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. Kayla says

    Hi, I’m considering fasting for 40 days, but wonder if it’s safe at a moderate weight. I’m about 130 pounds and 5’3″ and don’t want to lose an excessive amount of weight.

    • Tallis Barker, D.Phil. says

      Hi Kayla,
      From a health perspective, your weight is perfectly safe for your height, and I would estimate that you’ll probably lose in the region of 20-25 pounds over the 40 days. 110lbs is thin (especially by today’s more obese standards than any other time in human history) – but it’s not emaciated. Assuming average build, someone of your height could actually go down to 90-95 lbs before you’d start running low on fat reserves.
      Hope this helps,

  2. Daniel Garrigan says

    What if BP decreases towards low BP readings during a prolonged fast ?

    • Tallis Barker, D.Phil. says

      Hi Daniel,
      This is good! Your blood pressure should decrease during a water fast in order to facilitate detox. (It’s also one reason to avoid electrolytes, which prevent this from happening.) If your blood pressure drops a lot, then just be careful about getting up too quickly, thereby causing light headedness. This is the worst that can happen to you.
      Late into a fast (usually after 21 days at the earliest), there can be issues with BP which illuminate potential problems with electrolytes, but I don’t want to go into this here, because it’s too easy for readers without professional fasting knowledge to misinterpret the data.
      Hope this helps,

      • Daniel says

        Thank you for your reply Tallis, much appreciated.
        Kind Regards, Daniel

  3. Joëlle says

    I’m on my 6th day of my 14 day water fast and hardly experiencing any negative symptoms at all except for horrible acid reflux. Any suggestions?

    • Tallis Barker, D.Phil. says

      Hi Joelle,

      Thanks for sharing. I’m afraid acid reflux is very common while water fasting, both among those who suffer from it in everyday life and those who don’t. There are multiple possible reasons for it (and it’s something that I often work with clients on solving!), but essentially there are two main causes: either (1) the stomach is being overly stimulated through exactly what / how / how much you’re drinking or (2) the cleansing of the fast is causing acidosis in the blood, and your body is trying to unload some of the acid by converting it to HCl in the stomach.

      Without writing a whole essay on the subject, the best thing to do for (1) is to reduce the quantity and frequency of your water. It’s a lot harder to deal with (2), because it’s driven by the very nature of the fast – ie cleansing inherently produces acidic byproducts. The first thing you might try is deep breathing, which helps to oxygenate the blood, thereby balancing pH. Other solutions are more invasive, and really depend on the individual case (which is why I’m not going to go into them here).

      This isn’t an easy issue to tackle, and the first thing is to identify which of the two causes applies in your case. Having said this, though, fasting is also a fantastic opportunity to resolve acid reflux in everyday life – as many of my clients have experienced after having worked on it through coaching.

      All the best,

  4. Clare says

    After 5 months of many extended water fasts (7-30 days each) I am now fat-adapted! I have experienced so much healing by combining prayer with fasting, it’s awesome! I alternate between LCHF and keto between fasts for refeeding, portion control and good nutrition. My question is, now what? Do I keep my protein and fat ratio the same or lower my fat intake? I still have over 100 pounds to lose. Thank you, your website and information is very helpful on an often confusing topic. As an example, there is a lot of info out there for getting fat-adapted, but very little on what to do afterwards! I thought if anyone would know, you would!

    • Tallis Barker, D.Phil. says

      Hi Clare,

      Thanks for writing. Hmm, ‘what now?’ Well, that depends on your goals. Being fat adapted through a ketogenic diet can help in the early days of fasting, but the fact is that if you practise fasting regularly, you’ll become fat-adapted anyway (as I suspect you did too). If you find that a keto diet helps you lose weight, then great, continue to stay the course. Just remember, though, that over the long term, most keto diets are linked with higher mortality. (A couple of recent studies linked non-vegan keto diets to a four-year loss of life expectancy.) So once you’ve lost the weight, I would think about focussing on long-term health, including an exercise program you enjoy and a healthy diet that you also enjoy!

      In other words, if you continue to fast, you’ll stay fat-adapted regardless of your diet.

      For me the main thing is not to hurry the process of weight loss. Big, quick weight loss often ends up rebounding on you afterwards, because you’ve pushed yourself too hard psychologically. It can also cause problems with the skin losing its elasticity. So just aim for a steady improvements. It’s like in the Aesop’s fable: the tortoise always beats the hare!

