The 7-10 day water fast

Assuming you don’t have any urgent health issues which require an immediate extended fast (typically lasting 14-40 days), then I believe the best way to establish a long-term relationship with water fasting is to develop and nurture that relationship gradually. The most reliable way to do this is to work initially with short fasts which feel relatively manageable, without putting undue pressure on yourself.

After you feel comfortable with 3 day water fasts and, physically, your body can make the switch to ketosis without much fuss, 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 start to 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 might 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.

What happens during a 7-10 day water fast?

Despite some natural doubts and fears, many of my clients find that 7-10 day fasts tend to go more smoothly than they first expect (so long as they’re basically 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 – and during which your fuel tanks are also running on empty. From the third day on, though, ketosis continues to become increasingly efficient, and this typically leads to one of two outcomes.

On the one hand, some people begin to feel lighter and fuller with energy. In many ways, the fast can feel 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.

On the other hand, some people experience a distinct roller coaster ride from this point as detox symptoms ebb and flow. In essence, with your ketosis engine having powered up over the first three days, your body now wants to turn all of that energy towards detox and healing, which can actually lead to lower perceived energy levels. It’s important to remember that you’re not actually lacking in overall energy, but rather that energy wants to flow inwards instead of outwards like it does in everyday life. Don’t get disheartened: as hard as it often is, this means your body is working for you!

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 subside significantly after this point, assuming you’re able to rest and not overextend yourself with too much work. One of the most frequent conversations I have with clients is the need to try and slow down the pace of everyday life, both in order to maximise healing as well as to minimise any remaining hunger pangs. This doesn’t necessarily mean you need to give up your job and spend the whole day in bed (!), but it does mean that it’s a good idea to try and reduce your commitments during the fast. Remember: your fast should be about you and not trying to pretend it’s ‘just another day’ of your regular routine.

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. This is important for two reasons. First, 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. (continued below)

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Second, during the most intense periods of detox, your liver is often forced to release semi-processed toxins into the bile, which then leads to a potential toxic build-up in the colon. You don’t want to complicate matters further by having any digestive remnants hanging around as well!

The transition out of a 7-10 day fast is equally important because 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 can rot, so a similar situation can occur now too. Anything other than juices or the simplest fruits and vegetables is likely to sit in your stomach, until your digestive system is able to cope. This can and will take days. After fasting, many of my clients find that the transition time back to normal eating with a normal appetite can last up to a similar length of time as 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 follow 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:

Days 4-6 is the usual timeframe when your body reaches maximum ketosis. This is clearly supported by my clients who love data, and who choose to measure their daily blood ketone levels. With a remarkable degree of consistency, most of them reach an average maximum ketosis of 5-6 mmol/l, usually around Day 5 (+/- 1 day).

At this point, after having fully ramped up ketosis, your body will want to devote greater resources to detox and healing. You’ll know when this happens! Above and beyond the detox symptoms mentioned above, your breath will stink. Your sweat and general body odour will also 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 4 or 5 of my first 7-day water fast, when my tongue began to produce a foul metallic-tasting froth. It tasted literally like poison.

Beyond the possibility of nausea at any time, detox can also typically cause aches in the muscles, connective tissue and the lymphatic system. However, this is generally 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 usually no need to contemplate longer fasts unless you’d like to address a serious health issue or unless you feel the need to go deeper into your being spiritually. A weekly 24- or 36-hour fast (or perhaps 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, and let the fast come to you – rather than the other way around!


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. If you’ve heard of famine victims dying after eating too much, then this is the reason. Although after a 7-10 fast the danger is more digestive than metabolic, the body cannot be rushed in this process.

If you have any doubts, I offer a downloadable 67-page PDF which covers refeeding for any length of fast.

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234 responses to “The 7-10 day water fast”

  1. Hi Tallis,
    Would you recommend this length of fasting (7-10 days, or longer) for someone who is underweight?
    My BMI is 18.4 and based on my own rough estimation, my body fat is 5-7%. 35 year old male. I have been 5’5/110lbs since I was 15-16 years old.
    I have sever digestive issues (IBS-M, acid reflux, and bile acid malabsorption) that I would like to heal as I have read anecdotal evidence of many people who finally became symptom free after an extended water fast. I don’t have any other health issues (that I am aware of).
    If extended fasts are not recommended, would 3-5 days be okay?

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

      Hi Eddie,
      Thanks for sharing. I’m afraid I can’t recommend any specific pre-planned length of fasting for you. More important than this for someone with a very low BMI is to determine the length of the fast based on your evolving weight while actually fasting. One thing is for sure: you’ll need to work with short fasts until the fasting heals your digestion to the extent that you start to put on more weight, which will enable you to contemplate longer fasts. The exact parameters of this plan, however, are something which I could only discuss with you one on one, depending on all the other details in your health history.
      Hope this helps,

      1. Thank you for your reply Tallis!
        I will experiment with shorter fasts (starting with 36h, going to a max of 72h) for one month (or longer), on a weekly basis. Hopefully I will see some improvement that would encourage me to then do at least a 7 day fast, for which I will reach out to you for 1:1 coaching/guidance.

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

          HI again Eddie,
          You’re welcome! That basically sounds like a good plan – but I’d also include one important caveat. It’s important that in approaching 72-hour fasts you don’t follow up with any subsequent fasts until you’ve at least regained your starting weight. Hopefully this happens within a few days, but you have to listen to your body here and take additional time if necessary.
          All the best,

          1. Hi Tallis,
            That’s great advice. I will be monitoring my weight.
            Thank you once again.

  2. You mention prepping for a fast longer than 3 days to avoid food rotting in your intestines. Where can this info be found? Which ebook that you have available, if any, or somewhere on this site? I looked around and didn’t find anything further about this. Thanks.

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

      Hi Steve,
      Thanks for writing. I’m not quite sure which info you meant: is it about how to do a dietary prep in order to avoid negative digestive repercussions during the fast? I don’t have any material specific to this issue, but in principle it’s largely the opposite sequence of what happens at the end of a fast, going into refeeding. My pdf on refeeding includes tables/plans for all lengths of fasts, and you can use this as a guide (in reverse) for before a fast. Here is a link to the shop:
      All the best,

  3. Hi Tallis!

    Thank you for sharing all this wonderful information. I have done several 3 to 5 days fasts this summer, and I just completed a 10-day fast. Towards the end I developed acne around the bottom of my mouth, perioral dermititis. I usually have perfect skin and don’t have any acne. These ones are like a cluster and very deep under the skin, they look bumpy and red. I also had them when I did a 20 day fast a few years ago. I have done refeeding and hoping that when I turn to normal eating they will be gone. Do you have any idea why that might be happenning? I’d love to hear your insight.

    Thank you!


    1. Tallis Barker, D.Phil. Avatar
      Tallis Barker, D.Phil.

      Hi Anabel,
      Glad you’ve found the website useful! To answer your question: skin issues often do erupt while fasting. The exact cause is hard to say without having worked together through your fast, but most likely it developed following a period of more intense detox, in which your liver as the primary organ of detox was unable to fully manage the breakdown of toxins in real time. In most cases, this kind of issue should resolve in time, but it’s also true that sometimes rashes and ‘angry’ skin will linger after a fast if not managed properly. Based on your previous experience, though, it sounds like yours will probably resolve by itself.
      All the best,

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