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. Jason says

    I completed a 3 day water fast a couple weeks ago and since then have been fasting over 20 hrs daily, a few times over 24 hrs. Been keeping my eating window 3 hrs or less many times just 30-45 minutes. I’m sure that doing daily fasts of 23 hrs and eating once are not as beneficial as a longer fast but just curious as to if keeping it a permanent routine would have incredible benefits.

    • Tallis Barker, D.Phil. says

      Hi Jason,
      Eating once a day (OMAD) can certainly have many benefits, especially in providing lots of rest for your digestion and allowing your body to do some good surface-level cleansing. Of course, longer fasts will go much deeper in terms of cleansing and healing, but that speaks for itself!
      I should also add that if you end up doing OMAD over the long term, it’s very important to make sure that your one meal truly provides you with a full day’s nutrition! It’s easy to get it wrong if you don’t pay enough attention to what you eat…
      All the best,

  2. Rachel says

    I just completed a 16 day water fast, and stopped because life events interfered and I really wasn’t feeling very good. Very lethargic and dizzy every time I stood up. Last year after eating a carnivore diet for only 5 weeks I was healed from chronic migraines and I cut my thyroid meds by 1/3rd. Now I’d like to get off of thyroid completely. Have you ever seen water fasting as a way to do that under the supervision of a doctor? I’m still eating grass fed beef, wild caught fish and pastured eggs for the most part and supplementing with a little iodine every day. Thank you!

    • Tallis Barker, D.Phil. says

      Hi Rachel,
      Thanks for sharing. First of all, congratulations on completing your fast. Yes, fasting can bring on a lot of detox symptoms – especially on your first few fasts – and if you’re also working this can be really tough! (It’s also not ideal if you’re fasting to address a health issue, because a lot of your energy gets consumed in work rather than healing!)
      To answer your question: yes, fasting can be used to get off thyroid meds completely. I’ve worked with numerous clients who have succeeded in doing so through an extended fast. If you need help yourself, feel free to reach me through the “coaching” page here:
      All the best,

  3. John says

    Does an extended fast heal trauma from sexual abuse?

    • Tallis Barker, D.Phil. says

      Hi John,
      Thanks for writing. Fasting CAN help to heal trauma, and I’ve worked with numerous clients for whom this was their main aim. However, an extended fast isn’t going to magically heal you by itself. It all depends on your approach to the fast, and I’d recommend working with an experienced fasting coach like myself as well as a therapist. It’s also going to be important to have a lot of time off from work through your fast, because the stress of a full-time job is going to cancel out the potential of a fast to help open you up and release the trauma.
      Hope this helps,

  4. Chris says

    Hi Dr. Barker, I’ve had endometriosis for the past 8 years and it’s been torture as far as pain levels go. Feels like my insides are being torn, twisted, burned and stabbed and it can last weeks at a time. This disease is hormone based (high estrogen). It grew on my ovaries when I was 40. I heard about water fasting and I have occasionally fasted for up to 46 hours (can’t seem to make it past that point) because I noticed that sometimes food will cause flare-ups in pain. Sometimes though, when fasting the pain goes up or doesn’t change. My doctor told me that because estrogen lives in fat cells, when losing weight estrogen is released and can cause flare-ups in pain while those fat cells are flushed out. Have you ever seen someone cured of this disease through fasting? If yes, how long does the fast have to be? Thanks!

    • Tallis Barker, D.Phil. says

      Hi Chris,

      Thanks for getting in contact. I’m sorry to hear about your pain levels. I’ve worked with clients suffering from endometriosis, and, in my experience, an extended fast is likely to heal or at least significantly improve your condition. The most effective approach would be to aim for at least 30 days. A lot depends on how severe the endometriosis is, and on how strong your immune system is. In order to maximise the efficacy of the fast, it would also make sense to include periods of dry fasting within the extended water fast. I know this probably sounds scary, and it’s something that I’d recommend doing only with coaching, but it isn’t something which has to push you beyond your comfort zone. If you need more support, I’m available for coaching here:

      All the best,

      • Chris says

        Thanks Tallis. I may try juice fasting first to ease into this because I know my liver is very toxic even though I don’t drink alcohol or caffeine. When I do a longer water fast, I will enlist your help.

        • Tallis Barker, D.Phil. says

          Hi again Chris,
          Setting things up first with juice fasting is a good idea, as it will initiate some good preliminary cleansing. This will allow you to go deeper more quickly when it comes time for your water fast.
          All the best,

  5. eric gilhouse says

    i am recovering from a partial knee replacment and want to start a long water fast but am unsure if it will be harmful to my healing process ?

    • Tallis Barker, D.Phil. says

      Hi Eric,
      Good question! Many people understandably assume that, because of the lack of nutritional intake, they won’t regenerate as quickly from surgery while fasting. In fact, the opposite is true. Last month, for example, I had a client who actually fractured her rib while on a 21-day water fast. The doctors told her it would take at least 6-8 weeks to recover, and that in any case she would need pain killers for a couple of weeks. Thanks to the body’s heightened healing metabolism while fasting, though, she actually recovered to the point of no pain at all (with no painkillers either) within 10 days.
      Trust your body – it knows best!

