Water Fast Coaching and Articles

Dr. Tallis Barker, D.Phil., Nat.Dip., NA.Dip., Naturopathic Water Fasting Consultant & Coach

14–40 Day Water Fasts: Healing Power, Benefits & Risks

Why would anyone fast for two weeks—or more?
For those seeking the deepest levels of physical, emotional, or spiritual healing, a 14–40 day water fast may offer what shorter fasts cannot. Once your body has fully adapted to ketosis, longer fasts allow for profound detoxification, immune recalibration, trauma release, and sometimes even the reversal of chronic illness. However, they also require care, preparation, and guidance.

In this article, you’ll learn what happens in extended fasts, how to prepare and refeed, and how to distinguish between a true healing crisis and signs that it’s time to stop.

Note: Extended water fasts of 14–40 days are powerful but demanding. They should never be undertaken without expert supervision, especially if you have chronic health issues, take medications, or are unsure of your body’s limits. Always consult your doctor before beginning any prolonged fast. This article is for educational purposes only and does not replace medical advice or personalised coaching.

To address chronic illness, deep trauma, or long-standing toxic load—levels that shorter fasts usually can’t reach.

Yes—if done without guidance. Extended fasts can deplete fat, protein, or electrolytes if pushed too far.

A temporary flare-up of past symptoms as the body clears deeply stored illness. It can be intense but is often part of the healing.

If true hunger returns, or signs point to electrolyte imbalance, it’s time to break the fast safely.

Very slowly and intentionally, with light plant foods. The longer the fast, the longer the refeeding process should take.

CONTENTS:

  • Introduction
    Why extended fasts are rare—but sometimes necessary—and what makes them so powerful.
  • Benefits of Extended Water Fasts (14–40 Days)
    How deeper fasting supports chronic illness reversal, detox, and complete healing.
  • Physical, Emotional, Spiritual Healing
    What happens beyond the body: trauma release, ego dissolution, and ancient fasting traditions.
  • Experiencing a Healing Crisis
    When old symptoms reappear—and how to know whether to continue or stop.
  • The Dangers of Fasting Too Long
    Understanding the risks: fat/protein depletion, electrolyte imbalance, and misreading hunger signals.
  • Refeeding After an Extended Fast
    How to break a long fast with safety and care—and why this step is just as important as the fast itself.

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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 3-day or 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 most modern medical doctors may tell you, conditions as wide and varied as Long Covid, gut issues (such as IBS, ulcerative colitis and food intolerances) adrenal issues (CFS/ME), diabetes, chronic high blood pressure, autoimmune disorders (including allergies and asthma), as well as certain types of tumors are all potentially curable. I know this for a fact, because I have personally worked with clients suffering from ALL the health issues listed above to the point of a full healing.

As a water fasting coach, I’m privileged to witness this miraculous healing potential of the human body every day! It does take time, though, and in order to heal effectively from chronic illness, the length of the fast must typically last 14-40 days.

In helping clients decide how long to fast, three main factors come into play.

First is the overall symptom picture – that is, the sum total of active health issues, all of which constitute a toxic load contributing to illness. Although, for example, someone may wish to fast in order to heal Long Covid, further questioning almost invariably reveals other health issues in the background, both past and present. Whether presenting with symptoms of their own or whether entirely sub-clinical and ‘invisible’, these apparently secondary issues tell a story of how, over the years, a client has arrived at the present moment.

The second factor which suggests how long a client may need to fast is the strength of their immune system. The primary factors here are age, diet, stress and, in the case of chronic illness, how much the immune system has already been worn down in fighting a war of attrition.

The third factor concerns the degree of prior cleansing – and especially water fasting. Quite simply, the more you’ve already fasted, the more quickly and powerfully your body can mobilise your immune system for healing.

Physical, emotional, spiritual healing:

Beyond physical healing, the deepest emotional and spiritual cleansing can similarly take place only through the sheer length of an extended fast. In fact, what I’ve seen over many years of coaching is that in order to achieve the greatest physical healing, it’s also necessary to surrender emotionally and spiritually to the whole process. A big part of my job is to help facilitate that process.

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).

In other words, getting through a 14, 21 or 40-day fast is often a mind game more than anything.

Letting go of your fears about fasting is just the beginning. The process of surrender also eventually leads to the release of pent-up, self-destructive emotions and, for some people, a catharsis of trauma from the distant past. In doing so, you’ll free yourself: discovering a place of inner calm and spaciousness where you can finally breathe. This is a hugely important part of the healing process.

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

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 focussed on cleansing the toxins of everyday life (and especially so if you haven’t been fasting regularly).

For the deepest and most serious health issues, 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 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! (continues below)

Not every healing process 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 undertaking an extended fast with the help of an expert who understands the subtleties and symptomatology of 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.

