Water Fast Coaching and Nutritional Therapy

Dr. Tallis Barker | Extended Water Fasting Specialist | Registered Nutritional Therapist | Associate Naturopath

7-10 Day Water Fasts: What to Expect Day by Day

Expert Water fasting coaching with Dr Tallis Barker? D.Phil, Nat.Dip

ARTICLE CONTENTS:

  • Introduction
  • Two different perspectives: modern medicine and traditional health systems
  • Safety considerations before a 7-10 day water fast
  • At a glance: what happens during a 7-10 day water fast
  • Common myths about fasting
  • ‘Detox symptoms’ versus ‘adverse events’
  • What to expect during a 7-10 day water fast
    • Days 1-3
    • Days 4-6
    • Days 6-7
    • Days 8-10
  • What is a ‘healing crisis’ in fasting terminology?
    • My story
  • How to prepare for a 7-10 day water fast
  • Breaking a 7-10 day water fast: refeeding and safety
  • What about water fasts longer than 7-10 days?
  • FAQs

If you’re new to fasting, I’d always suggest nurturing a sustainable, long-term relationship with this extraordinary practice if possible. This may mean simply taking your time, working with shorter fasts which feel relatively manageable, and gradually building up the length of your fasts without putting undue pressure on yourself. If a 3-day water fast is a potential starting point for unlocking your body’s fasting metabolism through the activation of ketosis, then a 7-10 day fast is about going much deeper — and, for some people, it’s all they ever undertake in order to promote their long-term health.

About the author: Dr Tallis Barker, D.Phil., NT.Dip., Nat.Dip., is a naturopathic water fasting consultant and nutritional therapist who has worked with over 1,000 clients internationally. His work includes individual fasting consultations, nutritional therapy and published case reports. His D.Phil. is an academic doctorate, not a medical qualification. Full biography here.

What does going ‘deeper’ actually mean?

The answer to this question depends on who you ask. This is a critical consideration, because, depending on the given perspective, it directly influences the content of this article. Modern medical research tends to investigate specific physiological processes and measurable outcomes. In other words, it focuses on individual ‘trees’ in the forest. Traditional health systems, by contrast, often use broader concepts such as ‘detoxification’, ‘cleansing’ and ‘healing’ to describe the overall experience of fasting. That is, they describe the ‘forest’ and not the individual trees.

When it comes to describing what ‘deeper’ means on a 7-10 day fast, modern medical science is limited due to the minimal research conducted over longer fasting periods. Studies have indeed demonstrated, for instance, that downregulated mTORC1 pathways and upregulated AMPK are associated with fasting metabolism.[1][2] But the articles in question concern shorter fasts and animal studies, respectively. A recent review study confirmed the paucity of both reliable and useful information regarding extended fasts, concluding that researchers still cannot firmly establish when and in which human tissues prolonged fasting increases autophagic activity.[3] Applying the standards of medical research will always be complicated here, given the literally dozens if not hundreds of enzymes, hormones, and other biochemical messengers involved in the actual lived experience of fasting.

In contrast, most traditional health systems don’t even try to prove a specific physiological mechanism. Nor do they establish that particular symptoms are caused by the elimination of accumulated toxins, or demonstrate that the symptoms themselves are beneficial. Rather, they would describe ‘deeper’ through the lived experience itself — focusing on possible ‘detox symptoms’, ‘healing crises’ and qualitative rather than quantitative change — without being able or even attempting to trace any of it back to specific biochemical markers. It brings to mind the naturopathic idea that biology is not just a science, but also an art with an unquantifiable ‘X-factor’: something which the naturopath Dr. Herbert Shelton acknowledges in the title of his book The Science and Fine Arts of Fasting.[4]

Clearly, both modern medicine as well as more traditional health systems have their own advantages, and I believe it makes sense to remain open to both approaches.

In describing 7-10 water fasts, I shall therefore involve:

  • Quantitative findings of modern medical research
  • Qualitative interpretations of traditional health systems
  • Clinical observations from having worked with over 1000 clients through their fasts. These observations offer practical insight into the range of experiences people report, but they should not be confused with findings from controlled clinical studies.
  • Personal experiences from my own personal fasting practice over the last two decades

Medical information: This article is educational and does not constitute individual medical advice. Extended water fasting involves potentially serious health risks and is not a substitute for appropriate medical treatment.

Especially for those with long-standing health issues, fasts of a week or more do constitute a medically significant intervention; they are not simply a longer version of intermittent fasting. Situations and conditions which require medical assessment before such an extended fast include diabetes (especially T1), kidney or cardiovascular disease, pregnancy, breastfeeding, eating disorders, frailty, low body weight and the use of prescription medication.

It is also important to be familiar with symptoms which require urgent medical assessment during the fast itself, such as persistent vomiting, fainting, confusion, chest pain or palpitations. Although these symptoms are rare in the general population, they can and do occur. Occasionally, I myself have had to call off a client’s fast even within the first 24 hours, because of such symptoms.

