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. Hi Tallis – I’ve completed numerous water fasts ranging from 5-10 days over the past several years, and I’ve noticed that I get very chapped lips around day 4 or 5 of the fast. Further, my eyes also seem to get dry, which makes contacts much more bothersome, and in one case, I had very sharp pain in one eye that caused me to break a fast. I try to listen to my body, so I allow my level of thirst to dictate how much water I drink. I’d very much appreciate any perspective you have on whether the dryness is a common symptom you come across and what I may be doing wrong or what could be done to help. Thank you!

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

      Hi Jonathan,
      Thanks for writing. Many people experience dryness of some form (whether dry skin, chapped lips etc.) during extended water fasting. To a degree, the passing of toxins through the skin may cause this, but, more fundamentally, the cleansing of a water fast itself involves an element of dehydration caused by cortisol: the hormone which mobilises fat from your adipose tissue to burn through ketosis. This is totally normal, and, symptomatically, goes above and beyond whatever your fluid intake may be. Although many people’s bodies manage this smoothly, I do often have to help clients navigate a path which continues to enable the deepest fasting metabolism, while also mitigating the effects of this natural process.
      All the best,
      Tallis

  2. Hello again,
    So this was my second time i did the 7 day fast. I broke it with Tomatoes with garlic, waited 50min-1H, I had quarter of an apple and one date and 20min later I ate two small-medium bowls of Sauerkraut Soup from your recipes. Then 1H later got the call to the bathroom. First parts were old food which was solid but after that all was liquid. Any idea why such an reaction? After that I ate 1 apple and 2 dates and was ok and did not have any urge to go to the bathroom. In my first fast it did not happen but after my soup i had green shake and later in the evening the sauerkraut soup. Was I too fast with eating the sauerkraut soup? I did not feel any stomach upset but it just happened.

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

      Hi Bart,
      Thanks for writing and my apologies for not having replied earlier. Your comment somehow slipped in under the radar! Digestive responses to breaking a fast vary from person to person, as well as from fast to fast. Sauerkraut can certainly help to elicit a bowel movement after a fast. But it also sounds to me that you may have experienced a combination of old material released from before the fast followed by toxic bile (ie a liquid) produced during the fast. The transit time was awfully fast for it to have been the actual sauerkraut, but the sauerkraut could easily have acted as a trigger to eliminate what was already in the colon.
      All the best,
      Tallis

      1. So it takes 7-10 days of water fasting to fully detox the body. Does that include regular/filtered water or distilled water? Can I fully detox heavy metal in 7-10 days with filtered water?

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

          Hi Lasan,
          Thanks for writing. Yes, regular 7-10 day water fasts (@1-3 times a year) tend to be all that a healthy person needs to promote health. When someone is suffering from deeper health issues, though, it may often be necessary to devote more time to healing. Based on client outcomes, I believe that water fasting may be one of the most powerful ways to detox from heavy metal contamination, but when labs confirm an improvement it’s usually after longer fasts — and you may need somewhere in the region of 21(+) days, depending on the level of exposure. My clients often report the taste of heavy metals in their mouths when the fast has reached the point, so in many cases there may be clear feedback from the body.
          There’s no need to drink distilled water on a fast, but do make sure that it is from a good, clean source!
          Hope this helps,
          Tallis

  3. Hi, Tallis, I noticed in one of your previous posts that taking electrolytes inhibits healing during a fast. What’s the reason for this? Are there any studies or other links? I exercise with some vigor during multi day fasts and thus lose electrolytes at an elevated rate. Thanks!

  4. Would it be safe for me to smoke cigarettes or use a nicotine patch while doing an extended fast of 10 or 14 days? If it would be safe, would it affect healing and autophagy? Also, is it possible to continue taking prescription medication during a fast of that length?

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

      Hi Hazel,
      Thanks for writing. Everything you do during a fast is going to have a some kind of impact on the outcome. Generally speaking, the best is to keep it pure: only water. However, when prescription medications are involved, it really depends on the specific medication – sometimes it’s necessary to continue taking it, sometimes it’s necessary to gradually reduce dosage and sometimes it’s necessary to be off it completely. In these cases, it would be best to work with both a fasting expert as well as your prescribing clinician in order to devise an appropriate withdrawal schedule if necessary. (Only a doctor is officially authorised to make changes to your meds.)

      In terms of smoking, nicotine is both a toxin in itself (which burdens the body during a fast) as well as being specifically a stimulant (which raises metabolism, when instead the body needs to be slowing metabolism down in order to maximise parasympathetic nervous system upregulation). However, I do work with clients who use fasting specifically to quit smoking – and fasting can actually make the process easier than trying to do it in everyday life. You might find my article on fasting with addictions useful: https://waterfasting.org/water-fasting-for-addictions/

      Hope this helps,
      Tallis

  5. I have what might be a foolish question. In two of my fasts I had great constipation. The most recent, a ten day fast on the ninth day I felt strongly that I needed to poop. I tried to but I couldn’t, and it was very painful.