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The dangers of fasting too long:

  • Depletion of fat (adipose tissue)
  • Depletion of protein (amino acids from muscle tissue)
  • Depletion of electrolytes

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, it’s also true that normal periods of hunger can develop during an extended fast. The urban myth out there on the internet – that hunger simply disappears on the third day – is a gross oversimplification of what actually happens. On longer fasts, it isn’t uncommon for my clients to believe that ‘true hunger has returned’, and that they should break their fasts. Usually (but not always), this phenomenon simply constitutes a totally normal physiological phase of the fast, or – even more likely – their digestive juices are being driven by an increasing emotional desire to eat. Without someone offering an objective mirror on the outside, it can be extremely difficult to distinguish between the different possible scenarios!

In addition, two other less obvious scenarios demand the end of a fast. The first possibility is that you run out of amino acids (derived from 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 by breaking down proteins in a process called gluconeogenesis (described in greater detail in my article on the 3-day fast). However, the actual danger of depleting amino acids before fat tissue is largely theoretical. I have never witnessed this happen myself, and it is only likely to arise on fasts longer than 40 days in the case of someone who is morbidly obese with severely atrophied muscle tissue.

The final possibility is certainly a real danger: the depletion of electrolytes (blood salts), especially potassium or sodium. Although unlikely, this process is potentially life-threatening! Understandably, many people decide to take electrolytes while fasting, precisely in order to avoid this scenario. If the sole reason for fasting is to lose weight, then by all means do so! However, if you are fasting because of a chronic health issue, it is critically important to understand that taking electrolytes during a water fast compromises both the deepest cleansing and healing – as I have observed clinically among clients who choose to fast using electrolyte supplementation. (I will delve into the physiology of this in a future article.) Although the danger of electrolyte imbalance usually increases from only about the 21-day mark, it is extremely important to respond to the first warning signs if and when they do arise. Unfortunately, this is difficult to the untrained eye, because the symptoms of potassium and sodium depletion overlap with other totally normal detox symptoms. The key is in understanding the context as well as the overall, underlying symptom picture.

Refeeding:

After you break an extended fast, it’s extremely important to follow a well structured meal plan. In an ideal world, this should be tailor-made to the individual person, based on prior nutritional reserves, any dietary sensitivities, as well as the given health issue for which someone has fasted. When this is not possible, a comprehensive pdf on refeeding can be found in the webshop here:

How to break a water fast?

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. If you have any doubts, I offer a downloadable 86-page PDF which covers refeeding for any length of fast.

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353 responses to “14–40 Day Water Fasts: Healing Power, Benefits & Risks”

  1. HI, 17 year long type 1 diabetic (LADA) now in stage 3b kidney disease. Do you recommend a 40-day fast? What, if any, results have you seen in a case like mine? Thank you.

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Snabs,
      Thanks for writing. Extended fasting can help both T1 diabetes and kidney disease, but these are both higher-risk illnesses from the perspective of fasting. It’s never going to be as reductive as saying: T1 + kidney disease = 40-day fast. We’d need to go into a lot more detail in a full consultation to figure out the safest way forward, depending on your experiences so far and the specifics of your case. Without knowing more, a 40-day fast could be the best thing for you or the absolute worst.

      If you’d like to take this further, you can reach me here:
      https://waterfasting.org/online-coaching-and-consultations-for-water-fasting/

      Hope this helps,
      Tallis

  2. Hello there!

    Would a salt water flush every day be beneficial or slow up the healing process from an extended water fast?

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Shanna,
      Thanks for writing. So often with a water fast less is more – and this is a good example. Over time, a daily salt water flush is going to start washing out electrolytes. The repeated, powerful stimulation of the enteric nervous system is also going to prevent you from calming down your whole nervous system, where the deepest healing can take place.
      Hope this helps,
      Tallis

  3. Hi, I am on day 5 of a water only fast, and it is my goal to go for 21 days. I have done other fasts in the past, but this will be my longest. I have had a constant headache for the past 3 days – any suggestions?

