The 7-10 day water fast

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After you feel comfortable with 3 day water fasts and your body can make the switch to ketosis without much fuss (more info here), then it’s time to consider the 7-10 day water fast. For it’s only after you begin drawing solely on the energy of fat cells that the process of detoxification can kick into a higher gear (more info here) and you can reap the greatest benefits of a water fast. This means that a 3 day fast simply isn’t enough to confront any deeper issues you want to heal.

If you’ve found it difficult to get through your first few three-day water fasts, it’s only understandable that the thought of a 7-10 day fast seems even more daunting. For this reason, I offer private online consultations and coaching for water fasting. Alternatively – and even better for getting the deepest experience out of your fast – is to attend a fasting retreat.

What happens during a 7-10 day water fast?

Despite any doubts and fears emotionally, physically 7-10 day fasts tend to go more smoothly than you might first expect (so long as you’re healthy and don’t have any serious issues with detox). This is because your body does the hardest work in the first three days while it establishes ketosis – during which your fuel tanks are also running on empty. From the third day on, ketosis continues to become increasingly efficient, and so you’ll begin to feel lighter and fuller with energy. Increasingly, the fast feels like a celebration of freedom from the daily need to eat food. This freedom, as well as a lighter body and clearer consciousness, can feel so good that many people actually experience a sense of reluctance in returning to food at the end of the fast. There really is a beautiful purity about just being, without the needs and addictions of food distracting you, weighing you down.

As your healing metabolism firmly establishes itself by the end of the third day, the digestive system is in the midst of shutting down its normal function. As a result, most hunger pangs usually (but not always) subside significantly after this point. Given that digestion comes to a halt, it’s also extremely important to consider how and what you eat in the transition period both before and after any fast longer than three days. The transition into a fast is important because you don’t want your digestive system to shut down with food still remaining inside the intestines. It will rot inside you. Not a pretty thought. And as it rots, the toxic by-products aren’t going to help your body – precisely when you’re trying to detoxify. The transition out of a fast is important because (continued below)


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your digestive system is hibernating. It can’t digest. You have to wake it up slowly and with respect, eating small portions of easily digestible foods. Otherwise, you’ll be sorry! Just as any food remaining in the gut at the beginning of a longer fast will rot, so a similar situation can occur now too. Anything other than juices or the simplest fruits and vegetables will sit in your stomach, until your digestive system is able to cope. This can and will take days. After fasting, I find that the transition time back to normal eating with a normal appetite is similar in length to that of the fast itself.

I remember the exuberance of celebrating the end of my very first 7 day water fast by eating pizza. It weighed like an anchor in my stomach for literally days afterwards… Needless to say, I learned my lesson afterwards!

The 7-10 day water fast in greater detail:

Days 1-3:
Of course, the first three days of a 7-10 day water fast generally follows the process described in the three-day water fast. With experience, though, it will become much easier – even enjoyable – and the process to complete the switch to ketosis will accelerate.

Days 4-6:
After fully entering ketosis, your body can devote greater resources to healing and detox. You’ll know when this happens ;-). Your breath will stink. Your sweat and general body odour will stink, as your skin releases toxins which may have been locked up inside you for literally most of your life. No, it’s not a very social occupation! But directly experiencing the repulsive things coming out of your body can make you appreciate how good it is to be free of them! It will give you the willpower to continue fasting in the future, no matter how hard it may have been in the beginning. I myself became a convert to water fasting on day four / five of my first seven day water fast, when my tongue began to produce a foul metallic-tasting froth. It tasted literally like poison.

Detox can also make the kidneys and muscles ache, but generally this is much more bearable than during the first three days, when you’re lower on energy. You’ll probably find there are periods when physically you actually feel great, with a clear and still consciousness, and then this will pass into a period of deeper cleansing when you feel weaker and heavier. During longer fasts, things always change. From hour to hour. From day to day. There’s no apparent logic to it, so don’t try to analyse. Just trust your body and go with the flow. It knows what it’s doing: how and what to detox, where to heal, and when to take breaks in between these more intensive periods.

Days 7-10:
You might be wondering why I’ve not listed a ‘5 day water fast’ or something similar here on this website. If you’d like to try four or five days, then by all means do! Every day of fasting does you good! But it’s because of the benefits of what often happens around the end of the first week of fasting that, in my opinion, it’s worth aiming for a period of 7-10 days. It’s at this point that you may experience a so-called ‘healing crisis‘. This occurs when your body has moved beyond the simple ‘house-cleaning’ of everyday toxins, and has started to tackle deeper illnesses, injuries and traumas (both physical and emotional). This is also described in the article on extended fasts.