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Over the years, I’ve observed that the actual clinical experience of a 7-10 day fast can vary widely. Although a 3-day fast can seem incredibly long the first couple of times you do it — and especially if there are a lot of mind games going on — there just isn’t enough time for a huge variation of biological processes to develop. Most importantly, over the first three days glycogen stores become depleted, autophagy begins to upregulate and ketosis gradually kicks into gear. For most people, this simply means that their energy drops and they may or may not experience symptoms such as headache and nausea.

Given that a 7-10 day fast is significantly longer than a 3-day fast, the more protracted element of time inherently allows for a greater number of permutations of the fasting experience. Especially if you’ve approached water fasting gradually, starting with short fasts (perhaps 36 hours) and then stuck with 3-day fasts until they feel both physically and psychologically smooth, then the psychological ‘weight’ of a full week’s fasting may not feel so daunting.

However, there is always a level of unpredictability when undertaking a 7-10 day fast. Some clients find they pass smoothly with no symptoms at all, while others experience powerful waves of headache, body/muscle aches and nausea (which may include vomiting). Even when someone is accustomed to shorter fasts, an initial 7-day fast can trigger an onslaught of symptoms while the second can pass smoothly — or vice versa.

For those with longstanding health issues, new or worsening symptoms during a 7–10 day fast are particularly important to take seriously. They may indicate that continuing would be inappropriate or unsafe — and should not be interpreted as evidence that a longer fast would necessarily provide a positive outcome.

One thing is for certain. There are myths circulating on the internet which simply contradict the experience of many people — and when someone has had expectations of an easy ride, a bumpy road can easily feel disillusioning.

In my experience, the most commonly perpetuated half-truths are:

  • Physical hunger* subsides by 3 days: yes, this may be a general tendency, but I’ve observed a much wider timescale among my own clients, varying from about 2 to 5 days. Even here there are additional factors which contribute to the actual timescale and the possibility of hunger persisting even later into a fast. (*Note: this refers to a physical, bodily sensation of hunger as opposed to a craving for food.)
  • Mental clarity: yes, some people do experience mental clarity even on their first fast, but this is far from a universal truth. Especially among clients with chronic health issues, I’ve often seen the exact opposite: ‘brain fog’. Low fasting energy levels can be enough in themselves to translate into reduced mental capacity for some people.
  • Working out: yes, some people may continue to enjoy going to the gym, but the vast majority of my clients find any form of exercise a burden. It’s true that the people I work with don’t represent an average cross-section of the entire population, given that a large cohort are fasting with illness of some kind. But even most of my healthy clients (including myself) find that too much exertion during a fast feels heavy and unnatural. Over the years, more vulnerable clients have even reported that working out while fasting subsequently worsens their symptoms of illness.

So what are we to make of all this? Personally, I think it’s fair enough that the people who do feel great while fasting want to tell the whole world about it. Wouldn’t you?… Rather, the takeaway here is that the countless videos which appear on YouTube may not accurately reflect general trends of the fasting experience.

Dr Barker regularly speaks at international conferences on water fasting. Below you’ll find his lecture for The Real Truth About Health conference, as well as a panel conversation with Dr. Alan Goldhamer – one of the most established names in the field.

One well-known study on water fasting records the prevalence of symptoms through extended fasts, the median length of which was 10 days. These symptoms include fatigue (48.2%), nausea (32.2%), insomnia (33.5%), headache (30.1%) and back pain (25.7%).[5] It is important to understand the terminology used to describe these symptoms, because it provides insight into the differing approaches of modern medicine and more traditional health systems.

In everyday fasting parlance, the most common term used to describe the nausea, headaches etc. experienced while fasting is ‘detox symptom’. This term derives from traditional health systems, most of which place implicit importance on the cleansing of accumulated toxins from the body. For instance, it forms a central tenet of naturopathy, which involves the routine use of clinical detoxification therapies to treat a range of medical conditions.[6] Ayurveda even has its own word — Ama — to describe the root of toxicity in the body.

In contrast, the study above completely avoids the use of ‘detox symptom’, choosing the term ‘adverse event’ instead. This is representative of modern medicine in general, which asserts that there is no way to prove that fasting symptoms occur as a result of detox and cleansing. Based purely on the scientific method, this is certainly true: there really is no way to make the leap from observing individual fasting markers and pathways (such as downregulated mTORC1 pathways and upregulated AMPK) to explaining systemic, body-wide sensations such as nausea. Simply, there are too many pathways and steps in the process to be able to draw a direct causal connection. To use the analogy offered in the Introduction, it is a problem of trying to see both the ‘trees’ and the ‘forest’ at the same time — and never the twain shall meet…[7]

Whatever term you choose — ‘detox symptom’ or ‘adverse event’ — there is no question that they can and do occur over 7-10 fasts, playing a major role in the overall lived experience of the fast. Based on over 15 years of personal fasting practice and having worked with over 1000 clients through their own fasts, I would describe the details of a 7-10 fast as follows:

Understandably, the first three days of a 7-10 day water fast generally follow the same process as that which takes place on a shorter 3-day water fast — and I would refer the reader to my article on this subject for more information. Above and beyond this, I would also add that practice does often make perfect, in the sense that many people who repeatedly practise fasting report an overall trend towards a smoother and easier transition in the opening days of a 7-10 day fast.

