you

    • Tallis Barker, D.Phil. says

      All best wishes to you, Katina, as you continue your journey towards greater health!

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