What is a healing crisis?

A healing crisis consists of symptoms of an (old) illness returning or temporarily intensifying during the fast itself. This can be a little worrying, especially if you don’t understand what’s happening to you at the time. Nevertheless, it is perfectly normal. Think of it like this: fasting calls the illness forth from where it is otherwise locked physically into the depths of your body and/or emotionally into your subconscious. In calling it forth, you may temporarily experience the symptoms of the illness more acutely, but it is precisely through shaking it loose that you are then able to permanently expel the illness and truly heal. Western medicine can hardly ever achieve this to the same degree, because toxic (allopathic) drugs and physical procedures tend only to reduce or suppress symptoms. They do not deal with root causes of illness!

Occasionally, healing crises can be extremely intense. 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 fasting coach like myself can really help. If it’s a healing crisis, you should ideally try and push through. If it’s not, you should stop immediately!

What about water fasts longer than 7-10 days?

Given the degree of detox and depth of healing which occurs during a 7-10 day water fast, there’s no need to contemplate longer fasts unless you’d like to address a serious medical issue or unless you feel the need to go deeper into your being spiritually. A weekly 24- or 36-hour fast (or regular intermittent fasting instead) combined with an occasional 7-10 day fast should be all that’s necessary in order to preserve good health. Exactly how frequently you conduct a 7-10 day fast is up to you, but please don’t violate your body by fasting before it’s ready – even if your rational mind believes it’s for a good cause. Once you’ve faced and overcome the basic physical and emotional challenges on shorter 1-3 day water fasts, you can begin to trust your body and what it wants. At this point, your body always knows best. When the time is right, you’ll feel an inner urge welling up inside yourself to do a 7-10 day fast. You’ll look forward to it. For some people this may be only once every few years, for others up to a couple of times per year. Just follow your inner calling.


— A stronger immune system (click here)
— Deeper states of consciousness (click here)
— The deepest detox (click here)
— Extended healing fasts (click here)

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  1. What about a small amount of black coffee on a water fast? Just started a water fast and found your site, thank you for all of the great information.

    • Tallis Barker, D.Phil. says

      A small amount of black coffee isn’t going to make much difference on 24- or 36-hour fasts. For anything longer than that, it starts causing problems for most people. Acid reflux is much more likely. The acids in the coffee also tend to stimulate digestive juices and hunger (although over the first day or two the caffeine can initially reduce it). The caffeine also works against the healing potential of the fast, since this drug stimulates your body towards a faster metabolism – when precisely the opposite should be taking place. It also raises blood pressure, when precisely the opposite should be taking place in order to help the cells cleanse most efficiently.
      You get the idea 🙂

      • Pam says

        You are exactly right, as usual! I also heard black coffee was ok, but it made my last fast the worst experience. The reflux was horrific and the reason I stopped my fast after only 5 days. Also noticed my BP didn’t go down as usual. Never again; it’s water only from now on.

        • Tallis Barker, D.Phil. says

          Hi Pam,
          Sorry to hear about your own experience with black coffee. There really is a lot of unreliable information on the internet – some of it even published by doctors (one or two are quite well known…) who claim to know about fasting. What they don’t understand is that some of the principles which do work with intermittent fasting definitely do NOT work when applied to longer fasts!
          Yes, water only from now on 🙂

  2. Lisa Devroy says

    I just finished day three of water fast but apparently, I did not start this out right, I dove in after several indulgent days leading up to it. Is there any way to continue the fast and cleanse my body of the food that is probably “rotting“ in my body? Ewwww…
    Just an FYI I did a 14 day water fast several years ago… and it was an amazing experience. This is not my first one.

    • Tallis Barker, D.Phil. says

      Hi Lisa,
      Thanks for writing. A lot depends on you and your digestion. I once had a client who started a 40-day water fast after having had a steak (!), and they managed just fine. Of course, this is the exception and not the rule, but it all depends on how your body eliminates the food of those ‘indulgent days’ before your fast. One option would be to do an enema to flush out whatever remains. Another would be to continue and see where it takes you. There’s no clear-cut answer here!
      All the best,

  3. ginger boyd says

    Thank you for this article. I’ve done a couple of 7 day water fasts in the past mostly for spiritual reasons. Now i’d like to do it for healing. Have you ever heard of fasting for allergies? I just have been diagnosed with allergies and allergies induced Ashma. My first thought was that I need to fast!