Physical aspects:
Perhaps most noticeably, the energy drop which typically appears in the first three days of a fast often becomes less pronounced with regular fasting. Energy levels during this period broadly correlate with the development of ketone levels, as confirmed by my clients who choose to measure daily blood ketones. Specifically, once ketones first appear in the fast (typically on Day 2), experienced clients tend to report a faster rise in their ketone levels than those who are fasting for the first time.

Although the repeated practice of shorter fasts may generally lead to a smoother transition at the beginning of the fast, the opposite is also true — and I’ve also worked with numerous experienced clients who sometimes encounter a sudden, unexpected burst of severe nausea and/or vomiting, especially on Days 2 and 3 of their fast. Naturopathic philosophy would explain this as a ‘detox symptom’ presenting through an initial wave of cleansing, triggered by the powerful onset of fasting metabolism. Of course, this theory cannot be proven or disproven by studying individual markers. On a practical level, expert guidance can help when such nausea does present: both in managing the symptoms as well as in diagnosing whether it is simply a natural part of the process or whether it is a red flag to stop the fast.

Emotional/Psychological aspects:
On a psychological level, the opening days of a 7-10 fast can certainly offer challenges, especially in breaking out of the habits of everyday life. Many of my clients are reminded how food plays an almost ever-present role in modern life: in the house, at work, on the street, and on the screen in shows and commercials. In other words, not eating can provide a relentless reminder of eating.

In this sense, the emotional element of hunger is often compounded by the physical element of hunger. It does take a certain number of missed meals before the digestive system begins to accept that the physical ‘habit’ of regular mealtimes has been put on hold through the fast, allowing digestive juices and physical hunger to subside. In the meantime, a rumbling stomach can easily trigger emotional cravings for food.

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Based on measurements of numerous clients who record their blood ketones, the body usually needs 4-6 days for ketone levels to reach their peak. Although there are individual differences, most of them reach approximately 5-6 mmol/l around Day 5 (+/- 1 day). From this point, their ketone levels tend to remain relatively stable for the duration of the fast. This data broadly agrees with the only comparable large-scale study to date, which focused on patients following a low-calorie Buchinger protocol (75-250 kcal/day).[8] Unsurprisingly, the average ketone levels in the study were slightly lower (4 mmol/L) and peak ketosis took longer to achieve than those recorded by my water-fasting clients, given that the caloric intake of the Buchinger protocol in itself provides a source of energy.

I believe that the stabilisation of ketosis during this timeframe has implications for both physical as well as emotional/psychological aspects of the fast (as described below).

Physical aspects:
Days 4-6 often coincides with additional new symptoms, including:

  • foul-smelling breath
  • foul body odour, especially the armpits
  • foul taste in the mouth
  • foul-smelling urine

Naturopathic philosophy would attribute these ‘detox symptoms’ to increased elimination of toxicity through the so-called organs of detoxification, specifically the lungs, the skin, the epithelial tissue of the GI tract and the kidneys, respectively. I personally suspect that the timing here may also be related to having reached peak ketosis, which provides peak energy for fasting metabolism.

On a personal note, 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 foam. It literally tasted like poison. As shocking as it was to experience my own body producing such horrors, it was also strangely inspirational!

Emotional/Psychological aspects:
If the emotional/psychological experience of Days 1-3 tends to be dominated by the withdrawal of everyday habits, Days 4-6 often involve a kind of stabilisation. Many of my clients report a sense of inner peace opening up at around this time, especially if they don’t have to work through their fast. Even among my clients who do work through their fasts, I hear stories of difficult situations with coworkers which were resolved more amicably than might have occurred in everyday life. In short, clients are often surprised by their own inner calm and ability to hold their centre in a stressful situation. Personally, I find it interesting to consider the fact that this kind of ‘inner stabilisation’ also correlates to the timeframe when the body reaches ‘metabolic stabilisation’ in terms of steady ketone levels.

Of course, this is far from a universal experience, and especially those who suffer from emotional cravings can find precisely the opposite: that their patience is wearing thin due to the stress of giving up food. Equally, boredom can become a growing issue for some people at this point: boredom of low energy levels, boredom due to the sensory deprivation of food, boredom of a foul-tasting mouth. As hard as it can be, I would also argue that — under the right circumstances — boredom is the best teacher, and that this is actually an opportunity for personal growth, especially with the right mindset.

Although no studies have explored possible metabolic changes taking place specifically through Days 6-7 of a fast, a clinical shift does often take place: one I regularly observe in both clients as well as myself when I’m fasting.

Physical aspects:
Symptomatically, this period may trigger what is known as a ‘healing crisis’ (discussed below in its own section).

Emotional/psychological aspects:
The human experience of time is, of course, a highly subjective phenomenon. In this sense, the transition from days to a full week can elicit feelings of heaviness, anxiety and/or resistance. In short, a full week can feel unduly long compared to a ‘mere’ 7 days. Understanding the mental hurdles involved when fasting — and knowing how to navigate them — becomes increasingly important from this point onwards.

In my experience, if you choose to move beyond 7 days, into a second week of fasting, Days 8-10 often do correlate with new experiences and challenges. These may involve both objective physical symptoms as well as subjective emotional/psychological feelings.