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Leah,
      Thanks for writing. When it comes to understanding detox symptoms – which gives the foundation for how to treat them – context is everything. Beyond the obvious possibility of caffeine withdrawal symptoms (if you were drinking coffee/tea before your fast), headaches are in any case one of the most common symptoms in the first few days of the fast. Questions which immediately come to mind include: whether this is your first extended fast, whether you have headaches in everyday life, whether you’ve been exposed to any viruses in the last few days, how much water you’ve been drinking, and what other detox symptoms you’ve noticed in parallel with the headache. One general thing you could try is just oxygenating the blood by going for a slow walk, but to apply more targeted approaches we’d need to talk more.
      Hope this helps,
      Tallis

  4. Hi I am on day 7 of salt, potassium and magnesium. I have read some of the comments that are saying there is no need for salt. Would it be disruptive to just drop the salt and keep going? what about the potassium and magnesium? thanks

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Angela,
      Thanks for writing. It’s not quite as simple to say that there’s no ‘need’ for salt. Salt does lower the degree of detox and healing, but not all people can manage an extended fast without sodium – especially in cases of chronic illness. Part of my job as a coach is to ascertain the situation, to ensure that a client can manage safely without salt in order to optimize detox and healing, but supplementing if symptoms of deficiency occur. In your case, having already started the fast with electrolytes, the situation is a bit more complicated. If you suddenly drop sodium at this point, your kidneys will continue to excrete for the next few days whatever excess they’ve been accustomed to excreting since the beginning of the fast. Exactly where this will leave your sodium reserves is hard to predict!
      Hope this helps,
      Tallis

  5. I’ve just begun an extended fast. I would like to reap as many benefits as possible. I’ve included some herbal tea, nothing added, in my fast. Will that interfere with any of the deeper healing, or is it okay?

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Cari,
      Thanks for writing, and I hope your extended fast is going well. Most non-caffeinated herbal teas are fine, and they shouldn’t interfere with any of the deeper healing.
      All the best,
      Tallis

  6. The longest I’ve done was 47 hours. I had a headache most of that time and couldn’t stop thinking about all the different food to eat. I want to do at least 14 days but 24 would be even better and the absolute best would be a solid 42 but I cannot even imagine that right now so I have to start small and at least START it first. Chronic pain from lumbar neuroforaminal stenosis, nicotine addiction and mental health are my biggest ailments at 44 years old. I’m 5’10”, 180lbs. (mostly fat) and won’t be using any medication. I’m using store-bought drinking water and absolutely nothing else. Planning to rest as completely as possible, outside of bathroom use and trying to get sun on my skin. Sponge baths only and no deodorant or cologne. Brushing teeth and tongue with only a wet toothbrush. Dizzyness means increase daily water intake. Excessive vomiting or diarrhea indicates stopping the fast. Did I miss anything?

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Doug,
      Thanks for sharing. If you’re having trouble with 48 hours, then you’re definitely doing the right thing by working incrementally, especially if you’re going it alone. Otherwise, I’ve also worked with numerous clients who have been able to jump from 24 hours straight up to 7 days with the support of full coaching…
      About dizzyness: there are several possible causes, including low blood sugar, low blood pressure and a natural response to increased blood toxicity. As with any detox symptom, a lot boils down to context in understanding which of these factors are most likely driving the dizzyness.
      Hope this helps,
      Tallis

  7. I’m on day 10 of a hopefully 21 day water fast and all is going well. I do have a question though. I am still experiencing gas and some sticky liquid waste. Is this just my fat metabolizing?

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Dan,
      Thanks for writing. Glad that all is going well! About gas and sticky liquid waste at this point, 10 days in: it could be a variety of things, but what it definitely won’t be is metabolised fat. You’re body is going to burn fat for fuel, and this leaves the simple end-products of CO2 and H20. Thus fat from adipose tissue cannot end up in the GI tract.
      Hope this helps,
      Tallis

  8. I’m entering a 40 day water fast tomorrow. I’m 42, work out 3-4x a week, fairly active with 4 young kids. I started by doing 2 days of smoothies, and 2 days of bone broth before entering the fast tomorrow. I plan to do the reverse when I break the fast.

    Is it ok to take Amino’s, creatine, and liquid minerals while on the water fast? I don’t have any known health issues but I want the maximum cleansing from this fast in addition to depleting fat stores.

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Michael,

      Thanks for writing. Glad to hear you undertook some kind of dietary preparation before your 40-day fast. But I’m also assuming that before the 2 days of smoothies you had lightened things up too, right? Just to let you know, you’ll certainly need much more than just a 4-day transition at the end of your fast!

      To answer your question I’m going to give you some homework instead. Take a look at the calories of amino acids and creatine per 100g… And consider this: amino acids are the building blocks of all lean protein. With this in mind, would it be okay to eat steak during your water fast…?

      Hope this helps,
      Tallis

  9. Hello. Thank you for the great resource. I’m on day 3 of a water only fast. I’ve just started to experience a slight burning or raw feeling in the top and back of throat, and it’s pretty painful particularly when drinking water after the first couple gulps. Should I be concerned? The only guidance I can find online is that it’s a sign to stop fasting. Thanks in advance.