  6. meghan says


    I have been practicing the discipline of water fasting for two years now and am getting into more long term fasts.. My concern is this, Ive been told recently that long term fasting affects females sometimes negatively physiologically and that males dont necessarily have those risks? Mainly that we have a cycle and that fasting through that can create more risks than benefit? what is your opinion on female health and long term fasts ( more than 7 days?) thank you so much totally enjoy your site!


    • Tallis Barker, D.Phil. says

      Hi Meghan,

      Thanks for writing – and thanks for asking specifically about this question. The idea that fasting adversely affects women’s menstrual cycle and hormones is unfortunately another misguided judgement about fasting, based on incomplete knowledge. This isn’t just my opinion – this is a factual observation based on working with hundreds of women over the years.

      Yes, it’s true that an extended fast can disrupt a woman’s menstrual cycle during the actual duration of the fast itself. I’d say that, on average, about 50% of women doing fasts of 7 days or longer experience either a skipped period or a change to the timing and intensity of their period. Generally speaking, women who have regular cycles experience the least change.

      Women who already have irregular cycles tend to experience the most disruption during the fast (both for better and for worse), but they almost always find that afterwards their period is healthier and more regular – and that it often times more closely with the cycle of the moon. In other words, an extended fast can smooth out irregularities in the menstrual cycle. This is all part of the overall hormonal reset which takes place during an extended fast. When it comes to specifically women’s health, the same applies to those who are in their menopause. Many such women experience that the fast alleviates uncomfortable symptoms such as hot flashes.

      Hope this helps to dispel the misinformation!

  7. Clare says

    Hi! Enjoyed your site! I have a question, so difficult to find an answer anywhere. How long after a 40 day fast and refeeding can I start another one? I did 27 days in April, one week in May and am in a 50 day fast now. I do water/herb tea, supplements, salt and some nutritional yeast and a multivitamin. I do strict keto between fasts. thank you!

    • Tallis Barker, D.Phil. says

      Hi Clare,

      Good question! If you’re totally healthy, then after an extended fast lasting ‘x’ days, you can probably manage another fast after ‘x’ days of refeeding, without running into nutritional difficulties sooner or later. But a safer rule of thumb would be to assume you can do another fast after ‘2x’ days of refeeding. A blood test can also help confirm whether or not you’re ready to fast.

      Unless you have a special reason to include supplements, salt, nutritional yeast and multivitamins, I would avoid them, because anything going into the body during a fast slows down the process of toxins leaving the body. I’ve seen this time and again among my fasting clients!

      All the best,

  8. Daniel says

    Hey I’ve been constipated ever since I can remember the only was I can have a bowel movement is with coffee other wise I’ll go like every 5 to 6day and it will feel incomplete you think if I gas for 21 to 30 day it might help?

    • Tallis Barker, D.Phil. says

      Hi Daniel,
      Thanks for writing. There’s no question that many people find that an extended fast solves their long-standing issues with constipation. In this case, it’s very important to make sure you follow a high-hydration, high-fibre diet throughout the refeeding process, and to make sure that your diet is similarly working for you afterwards. You should definitely avoid coffee or other laxatives during the post-fast period. Unless there are other health issues going on which you haven’t mentioned (or don’t know about), I suspect you could fast for a shorter period than 21-30 days and still see a significant improvement.
      All the best,

      • Dan says

        But it’s better if I empty the colon because I fasted for a week before and if I don’t empty colon i will be bloated for the whole fast period what would you suggest enemas ?

        • Tallis Barker, D.Phil. says

          If you need an enema at the beginning of the fast because of chronic constipation, that makes sense (do it on Day 1). After the fast, you should avoid artificial interventions towards stimulating a bowel movement, and instead rely on a healthy refeeding protocol. Otherwise your body won’t learn how to accomplish this on its own.

  9. Ben says

    Hi i suffer from strabismus on left eye , could a 30 day water fast heal my nerves?

    • Tallis Barker, D.Phil. says

      Hi Ben,
      Thanks for writing. The honest answer is: I don’t know. I’ve never worked with a client to address this issue. If the strabismus is caused by muscle problems, then I doubt a fast would help in this particular case, as there isn’t a concrete ‘injury’ or damage to heal. If it is caused by neural issues, then there is a chance that the fast could improve things – but this is only a chance. Extended fasting does impact on both the peripheral and central nervous systems, but I wouldn’t want to speculate on the degree to which it might help you. One thing is for certain: it does take time for a fast to elicit neural healing, so your idea of aiming for 30 days would make sense. But that’s a big investment to commit to without any guarantees of improvement.
      Hope this helps,