Physical aspects:
Many clients report a shift in their symptomatology. On the one hand, fasting symptoms which had predominated through the first week of fasting may resolve, leading to a smoother experience. On the other hand, the beginning of the second week can also elicit entirely new symptoms. For some clients, it can be confusing to understand the signals their body is giving them.

Most importantly, it becomes increasingly important from this point onwards to recognise that the likelihood of fasting-related risks and safety issues does increase. In short, the longer you fast, the more likely it is that complications may occur, especially if you suffer from longstanding health issues or take prescription meds. These risks are covered in greater depth in my article on extended fasts of 14, 21, 28-30 and 40 days.

Emotional/psychological aspects:
Just as, on a physical level, passing into the second week can involve both a resolution as well as the development of new symptoms, so the same applies to the ‘mind game’ of a fast. For some people, it can feel like a relief to have broken through the ‘barrier’ of a week. For others, it can feel like an additional burden to have entered a second week — in which case, emotional cravings can also intensify in parallel. There is clearly no single pathway, and this is where the old saying ‘know thyself’ comes increasingly into play.

Time and again I witness that, with the right mindset, fasting does help you to ‘know thyself’ on a deeper level — and, in this sense, offers a huge potential for personal development. At the very least, the physical and emotional/psychological experience of a 7-10 day water fast feels so far removed from the experience of everyday life, that it inherently provides new perspectives on and insights into life.

If modern medicine has a problem with the term ‘detox symptom’, then ‘healing crisis’ causes perhaps even more controversy. In terms of modern medicine, there is no way to identify a causal relationship between the symptoms of this phenomenon with actual healing. On a deeper level, modern medicine tends to avoid the word ‘healing’ altogether with regard to chronic health concerns, applying terms like ‘symptom management’ instead.

Nevertheless, the concept of a ‘healing crisis’ has existed for thousands of years in traditional health systems, from Ayurveda and Chinese medicine to naturopathy[9] and homeopathy.[10] Because of such a lengthy history behind it, I believe it is worth examining the concept of a healing crisis in greater depth.

Based on my own clinical observations, I would define a ‘healing crisis’ as:

The temporary return of old (latent) symptoms or the temporary intensification of current symptoms of a specific illness which may occur as part of the healing process during a water fast. After the given fast, this healing may be experienced as a reduction or full resolution of prior symptoms of illness.

To clarify, my definition of a healing crisis refers exclusively to an intensification of those symptoms of a specific illness which had previously presented prior to the fast, as opposed to an intensification of general fasting symptoms during the fast. (In contrast, some other definitions of healing crisis refer to any intensification of symptoms during a cleansing protocol.)

To be absolutely clear, this is also not to imply that the intensification of old or current symptoms necessarily indicates a healing crisis. Far from it. The opposite can also be true, and under certain circumstances the intensification of symptoms can in fact indicate an adverse response to fasting, an electrolyte disturbance or another medical problem which means that the fast must be broken for safety reasons.

Perhaps the best way to describe a healing crisis is to explain what happened to me on Day 7 of my first 7-day water fast. Prior to my first fast, I used to suffer from chronic sinusitis every winter, to the extent that I often spent much of the day in pain and unable to function normally. At the time, I was also unaware of the full potential benefits of fasting — and so, more than anything, I stumbled into the fast, treating it simply as a challenge to overcome.

Of course, without any real understanding about fasting, I ‘suffered’ greatly throughout my fast with low energy levels and a lot of psychological resistance. But then, something unexpected happened… On Day 7, the area around my sinuses started to ache: not the sharp stabbing pain I was accustomed to during a full flare-up, but rather a dull ache which I couldn’t even really describe as ‘pain’. Furthermore, it was strange. My sinusitis always flared up in winter, but my fast took place in late spring, when the warmer weather prevented the biting cold from triggering it.

I was certainly concerned that this could be the beginning of a flare-up. However, I was much more focused on the fact that I’d be breaking my fast within hours, and thus ending what seemed like seven interminable days of misery. (I do enjoy fasting nowadays!) The ache around my sinuses persisted through the rest of my final day. Within hours of my first meal, however, the ache began to recede until fully disappearing the next morning. I almost forgot about the whole incident, until I read about healing crises a few months later — at which point I realised that, by breaking the fast in the middle of the healing crisis, I might have prevented it from reaching completion. And so, I undertook a second 7-day fast to finish the job. Sure enough, a similar ache in my sinuses returned on Day 2, lasted another 24 hours or so, and then fully receded on its own.

Since then, I’ve never suffered from any sinus issue whatsoever.

It’s important to note that not every long-term resolution of a health issue is accompanied by a dramatic healing crisis. Some clients find that their symptoms of illness begin to disappear during the fast, never to return afterwards. In other situations, other clients find that their symptoms may begin to improve only after the fast, through the refeeding process. This is one reason why it’s so important to follow an appropriate refeeding protocol. In cases like this — where there is a lack of clear fasting symptoms to provide guidance — it can be difficult to know when to end the fast, especially when fasting alone. On the one hand, you don’t want to end prematurely, denying yourself the full potential health benefits. On the other hand, you certainly don’t want to push too hard, extending the fast for too long and incurring greater risks as a result.