    I did an enema and was able to poop, but it was very painful, and the poop was large and hard. My prefast diet was mainly fruit and vegetables, however, three to four days before the fast I had a small steak. Is this possibly the cause of my constipation?

    I have done many fasts and this only occurred on two of them.

  6. This is great information. I recently went on a forty day fast, but on the thirty third day I had some problems, which turned out to be sodium defficiency. I only took water the entire 33 days, but I quit at the end of day 33.

    I know of many who claim on the internet you need to take salt every day. I think that’s foolish, but evidently I needed to take a little salt … had I done that I think I could have made my 40 days. I’m planning another 40 day fast, but this time I’m considering taking one himilayan salt water drink on the third week. Yout thoughts?

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

      Hi Adel,
      Thanks for writing. I’ve only ever had a client run into sodium deficiency on rare occasions – and there’s no question that the longer the fast, the greater the risk. The bottom line is that sodium deficiency is a major safety issue which MUST be identified as soon as possible if it starts to develop. This is where fasting alone can itself become a risk, if you can’t identify the symptoms. Factors which may have come into play in your case were: your pre-fasting diet, your pre-fasting intake of added sodium, your fluid intake, and most importantly your health history.

      Healthy humans are designed to fast on plain water – just as we’ve done for hundreds of thousands of years, before the days that companies started trying to sell us electrolytes. However, those suffering from chronic health issues may have greater trouble maintaining electrolyte balance on their fast, and this is where expert guidance can help.

      Hope this helps,
      Tallis

      1. I did multiple 7 Days fasting and i had deficiency in sodium once to the point of fainting. And i hab defienciency in potassium another time. And defienciency in magnesium another. I guess it depend of the person and now i take supplement and my fast is less difficult.

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

          Hi Sarah,
          Thanks for writing. This confirms my last reply to you. It would definitely be worth seeking expert advice in a full consultation before trying to fast again. Although fasting may often lead to promoting health, it can also lead to deteriorating health over the long term if you don’t have the nutrient reserves to support it.
          All the best,
          Tallis

  7. Thank you for your insightful post, Tallis. I am currently on day 5 of a water fast and am considering how long to go. Do you know of peer-reviewed literature that discusses the benefits at 6,7,8,9,10, etc. days relative to the benefits I am already seeing?

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

      Hi Stephen,
      Thanks for your question. No, I don’t know of any peer-reviewed literature covering specific benefits over specific days of a fast. Although you can find such claims on random blogs and on fasting apps, the truth is that I don’t believe any of it! Over the years of working with hundreds of clients, it’s clear that (1) different people may experience different benefits at a different rate and (2) a fast doesn’t work on ‘x’ and then ‘y’ + ‘z’ sequentially. Rather, the fast may work on multiple issues simultaneously, and it’s only a question of which particular issues presents in the foreground in terms of symptoms and healing crises.
      Hope this helps,
      Tallis

  8. I water fast regularly, maybe 2-3 times a year. It always amazes me how it kicks inflammation and helps refocus my attitude toward eating healthier foods.
    I do have an issue that I don’t hear discussed so I wonder if it’s abnormal. I pretty much consistently dump bile throughout the fast via a bright yellow liquid
    through the bowels. Is this abnormal?

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

      Hi CJ,
      Thanks for writing. Glad that you find fasting to be a useful tool.
      One of the biggest changes which takes place during a fast is liver function, and this may also have a knock-on effect to bile. For many clients this does lead to a lot of it being produced during the fast, and clearly your body does not want to hold on to it – which is perfectly normal. However, this symptom may suggest that perhaps your liver is overworked or stressed in everyday life, because a ‘happy’ liver would have less need to produce such a large quantity of bile while fasting.
      All the best,
      Tallis

  9. Love your site. Sharp contrast to the tonne of un-informed and mis-informed info around on this topic. I just wound up a 7-day water+sea salt (+1c/d coffee) water fast. Previously did a couple of 5-D, one 7-D and one 10-D, all quite easy. But this one kicked my butt. Extensive reading/googling can’t find relevant advice/explanations. Pre-fast 2 days of OMAD, low-carb. Fast day 1,2 smooth sailing, including moderate exercise. D3 ok, but excessive belching started. D4-5 belching worsened, deep and painful, 8-10/hr, with increasing acid reflux, also energy WAY down (previous fasts D3+ was energy up). D5 tried 1-2 spoons of homemade live yogurt and chamomile tea to quell the acid. Very slight improvement. D6 acid finally gone, belching down ~40%, flatulence replaced it. Energy still like the walking dead. D7, prior to evening fast-break, energy still awful, partner thought I was going to collapse. Broke with 3 very small feeds of roasted carrot/burdock root and avocado w/olive oil/vinegar dressing, spaced several hours. Energy and dizziness somewhat improved, expect tmrw should improve further. What the heck was going on? Suspect all this was somehow an epic battle amongst various gut denizens, but what might they have been metabolizing to convert to huge volumes of gas? My own intestinal epithelium or one another ? None of the experts in the several fasting books and many website have anything relevant. Wonder if you’ve any thoughts.. Thx