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Josh,
      Thanks for writing. Not sure where you found the guidance about stopping the fast… There’s a lot of unreliable information out there which is also perpetuated by AI – which of course can only learn from the unreliable information already present on the internet in the first place! One thing is for sure. This specific symptom in this specific context is definitely NOT a reason to stop your fast. Hard to say what’s going on here without discussing it with you in more depth, but it’s most likely a virus you’ve picked up from somewhere!
      All the best,
      Tallis

      1. Hey Dr,

        Thanks for the reply. Yea I assumed that was poor advice and am currently on day 6. I had read that a sore throat indicated thyroid function was being down-regulated due to nutritional deficiency 🤷🏻. That being said, that is a symptom that I have experienced before during fasts, but it has decreased significantly at day 6. Cheers,
        Josh

        1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
          Dr. Tallis Barker, D.Phil., Nat.Dip.

          Hi again Josh,
          This is a perfect example of how coaching would have avoided this mix-up :-).
          What with the additional information you gave in your last comment about this being a recurring issue, along with the timeframe of it resolving, I would never have suggested that it’s a virus. It’s probably not thyroid-related either (because of the pain when swallowing/drinking). It’s almost certainly a lymphatic issue. The tonsils and adenoids are effectively extra large lymph nodes. When there’s a lot of toxicity building up in the lymphatic system, combined with lymphatic sluggishness, lymph nodes can get inflamed and sore – as you’ve been experiencing in the throat. Understanding exactly why is something which would require further discussion, because there’s probably a reason why you’re feeling your tonsils and lymph nodes in other areas of the body.
          Best,
          Tallis

      2. Hello again Dr,

        Speaking of viruses; Have you worked with men who have HPV? If so, perhaps I should consult with you. If you have, how long was the typical fasting protocol for success?

        Cheers,
        Josh

        1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
          Dr. Tallis Barker, D.Phil., Nat.Dip.

          Hi again Josh,
          I haven’t worked with any clients who have specifically mentioned HPV as their reason for fasting (although it’s highly likely that, indirectly, I’ve worked men who do have HPV). However, I’ve worked with numerous clients suffering from other chronic viruses such as HSV, Epstein-Barr and Sars-CoV-2 (esp. Long Covid). Without knowing more about the details of your case, a typical fasting protocol would probably need to be in the region of 21 days, and it would also be important to consider elements of dry fasting (not something I’d recommend you do alone) as well as diet, both before and after the fast.

          Very happy to set up a consultation. You can reach me via the coaching page here:
          https://waterfasting.org/online-coaching-and-consultations-for-water-fasting/

          Hope you had a good weekend,
          Tallis

  10. Thank you! I hope your answer to this question helps someone else avoid a potentially dangerous situation too. I’m postponing my fast until after the procedure

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      That’s definitely the right thing to do!
      Tallis

  11. Hello! I am starting a (hopefully) 21 day water fast, and scheduled it so that a colonoscopy occurs half way through, thinking that would be good timing because I would be completely “clean”. But I hadn’t considered the anesthesia. My first priority for the fast is spiritual, but my 2nd is deep healing. 1) is my assumption that I could skip the cleansing prep accurate, and 2) what effect will the anesthesia have on the efficacy of the fast from a healing perspective?

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi Dan,
      I’m really glad you decided to write and ask about this! Apologies, but it’s not your question I’m going to answer but rather approach the whole idea of doing a colonoscopy while fasting. Most colonoscopies take place under full sedation. You simply ‘go to sleep’ and wake up after the procedure in order to save you any discomfort.
      However, anaesthesia is something you must avoid at all costs when fasting! In the same way that any drug reacts differently when fasting (generally acting more powerfully on a fasting body), the same applies to the drugs used to sedate you. It’s unnecessarily dangerous to play Russian roulette here.
      Hope this helps,
      Tallis

      1. Anesthesia is absolutely not needed in the majority of colonoscopies. Apart from mild discomfort during insertion of the scope, they are not painful (even polyp removal is painless). Bonus: you can get right up after your procedure and drive yourself home—because you feel fine.

  12. fullymeticulous6a17eb41b5 Avatar
    fullymeticulous6a17eb41b5

    Hello! Thanks so much for your work. Fasted a few times in the past including 3 day dry fast. Embarking on a 14-30 day fast depending on my responses. Curious – I have RO water. Should I purchase spring water for the fast rather than adding Celtic sea salt to the RO water? Thanks!

    1. Dr. Tallis Barker, D.Phil., Nat.Dip. Avatar
      Dr. Tallis Barker, D.Phil., Nat.Dip.

      Hi,
      Thanks for writing. I have many clients who use reverse osmosis water, and it’s hardly ever a problem (assuming the underlying quality of the water isn’t too bad!). For the majority of people, there’s absolutely no need to add sodium to their RO water when fasting. Salt lowers the degree of detox and healing, and most clients should avoid it when fasting.
      All the best,
      Tallis

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