Given that fasting reduces the need for digestion — with gastrointestinal activity largely entering a state of ‘hibernation’ as a result — it’s extremely important to consider how and what you eat in the transition period both before and after any fast longer than three days. On a practical level, dietary preparation means gradually lightening up your diet in the days before a 7-10 day fast. This means different things to different people, depending on their specific diet. However, one common element ideally involves an increased intake of vegetables and/or fruit. Where this is contraindicated because of food sensitivities, gut issues (eg. SIBO) or metabolic issues (eg. Type 2 diabetes), it’s extremely important to find an alternative, personalised strategy.

There are several benefits of focussing on vegetables and fruit before a 7-10 day fast. First, they require less energy to digest than proteins,[11] for instance. This allows your body to wind down digestion more quickly at the beginning of the fast, switching more seamlessly into its fasting metabolism. Second, vegetables and fruit contain plenty of fibre to support transit and elimination, thereby helping to clear out digestive remnants before peristalsis (motility) largely ceases during the fast. Third, vegetables and fruit are so-called ‘alkaline-forming’ foods. According to naturopathic theory (but unconfirmed by medical research), alkaline-forming foods can help to counterbalance the mild metabolic acidosis which studies have shown to occur most significantly during the first two weeks of a water fast.[12]

In essence, a refeeding strategy should look like the mirror image of what happens during the dietary preparation before the fast. This means starting with small, light meals focussing mostly on vegetables and/or fruit, and then gradually progressing towards heavier foods. For most people, little or no physical hunger remains at the end of a 7-10 day fast, precisely because of the reduction of gastrointestinal activity during the fast. Along with the natural contraction of the stomach during a 7-10 fast, most people find that small portions provide physical satiety. In short, a slow, gradual refeeding process should feel completely satisfying — at least on a purely physical level.

Most importantly, a slow, gradual refeeding process should also support electrolyte stability and fluid balance, thus reducing the possibility of refeeding syndrome: a potentially dangerous and even life-threatening complication which becomes an increasing risk on longer fasts (described in greater depth in my article on 14, 21, 28-30 and 40 day water fasts). The UK’s National Institute for Health and Care Excellence (NICE) identifies people who have eaten little or nothing for more than five days as being at potential risk of developing refeeding syndrome.[13] So the bottom line is that refeeding after a 7-10 day fast must take place carefully in order to reduce the risk of possible safety issues.

In an ideal world, the pace of refeeding naturally follows the gradual revival of the digestive system in the days following a 7-10 day fast. However, the reality for the vast majority of people is that they are less in tune with their body at the end of their fast, and more at the mercy of their emotional cravings for food and a driving desire to eat. In other words, we return to the fact that a 7-10 day water fast is driven by both physical as well as emotional/psychological elements –- and that often it is the mind game which prevails. In order to help rein in any tendency towards binge-eating and any possibility of refeeding syndrome, an individualised protocol is always advisable.

I remember the exuberance of celebrating the end of my own first 7-day water fast. I had no idea what I was doing! A simple salad quickly become a slice of pizza – which then turned into eating the whole pizza!!! It weighed like an anchor in my stomach for literally days afterwards… And needless to say, I learned my lesson.

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.

Over the long term, many of my clients choose to promote their health with 7-10 day fasts, without any need to contemplate longer 14, 21, 28-30 or 40 fasts. These longer fasts are certainly not something which should be undertaken routinely, or as part of a regular fasting protocol. Rather, their main potential lies in addressing deeper, more exceptional needs, whether in the form of physical health concerns or a spiritual journey.

Many people ask me how often they should undertake a 7-10 day fast. Of course, there isn’t any single, pre-packaged answer, and no evidence-based research has established an optimum frequency. For maintaining good health, I personally find myself drawn to this length of fast perhaps once or twice a year, and many of my clients likewise resonate with this approximate timeframe. However, I would argue that, more important than any particular frequency, is to tune into both body and mind beforehand, feel where the motivation to fast is coming from, and ensure that both body and mind are on board for the journey which lies ahead.

During a 7–10 day water fast, the body undergoes a series of metabolic changes as it adapts to the absence of food. Glycogen stores decline, ketone production increases and the body increasingly relies on stored energy. People may also experience changes in energy, sleep, digestion, mood and physical symptoms. The timing and intensity of these changes vary considerably between individuals.

Many people find that hunger becomes less noticeable after the first few days. However, it varies from person to person and may fluctuate throughout a fast. The reduction of hunger does not necessarily mean that the body has adapted safely or that it is appropriate to continue fasting.

Reported symptoms include fatigue, headaches, nausea, insomnia, dizziness and changes in energy levels. Some people also notice changes in their breath, body odour or taste. New, severe or worsening symptoms may indicate a complication and should be assessed appropriately..

‘Healing crisis’ is a term used in some traditional health systems to describe a temporary return or intensification of symptoms during a period of healing. However, worsening symptoms may also indicate dehydration, electrolyte disturbances or another medical problem. It is important not to assume that symptoms must necessarily be endured or pushed through.

Preparation and refeeding both deserve careful consideration. A light, balanced diet before fasting may help establish a sensible starting point, but it does not remove the potential risks of an extended fast. After 7–10 days without food, reintroducing nutrition requires care because of the possibility of refeeding complications. The appropriate approach depends on factors such as nutritional status, health history and weight changes, and medical guidance may be necessary..