    • Tallis Barker, D.Phil. says

      Hi Ginger,
      Thanks for your question. I’ve worked with numerous clients for whom healing allergies is either their primary or secondary goal. – And yes, fasting can be very effective in this respect! Although allergies will often temporarily improve during shorter fasts, you’d usually want to aim for around 21 days in order to start effecting permanent change. It may be worth looking at your post-fasting diet too. If that sounds too daunting to manage alone, you can find me on the coaching page :-).
      All the best,

  4. Mert Yilmaz says

    Hello Tallis,

    I finished my 7 days water only fast. It felt good.

    Then I consumed: Orange and apple juice + 5 solid red apple.

    After 4 hours later I drunk tomatoe and vegetable soup (contains little bit oil and little bit salt)

    Will I die of refeeding syndrome?

    • Tallis Barker, D.Phil. says

      Hi Mert,
      Refeeding syndrome is really only a potential issue on longer fasts, usually from around 14+ days. Maybe you overdid it with the apples, but you’ll certainly survive! (And at least you focussed on fruits and vegetables, and not heavier food groups.)

  5. Belinda Palmer says

    Hello Dr. Barker,
    I’m interested in doing a 21-day water fast and wondered how you go about supporting me throughout. I’m not worried about the physical part of the fast but know that it quickly becomes a ‘mental’ game. I’ve fasted several times before – the longest being a 9-day water fast (with some light herbal teas and a little light black coffee) but 21 days is a bit daunting when one is alone.

    • Tallis Barker Ph.D. says

      Hi Belinda,

      You’re absolutely right: the challenge is 90% mental and 10% physical! Coaching works through daily video support calls and texting/emailing as necessary. All the information is found here:

      There’s a contact form at the bottom of this page if you’d like to pursue coaching further.
      All the best,

  6. Phil S says

    Hey Dr Barker, I’m thankful I found your site. I’ve got some health issues that I want to see if fasting will help expel. Well I jumped in with both feet and am on 5 1/2 days of a water fast. I was intermittent fasting before this and I’ve fasted for a couple days in a row in the past, but never beyond 2-3 days. I did ok for the 1st 3 days but day 4-5 I was pretty sluggish, tired, and my heart feels like it’s going to beat out of my chest. I couldn’t sleep last night due to muscle aches (felt like the flu), acid reflux, and I got sick. I was able to sleep for a couple hours this morning and feel a bit better – but wondering if I should quit and try again another time when I’ve had more ample time to prepare?

    • Tallis Barker Ph.D. says

      Hi Phil,
      Sounds like you’re experiencing the first wave of deeper detox caused by your fasting metabolism. This does take a few days to activate and is the reason that you’ve not felt these symptoms during your shorter fasts. I honestly can’t advise you what to do now without having worked together – I’d need to be familiar with your background plus the reasons that you’re fasting. You could almost certainly push through and keep going, but I can’t say whether this would be the most effective (or comfortable!) solution.
      All the best,

  7. M Lee says

    Hi Tallis, I attempted a water fast and made it to the morning of DAY 3. Early in that morning I felt like I had a slow heart beat and felt very tired. Is this normal? I’m wanting to start a water fast in 2 days, however, I’m nervous I’ll end up stopping it again. My goal is 7 days minimum and 21 days the most of my mind and body can! A little ambitious from just a full 2 day fast.

    • Tallis Barker Ph.D. says

      Hi M lee,
      Thanks for writing. Feeling tired is very normal for the first days into a water fast – and even longer if you don’t have any fasting experience. There’s a lot of detox to do! I can’t comment on your heartbeat without knowing more of the specifics of what had happened before then. The main thing is not to dive into anything too deep. Jumping straight up to 7-21 days is a big leap – which isn’t to say you can’t or shouldn’t do it. But do respect your body and mind along the way. Don’t force things, and if it doesn’t feel right, then stop. You can always pick things up with another fast, until things feel easier and more natural!
      All the best,

  8. Peter S says

    What you write really makes sense now, especially since the 7-day fast rash is around four of the lymph nodes. The body is wonderfully made! One could speculate that a person who has so much toxins expelled as to develop a bad rash really benefited from the fasting “housecleaning”. 14 days would have been even better but this was my first time and it was not easy. What would be a sensible amount of time to wait until fasting again?

    • Tallis Barker Ph.D. says

      Seven days is a really strong accomplishment for your first time – so I hope you feel good about that!
      In terms of the length of time before your next fast, think about it like this: if the human body is capable of doing a 40-day fast, then there’s no physical reason to wait at all after a 7-day fast. The issue is more psychological/emotional, and it’s extremely important to give yourself enough time so that you don’t go into the next fast meeting a lot of resistance from that part of you which felt deprived during the fast.
      We use food to distract us from boredom, to fill in the holes where we’re not feeling comforted or loved. It takes time and experience in fasting to clearly recognise this, and learn to free yourself from this. Until then, enjoy food in between your fasts so that when you fast, you can enjoy this too!