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

      Hi Reg,
      Thanks for sharing, and glad you’ve found the website useful. There may be a variety of causes for gas during a fast. Yes, it may be die-off from your gut biome. It may also simply be from remnants of your last few meals, especially if you were on a keto diet and didn’t do much in the way of a dietary transition. Gas may also be caused as an end-product of fasting metabolism (CO2). In the gut, this may take place when the building blocks of acids (produced through detoxification) leach through the epithelial lining of the GI tract and react with the layer of mucous there.
      All the best,
      Tallis

  10. Hi, thanks for great info! I’m on my 6th day and have some questions.
    – My urine smells awful, like pork gone bad, is this normal? toxins?
    – The reason for fasting, is chronic inflammation in the knees, do you think this might cure it? How long would you recommend to go? I’ve already had some tension release in my back!

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

      Hi Aleks,
      Thanks for writing. Glad you’ve noticed some changes taking place :-). Yes, on a fast it’s totally normal for the smell of urine to change. (In everyday life these changes are NOT normal, and you should seek medical advice instead.) It may reflect higher acidity and toxins, and may well say something about your diet prior to the fast as well. To answer your other question: fasting is great for lowering inflammation, and it may well help your knees. The main question for me is whether the improvement is temporary or permanent. It’s hard to say how long you’d need to fast, since this may depend on how severe the issue is, how many other issues your body also has to work on (including simple toxic load if you’ve not already done much fasting) and the overall strength of your immune system.
      All the best,
      Tallis

  11. Hello, great site with great info. I have been doing 24H water fasts for almost 10 years. I decided to try 7 day fast. I feel normal, just slightly missing food. I am at the end of day 5. What i dont understand why there is no bowel movement from days before fasting. I feel warm feeling in my stomach or intestines but no bowel movement. I feel some urge but nothing is happening. Is not this unhealthy to hold to food that was processed and should be removed naturally? Why body stopped and does not empty the bowels?
    Any way to help it?

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

      Hi Bart,
      Apologies for the delay in responding. There’s been a glitch with messaging on the website recently.
      If your digestion switched off particularly quickly or if you didn’t introduce a pre-fasting dietary transition, then it certainly is possible to experience no bowel movements from the onset of the fast. Whether this is a problem or not may depend on the length of the fast and the quantity/quality of food you’d been eating before the fast. If it does turn out to be a problem, you may start to feel progressively lower energy levels (which can be difficult to distinguish from the normal lower energy levels of a fast) and some kind of abdominal symptom. If you have any doubts, it may make sense to do a simple enema to solve the problem. However, please be aware that repeated enemas may contribute to electrolyte deficiency, which is a safety issue!
      All the best,
      Tallis

      1. thx for the reply. Digestion kicked in on the 6th day and I had 2 bowel movements that day. I felt great during the fast like nothing happened except the feeling of a need to go to the bathroom with no success at the begining. Was little bored due to no food but all went well. Slept well felt good. At day 7 and 20H body was signaling maybe you should continue but I stopped as I planned the food already. I used the recipes posted on your website to break it and it was all fantastic. Tomato soup was so simple and so good. Hard to tell if how my body benefited from it but I am glad that I tried and now I understand what means to not to eat for a longer time. Truth is I still don’t know what is starvation (7-8 days is too short) and I am grateful for all the food I always have.

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

          Hi again Bart,
          Glad everything went smoothly. Don’t worry: even if obvious health benefits aren’t immediately obvious, you may find subtle improvements in the weeks to come. And even if the only benefit was a greater gratitude for the food you eat, that in itself is a huge gift 🙂
          Tallis

  12. HI, I am on day 8 of an intended 14+ day water only fast. I have had an embarrassing issue today, and am wondering if it means I am doing something wrong, or should end my fast immediately. First 7 days, as expected, nothing in, nothing out (on the solid side) but today at work I felt like I needed to pass gas, and I sharted (hope you are familiar with the term). Why, and how could I prevent this moving forward?

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

      Hi Phil,
      Thanks for sharing. Don’t worry, it’s unlikely you’re doing anything wrong. What may have happened is that, for a variety of reasons, toxins and waste-products accumulated in the gut. This may lead to gas, mucous and liquid bile build-up, which can want to come out. The rest speaks for itself!
      Probably no need to change anything – except to fast regularly, which may prevent toxins from excessively building up in the first place. Also, an appropriate dietary transition before the fast usually helps.
      All the best,
      Tallis

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