Please feel free to share your thoughts or questions in comments section below!

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[1] Wolska W, Gutowska I, Wszołek A, Żwierełło W. The Role of Intermittent Fasting in the Activation of Autophagy Processes in the Context of Cancer Diseases. Int J Mol Sci. 2025 May 15;26(10):4742. doi: 10.3390/ijms26104742. PMID: 40429883; PMCID: PMC12112746

[2] D. Lee , B. Martinez , D. E. Crocker , R. M. Ortiz . Fasting increases the phosphorylation of AMPK and expression of sirtuin1 in muscle of adult male northern elephant seals (Mirounga angustirostris). Physiol Rep, 5 (4), 2017, e13114, doi: 10.14814/phy2.13114

[3] Singh S, Sargeant TJ. Increasing autophagy with fasting and diet: separating fact from fiction. Biochem Soc Trans. 2026 Oct 28;54(10):1497-1511. doi: 10.1042/BST20260632. PMID: 42865256; PMCID: PMC13673093

[4] Shelton H. The Science and Fine Arts of Fasting. 1934, 1950, 1963. Republished by Martino Publishing 2013. ISBN 978-1-61427-448-3

[5] Finnell, J.S., Saul, B.C., Goldhamer, A.C. et al. Is fasting safe? A chart review of adverse events during medically supervised, water-only fasting. BMC Complement Altern Med 18, 67 (2018). https://doi.org/10.1186/s12906-018-2136-6

[6] Allen J, Montalto M, Lovejoy J, Weber W. Detoxification in naturopathic medicine: a survey. J Altern Complement Med. 2011 Dec;17(12):1175-80. doi: 10.1089/acm.2010.0572. Epub 2011 Nov 21. PMID: 22103982; PMCID: PMC3239317

[7] Kipling, Rudyard. The Ballad of East and West. The Pioneer. 1889 Dec.

[8] Grundler F, Mesnage R, Ruppert PMM, Kouretas D, Wilhelmi de Toledo F. Long-Term Fasting-Induced Ketosis in 1610 Subjects: Metabolic Regulation and Safety. Nutrients. 2024 Jun 13;16(12):1849. doi: 10.3390/nu16121849. PMID: 38931204; PMCID: PMC11206495

[9] Derin, C. The Healing Crisis. Naturopathic Doctor News and Review. 2007 May. https://ndnr.com/the-healing-crisis/

[10] Little, D. Crisis in Classical and Contemporary Thought. Homeopathy Papers. 2007 June. https://hpathy.com/homeopathy-papers/crisis-classical-contemporary-thought/

[11] Want to Manage Weight? Pack in the Protein. University Hospitals, Cleveland. 2025, May. https://www.uhhospitals.org/blog/articles/2025/05/want-to-manage-weight-pack-in-the-protein

[12] Rapoport A, From G, Husdan H. Metabolic studies in prolonged fasting. Metabolism – Clinical and Experimental. 1965 14, 31-46. https://doi.org/10.1016/0026-0495(65)90079-X

[13] Nutritional Support for Adults: Oral Nutrition Support, Enteral Tube Feeding and Parenteral Nutrition. NICE Clincical Guidance. 2017, Aug. https://www.nice.org.uk/guidance/cg32/chapter/Recommendations


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292 responses to “7-10 Day Water Fasts: What to Expect Day by Day”

  1. 2 questions:
    I’m on day 8 of a planned 10 day waterfast, and had some calf cramping. So I took some electrolytes this morning, which after reading your articles I see may slow down the healing aspect of the fast. My question is, for how long?
    Second,
    I have Celiac. Have you seen any complete healing (cure) of celiac? Or just recovery from the damage done by celiac?

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

      Hi Dan,
      Thanks for writing. It’s hard to say how long the electrolytes will remain in your system, because it depends on the specific mixture you used. If it was simply a topical magnesium gel or oil, don’t worry about it – there will be no negative impact. If it was a broad-spectrum electrolyte, this is a different question. Sodium has the greatest negative impact on fasting metabolism because it forces the body to retain extra fluid. Based on what I’ve observed with client symptoms, the sodium usually stays in your system for at least 5-7 additional days.

      When it comes to true Celiac disease (confirmed via genetic testing and a biopsy), there can be various outcomes. Whether or not you fully cure Celiac, you may find that your digestive symptoms benefit from an extended break from food. The main thing is to tread very carefully after your fast, to test the degree of your own healing. For a full resolution of symptoms, however, you may need a significantly longer fast.

      Hope this helps,
      Tallis

      1. Ah – yes, I added a pinch of sodium… this fast is done from a healing perspective. Thank you.
        Celiac – By full healing do you mean cure? In other words, have you seen Celiacs end their immune-response to gluten? Is this a treatment modality that can achieve that possible result? My primary reason to fast is spiritual, but I am also keenly aware of the healing aspects of it, and would like to know where to set my hopes… and whether to attempt a longer fast for the purpose of deeper healing.