      Hope this helps,

      • Clare says

        Hi Tallis, I never lose weight on keto or LCHF, as i said those are only for refeeding between my extended water fasts. My question is do i now lower the amount of fat i eat between fasts, or keep it the same, between fasts. Ive lost 48# in 5 months, with 82 overall days of water fasting. Which is a normal amount to lose without problems. Since my body prefers fat over carbs for energy now, should i lower my fats or keep them the same? I would like to be able to lose weight while eating mindfully, and not just while fasting.

        • Tallis Barker, D.Phil. says

          Hi Clare,

          Being fat adapted doesn’t actually mean that your body prefers fat to carbs. Actually, we are all biologically hardwired to favour carbs over fat. Being fat-adapted simply means that your body is able to burn fat for energy more easily than someone who doesn’t regularly force themselves into deep ketosis, either through regular fasting or through a ketogenic diet.

          In terms of lowering fat content or keeping it the same, I don’t believe there is a one-size-fits-all approach here. No diet works best or all people at all times.

          When I’m coaching a client through an extended water fast, we always work on tuning into the body’s messages about diet after the fast. After about a week of fasting, your body will certainly give you clues about what you should be eating for the best nutrition, as well as offer signs about any potential nutritional deficits. It’s a question of reading the signs, distinguishing messages from the body versus those from the mind, and following through on this during refeeding and afterwards.

          All the best,

  5. Aaron Cyr says

    is it advisable to fast for 40 days without a fast coach?

    Also, I add ionic calcium, magnesium, sodium, potassium, and (a little but of) sulfate in my water supply. Do I need to worry about testing my blood (salts) after having fasted for 7-10 days?

    • Tallis Barker, D.Phil. says

      Hi Aaron,

      Thanks for writing.

      Is it ‘advisable’ to fast for 40 days without a fasting coach? Well, I suppose it depends what you mean by advisable! Most people, especially if they’re generally healthy, are physically capable of managing a 40-day fast by themselves. Where I can help best is in cases where someone suffers from a chronic illness and is generally less resilient than the average person. Certain detox symptoms can indicate either the positive benefits of cleansing or that the fast should be terminated in order to avoid danger. The average person doesn’t know how to distinguish one context from the other.

      Many people also benefit from the support of a fasting coach because 40 days is a long time without food! As much as the body may be able to manage perfectly fine, your mind and motivation are likely to reach breaking point some time during those 40 days. I see this very frequently, and a coach like myself can help keep you on track to achieve your goal.

      A coach can also help you to get the best out of your fast. For example, if you take all the electrolyte supplements you mentioned in your comment, you won’t enjoy the full cleansing benefits of the fast!!! Electrolytes are very popular these days for a variety of misguided reasons, but there is absolutely no reason to use them if you’ve prepared for your fast properly – and a 40-day fast DOES require a little preparation!

      If you’ve prepared for your fast properly, there’s also no reason to need a blood test so soon as 7-10 days into a fast. Most of my clients don’t require any blood test at all during a 40-day fast, although it is perfectly reasonable to ask for an electrolyte or metabolic panel from around 21 days if you’re worried. (Blood tests help the most for people who suffer from chronic digestive issues involving a problem with absorption or severe food intolerances.)

      All the best,

  6. Ebony says

    Hi Tallis,
    I received healing from painful ibs issues during my first extended fast of 21 days (8months ago). Although the results were great the process was rough on me and I became quite weak due to other medical issues going in my body or the medication for it at the time. I had vowed never to go beyond a 5 day fast again.
    I am now on day 11 of what of a 14 day fast. This fast has been so wonderful. I have continued strength training but at a lower level and walking throughout this fast. I have not had the weakness of the first fast but instead have times where I am filled with energy. I am trying to understand why this fast is so different than the last one. Why is that?

    • Tallis Barker, D.Phil. says

      Hi Ebony,
      Thanks for writing. I’m glad fasting is helping you heal from IBS.
      What you’ve experienced this time around shows how well the body learns from previous fasts: how to get into ketosis, how to cleanse. Also, the first couple of fasts tend to be the hardest because the body is dealing with the accumulation of a whole lifetime’s worth of toxins.
      It’s very common to have higher energy levels after your first couple of fasts, and often a single extended fast (like your 21-day fast) is enough to do the trick. I experienced the same myself many years ago. This doesn’t guarantee that from now on all fasts will go equally smoothly, but it is certainly a general trend.
      All the best,

      • Mert says

        Did she heal from IBS

        • Tallis Barker, D.Phil. says

          Hi Mert,
          I’m afraid I can’t answer that, because Ebony isn’t one of my clients!

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