  9. Peter S says

    Fantastic site and information! I like it better than Dr Fung’s book which is very mainstream and geared to shorter fasts. I bought two of your ebooks and finished them in the same day. Great information. I felt hungry and tired the whole time, I honestly expected a smoother ride.

    I was planning a 10 day fast but today on my Day 7 of waterfasting I broke it because I have just developed what I believe are called “Keto Rashes” on both arms and legs. Not much itching but it is very red. I have never had anything like it. Tallis, is fasting-induced rashes something you have come across?

    • Tallis Barker Ph.D. says

      Hi Peter,

      Thanks for sharing. Jason Fung has done a lot of really great things for intermittent fasting, but, yes, when it comes to longer fasts I have to say that our approaches definitely differ…

      To answer your question: yes, I’ve come upon rashes quite frequently. The timing of your rash is very typical, and it’s something which can happen during or especially after a water fast. It can range from just a slight reddening of the skin to ‘prickly-heat’ looking red dots, and can be itchy or not. It usually lasts anything from a couple of days to a little over a week. It’s nothing to worry about, and, in my experience, is caused as a result of toxins passing through the skin, thereby irritating it. This also correlates with the greatest degree of ‘housecleaning’ during the first 7-10 days of a water fast.

      Based on what you described, the best thing you could have done was probably to continue your fast until the rash disappeared by itself. (To say anything more meaningful here, we’d have had to be working together through your fast.)

      The term ‘keto rash’ is a little confusing. If you Google the term, you’ll usually find something like: ‘researchers are still not entirely sure what causes a keto rash.’ In Western medicine, doctors all too often apply blanket labels to conditions about which they don’t fully understand, and which may or may not have different causes. (This holds especially true with autoimmune conditions, such as ‘Lupus’ and ‘ME’, to name just a couple.) In this particular case, doctors also have to admit that they don’t even know if ketosis causes a keto rash!

      Hope this helps,

  10. Lydia says

    I am using a breath ketone meter. When should I worry if my levels are too high? At first during my 14 d of a ketogenic diet, it ranged from 1.7 to 2.6. Now since I am doing water fasting, the levels have slowly risen to 4.4, 7.2, and 6.7. I would like to know when I should worry and at what level should I end my fast.

    • Tallis Barker Ph.D. says

      Hi Lydia,
      Thanks for sharing your concern. Fortunately, there’s no need for concern! During a water fast, your body will give you whatever rate of ketosis is right for you! This is going to be considerably higher than anything you’d experience on a keto diet, so don’t let any arbitrary ‘good’ or ‘bad’ numbers put you off. If anything, the higher the ketosis, the better in this context – so it sounds like you’re doing great!
      All the best,

      • Lydia says

        Thank you so much for your quick response. My numbers are staying high and the weight is coming off. While I’m fasting I am also reading about nutrition and have decided to become a Nutritarian. In this way I can begin to give my body what it needs to repair itself after the fast. I will also continue intermittent fasting as well as incorporating 2-3 day fasts monthly. Thanks so much for all your advice. I learned a lot from your fasting articles.

        • Tallis Barker Ph.D. says

          Glad to hear that you benefited from the articles on :-).
          Best of health to you!

  11. Shawn says

    I’d it safe to do a seven day water fast once a month ??

    • Tallis Barker Ph.D. says

      Hi Shawn,
      I’d say the question is why would you want to do a 7-day fast once a month?…
      And: are a series of 7-day fasts the most effective way to reach your goal?
      Context here is important.
      If you’re fasting to heal an illness, then the answer is definitely, yes, it’s almost certainly perfectly safe (assuming you eat an otherwise healthy diet). But in this case it often makes sense to try for a longer initial fast before backing this up with subsequent 7-day fasts.
      All the best,

  12. Lidia says

    Hi, thank you so much for all the information. I am wondering if herbal teas (caffeine free) are ok during water fasts? Thank you

    • Tallis Barker Ph.D. says

      Hi Lidia,
      Caffeine-free herbal teas are absolutely fine during a water fast in the sense that they won’t upset ketosis or cleansing. In fact, certain types of herbs can be used for their medicinal effect in promoting the cleansing of certain organs and body systems. The main reason to avoid herbal teas would be if you are more concerned with exploring the spiritual or psychological aspects of water fasting. In this case, removal of taste is powerful way to challenge yourself, especially when it takes place over a longer fast.
      Hope this helps,

      • Darryl J Elliott says

        very helpful

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