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

          Hi again,
          I’ve had some clients with confirmed Celiac disease fully reverse their symptoms, but none of them has gone on to have a biopsy to confirm the full healing. If they’re feeling 100%, I can understand why they want to avoid this! However, not all my clients achieve a full resolution, although most do experience improvement in their symptoms. Whether repeated fasting would eventually lead to a full healing in such cases is something that only the future can reveal!
          Tallis

  2. Hello Tallis,
    Any tips or suggestions on how to prepare my body for 7 days fasting and how far before i start?

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

      Hi Joanne,
      Thanks for writing. The main thing is to lighten up your diet and make it more alkaline-forming in the days before your fast. Exactly how to do this can vary widely, and it’s something I discuss with every client individually in our pre-fasting consultation. For instance, you could drastically cut back on heavier foods in the days beforehand, but if doing so leaves you feeling deprived even before your fast begins, is that really the best headspace to be in? Important factors in how you devise a preparatory diet should include where your dietary starting point is, your prior experience with fasting, and the degree of emotional cravings for food in everyday life.
      Hope this helps,
      Tallis

  3. Hello! I completed an 8 day water fast yesterday, and today I woke up with a rash similar to hives on my arms and legs. Do you have any idea what this could be? I personally don’t think it was from the food I ate last night to break my fast. I appreciate your help!

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

      Hi Kellie,
      Thanks for sharing. Skin issues such as itches and rashes are very common among my clients during and immediately after fasting. According to naturopathic philosophy, itches and rashes typically develop when the liver is running to full capacity neutralising toxins, which means that the skin has to ‘pick up the slack’. Whether or not this is the case for you would require a more in-depth look at what was going on both during your fast in terms of symptoms as well as your general state of health beforehand.
      When skin issues do develop they can have a nasty tendency to linger, so it’s important to make sure your post-fasting diet doesn’t contribute to the problem.
      Hope this helps,
      Tallis

  4. You specify 7-10 day Fast. Could 6-10day Fast work as well. I am doing a 6 day Fast. Is there much benefit in doing a 7 day fast vs 6 day. I have NSCLC, Stage 1A, surgerical resction, NED, active surveillance.

    Like Jason, while Fasting my BG goes down to 40-50, sometimes in upper 30’s. I feel fine. Can not find anyone who knows about this or can explain it and whether this is dangerous. Have been doing 20 gram carb Keto for 4-mons. My Ketos go to 7.5-8.5 while Fasting. Is that dangerous?

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

      Hi Melissa,
      Thanks for sharing. Among my clients, low blood glucose levels are often accompanied by very solid ketone levels on a fast, meaning that the overall energy available to your body may be adequate – and consequently you feel fine. However, very low blood glucose levels are also a potential safety issue for obvious reasons, so it’s always worth erring on the side of safety.

      A 6-day fast may elicit some benefits for you, but it’s highly unlikely to have much of an impact on a serious illness like cancer. When I’m working with a client suffering from any serious illness, a big part of our initial consultation is devoted to exploring the various possible fasting protocols, aiming to maximise efficacy and minimise risk. This may involve looking at much longer lengths of fast, depending on the client’s strength.
      Hope this helps,
      Tallis

      1. Stephen Evensen Avatar
        Stephen Evensen

        Dear Tallis,

        This is a very interesting point. Can you please direct me to literature that discusses on the anti-cancer effects of fasting? I’m aware of Thomas Seyfried. Perhaps there are others publishing in mainstream journals?

        Thanks,
        Stephen

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

          Hi Stephen,
          I’m afraid there isn’t much in the way of mainstream journals which looks into the anti-cancer effects of extended fasting. Yes, there are articles which deal with the effect of autophagy on individual cancer markers, but this is entirely different from the highly complex interaction of virtually countless enzymes, hormones and other factors which actually take place in a live human being. There simply isn’t much financial incentive for anyone to fund research, and there’s also a lot of vested interest in maintaining the status quo in terms of the current therapies. My comments here are based on direct clinical experience working with numerous clients suffering from cancer.
          All the best,
          Tallis

  5. Thank you so much for this website, I’ve found it very helpful and encouraging. I generally live a low-carb lifestyle with pretty consistent intermittent fasting and have done several 3 day fasts without issue. I’m currently on day 4 of a 7 day fast and my blood sugar is very low – fluctuating between 40-50. Most mainstream medical resources suggest that this is incredibly dangerous and that I should perhaps be in a coma. However, I feel ok – very slight headache, minor anxiety, but generally pretty good. I’ve listened a lot to Dr. Pradip Jamnadas, and found him to be very interesting and helpful as well – in one of his talks he mentioned patients having blood sugar as low as 30 and being perfectly fine, which is one reason I haven’t panicked. But that was just one comment in one video and I’m looking for a little more confidence here. And so anyway, I’m curious if there is any data on actual blood sugar levels during extended fasts or if you have any thoughts on this. Thanks!

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

      Hi Jason,
      Thanks for writing, and I’m glad you’re finding the website useful. With regard to low blood sugar levels, I agree with Dr Pradip Jamnadas that many — but not necessarily all — people can tolerate much lower levels than what is normally considered normal or even safe. I too have had clients whose blood glucose has sunk into the 30s without any negative repercussions.