  10. Ela says

    Hello 👋 I’m Ela. I have found your website very helpful. Thank you for this information! Im currently on day 6 of my fast which is the longest I’ve ever gone. The most I’ve ever fasted has been 3-4 days. I’m a small petit woman with a very high metabolism. I’ve been small my whole life. The main reason I started this longer fast is because I’ve been dealing with continuous cold sore outbreaks that my medication is not controlling anymore. I know this is because I’m very stressed and there are unfortunately many different things that I am dealing with from child traumas, to my current financial situation, to my current relationship, and even my view of the world and the people in it is very depressing. So also dealing with some depression/occasional suicidal thoughts. I noticed my cold sore flare ups has been going on for about 2 years which correlates with the amount of stress I have been experiencing. I know that stress is the number one cause that triggers the cold sore virus so I’m wondering if me fasting will even do me any good. I am aiming for 14 days but I’m not sure if my body can handle that. I’ve already lost a noticeable amount of weight and I feel very weak with heart palpitations everyday and as I mentioned it’s day 6 and I haven’t noticed a spike in my energy,only continuous weakness. I don’t feel any hunger pains though, and mentally I have accepted that I don’t need to eat and have committed myself to this fast. I am working on trying to release the severe negative emotions and traumas inside me. I was wondering if u had any experiences specifically about anyone ridding themselves of the cold sore virus with fasting.

    • Tallis Barker, D.Phil. says

      Hi Ela,
      Thanks for sharing. Yes, fasting boosts the immune system so it can fight off chronic illness and infections caused by viruses. Just in the last few months I’ve worked successfully with clients to heal from both Long Covid and HSV-2. I’ve not had any clients who have fasted specifically to heal from cold sores, which are caused by HSV-1, but I see no reason why you shouldn’t succeed. In order to do so, though, it’s likely that you’ll have to fast for at least 21 days. In order to boost the efficacy of the fast, I usually work together with clients to include periods of dry fasting within the extended water fast – but I definitely wouldn’t recommend this if you’re fasting on your own. Other factors which influence how long you’ll need to fast include (1) your pre-fast diet and underlying nutritional health as well as (2) your stress levels while fasting.
      If you need coaching, just reach out with the contact form on the coaching page.
      Hope this helps,

    • Roelf says

      Vitamin b12 helped me with allot of the same symptoms your having
      1000ug cyanacobalamin.
      1 a day for a month
      Then 2 once a week there after

      • Tallis Barker, D.Phil. says

        Hi Roelf,
        Thanks for sharing. Glad that Vitamin B12 helped you (if you can be sure that it was the B12). If so, it’s unlikely that your cold sore was caused by a virus but rather by a nutritional deficiency. Glad you were able to identify the issue!
        All the best,

  11. Bryan says

    How much time would you recommend to eat a healthy diet before beginning a fast? I’ve done multiple fasts in the past including two 20 days fast and a 7 day fast. However, I’ve been consuming a terrible diet for many months. I’d like to begin ASAP, but I also want to achieve maximum benefit. I’m planning to do a 25-40 day fast for vicious Lyme Disease (and other issues). I’d appreciate any feedback you can give. I will strongly consider hiring you as a coach if one of my stocks hit.

    • Tallis Barker, D.Phil. says

      Hi Bryan,

      There’s no single answer here. A lot depends on (1) your current diet and (2) the reasons why your fasting. In the case of Lyme Disease, you could argue that it would be worth spending a few months on a plant-based alkaline diet – but on the other hand you’d need to balance this against the time that you’d lose in hitting the disease head-on through the fast. In my view, it boils down to how long ago you contracted Lyme, how severe it was/is, and how ‘bad’ your current diet is.

      If we were to work together, I would also encourage you to include periods of dry fasting within the extended water fast, as this would help strengthen your immune system in its fight against the pathogen. It also applies direct pressure against the bacteria which cause the disease. It’s a technique I’ve applied successfully with numerous other clients, especially against Coronavirus and HSV. However, this technique isn’t something I’d recommend you try on your own!

      Hope this helps,

  12. Jackson says

    I have what i believe to be a hernia in my large intestine at the first part of transverse colon, it has caused a blockage and i get no urge to go to bathroom now. Have to force a movement, even an enema doesnt stimulate peristalsis. On day 2 of a fast to try and heal this. Kind of at my last resort here, any advice would be much appreciated.
    I don’t have a lot of weight to loose so i’m just going to rest in bed.

    • Tallis Barker Ph.D. says

      Hi Jackson,
      Thanks for sharing. A hernia is a physical/structural issue, and, as such, a fast isn’t going to be able to directly ‘undo’ it. There’s a possibility that having no food in your gut will allow the intestine to recede from hole in the abdominal muscle, due to lower pressure from within the abdomen. But I honestly don’t think a fast will have much effect on stitching together the hole: this isn’t the kind of healing that fasting is likely to catalyse. I hope you’ve seen a doctor about this!
      All the best,

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