      However, it’s also true that I’ve had other clients who encounter significant difficulties in the 50s. So the moral of the story is that we’re all different, and it’s extremely over-simplistic if not downright dangerous to assume that any particular blood sugar levels are ‘good’ or ‘bad’ in their own right. As in so many areas of water fasting, this is hugely important to respect, and especially when inexperienced people understandably go online to try and find ‘the answer’. So often, it is the CONTEXT and not the actual values of any test which provide the greatest insight.
      Hope this helps,
      Tallis

  6. I have a group of people and my wife, and we do a 7-day water fast. We’ve been doing this for the past three years. We range in age from 40-53 years. We ONLY drink spring water and no supplements (salt, potassium, magnesium, zero-calorie drinks, coffee, lemon, etc.). What is your feeling about taking supplements while fasting? Thank you

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

      Hi Leroy,
      Thanks for writing. Congratulations on your fasting practice – it’s brilliant to be able to fast together like this! About supplements: I’d refer you to my article on the website here:
      https://waterfasting.org/pills-powders-and-potions-the-reality-of-taking-supplements-while-fasting/

      All the best,
      Tallis

  7. Hey there,I am currently taking an antipsychotic and I think I need to get off the med to truly water fast. But I have really bad insomnia when I don’t take the med. i barely sleep at all. Can I still detox from heavy metals when water fasting if I don’t sleep at all? Or is sufficient sleep an important part of water fasting?

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

      Hi Lasan,
      Thanks for sharing. Water fasting may well help the body cleanse from heavy metals, as confirmed by clients’ tests before and after a water fast. It’s true that sleep requirements may drop during a fast, but you’re not going to want or even be able to fast if you don’t sleep at all. Some of the most difficult clients I work with involve just this: cases of severe insomnia, the involvement of sleep meds and how to manage the whole situation.

      I wouldn’t recommend trying to juggle all the variables here without some kind of expert coaching through your fast – it’s very much like walking a tightrope! Also, please be aware that only your prescribing clinician is officially authorised to change dosage of your meds. An appropriate withdrawal schedule would be extremely important for someone like you when fasting. This really is a safety issue.
      Hope this helps,
      Tallis

  8. Great article, thanks Tallis.

    I’ve done a 9 day fast on a retreat in Thailand, some 20 years ago and the experience stayed with me ever since. I loved it. I’ve since eaten healthily and done occasional 1 day fasts. for the last 18 months I’ve fasted daily in leaving 16 hours (between 8pm and 12 noon), more because I found I rushed through breakfast in the am rather than enjoy it – and I very quickly felt the benefit.

    Now, as a fit, strong and pretty healthy 53 year old – I’m going to work to a 7-10 day fast to ‘reset/refresh/recharge’ my system in March/Spring (UK). I’m going to take myself (and my Labrador!) to camp comfortably in a forest. I’ll follow your great guidance pre and post the fast, and may sign up for a consultation with you nearer the time. I had one question in the planning: do you recommend a colonic irrigation session during a 7-10 day fast to rid myself of toxins and waste? If so when, and should I have more than one?

    Many thanks,
    Ross

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

      Hi Ross,
      Thanks for writing. Sounds like you’ll be headed to a beautiful and perfectly serene environment for your fast this spring. To answer your question: everything you do on a fast has pros and cons, but I’d be very careful with regard to colonics. The body becomes much more sensitive to everything you do when fasting. If you don’t already have plenty of experience with them, it may make sense to do an enema instead, if symptoms arise suggesting that you’d benefit from one (which among my clients happens in about half the cases on fasts of this length). Very happy to meet you for a consultation when the time is right.
      All the best,
      Tallis

      1. Perfect. Thanks, Tallis. I’ll be in touch. And, on the enema – when should that be done? before, during, after a 7 day fast?

        Very best,
        Ross

  9. Hi, would you recommend a 10-14 day water fast if I am very skinny? I am looking to do a fast for health benefits as I have stomach/esophagus issues, but I do not want to loose too much weight as I always struggled to gain weight. Thanks.

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

      Hi VV,
      Thanks for writing. I’m afraid there’s no way I can recommend a specific length of fast in absolute terms based on the relative description of ‘very skinny’. One thing is for sure, when I’m working with a very skinny client, it’s extremely important to get the length right: aiming to maximise the length for optimum benefits while not overstepping the limit, which could prove dangerous. It’s like walking a tightrope, and I’d recommend getting professional advice from an expert such as myself before attempting this yourself!
      All the best,
      Tallis

  10. This was a great article! I’ve spent all day trying to find a voice like this one! Thank you!!

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

      Hi Redwing,
      You’re welcome – and glad you’re finding the website helpful. I hope you’ll find that the other articles have a similar voice :-).
      Tallis

  11. 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 initially need to work with short fasts for safety reasons. Many of my clients find that, through the combination of short fasts and appropriate nutrition, they are able to gradually put on some healthy weight over many months — at which point they may contemplate a longer fast. 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,
      Tallis

      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,
          Tallis

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

  12. 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!

    Anabel

    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. According to naturopathic philosophy, it was most likely to have 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 — forcing the skin to ‘pick up the slack’. 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, I would expect that yours will probably resolve by itself.
      All the best,
      Tallis

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