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. Dear Dr Tallis Barker

    First of all, thank you very much for making such an i formative website on waterfasting. I have not yet fasted, and I am trying to read as much as I can before I do.
    I understand that it is best to start with a 24-36 hour fast and gradually move into the 3 day fast. I was glong to attempt a 10+ day fast right out the gate, and I am glad to learn otherwise.
    I was wondering if you would be able to answer a question:
    Once I am at the point where I feel comfortable doing a 7-10 day fast, is it dangerous to do so without any medical assistance or guidance? I am a healthy, active 36 year old women, I follow a plant-based lifestyle, am not on any medication and as far as I know, have no under lying illnesses.

    Thank you!

    1. Tallis Barker Ph.D. Avatar
      Tallis Barker Ph.D.

      Dear Claudia,
      Thanks for writing, and sorry for the slow response. (I’ve actually been moving house this last week, and things are rather busy at the moment!)
      To answer your question, fasting is as natural as eating. Especially since you’re fundamentally healthy, there’s no reason it should be dangerous for you. Given your plant-based diet, the transition into fasting may actually be relatively easy for you. If you’re fundamentally healthy, there’s no physical reason you shouldn’t attempt a 7-10 day fast the very first time – the only reason I recommend starting with shorter fasts is because most people find it psychologically difficult to give up food for such a long time!
      Especially since you don’t have any immediate health concerns you’d like to address, there’s also no reason to immediately dive into a more extended fast. So my advice is to start slow, fast for as long as it feels manageable, and take it from there 🙂
      All the best,
      Tallis

  2. Hey. I have been doing 36 hour fasts, once per week, for 2 years, then I moved on to two days separate days per week for 3 years. I also did four 3-day fasts. I decided to do a 7 day fast, which I completed. Your article helped me to decide that it’s the best for me, because I felt this enthusiasm to go into it.

    I want to ask you one thing: my first 4 days were super smooth, I was super energetic, no hunger, no craving, no weakness. Day 5 was half good, half crash, had to lie down for half a day. Day 6 was total crash, and day 7 was crash, but lighter than 6th day. I have been reading what other people experienced during 7 day fasts and everyone says that the first days are the most difficult, but for me it was in reverse. Do you know what could this mean?

    I’m 1.80m height and 75 kg, so pretty average (I would say a little underweight).

    1. Tallis Barker Ph.D. Avatar
      Tallis Barker Ph.D.

      Hi Mihai,

      Thanks for sharing. First of all, this just goes to show (yet again): don’t believe everything you read on the internet – and especially when it comes to fasting!

      Your own experience does diverge from the ‘average’ experience of a 7-day fast (if there is such a thing as an average experience…). The reason for this may be in the way you prepared so thoroughly for it over the previous years. Most people feel lousy in the first few days because their body doesn’t know how to efficiently access ketosis. They simply haven’t had enough practice in getting there. After ketosis is up and running, though, they have more energy and feel better – even if there are subsequent waves of fasting symptoms.

      Because you’ve taken such a long time in moving from 36 hours to 2 days and then on to 3 days, it means that you’ve had LOTS of practice of gently getting into ketosis. Your body knows how to do it, and so there are no problems. This may be why the first few days of your 7-day fast went so smoothly – because practice does make perfect :-). In most fasts, what happens is that the body gets into ketosis, then it gives you a grace period for a day or two before diving into a deeper fasting metabolism with possible symptoms to show for it. So in your case, this may be what happened on Day 6, with things smoothing out again by Day 7. I can only speculate based on what I observe among my own clients, but if you had continued the fast into Day 8, I do suspect that you would have felt fine again.

      All the best,
      Tallis

      1. Hello Tallis,

        Thank you for your fast reply. That makes sense. From what I read on your site and comparing it to my direct experience I could really tell that you know what you’re talking about. I will for sure repeat the 7-day fasting and aim to go to 21 then 40. I guess it’s better to take it gradually.

        This extended fast really got me even more hyped about fasting in general. I’m a big eater, usually falling prey to the desire of taste, more than hunger, and fasting proves to be a good way to also discipline my mind. Just wanted to share this and to thank you for your effort in making fasting more accessible to people. It’s really a golden technique for the times we live in now, where almost all the food is ‘poisoned’ and in consumerist societies we tend to overeat.

        All the best to you too!
        Mihai

        1. Tallis Barker Ph.D. Avatar
          Tallis Barker Ph.D.

          Hi Mihai,
          Glad your 7-day fast was such a positive experience! Once you feel that 7 days is “no big deal”, you may find that, psychologically, you’ll be able to jump to pretty much any length of fast afterwards. So much of our lives is geared around a weekly cycle that to be able to fast comfortably for 7 days means that, psychologically, longer fast may feel simply like a repetition of this weekly and already familiar cycle.
          Keep it up!
          Tallis

  3. I started a extended fast after wanting to detox my body and heal myself of ailments. I did not properly prepare for the fast and am having bowel issues(constipation). I have a lot more healing to do and do not want to break my fast. Do you suggest Epsom salt cleanse to help me rid my body of the waste and continue on my fast. Thank you.

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Hi Kayla,

      Sorry to hear about the way things are going. This is precisely why making a dietary transition before a fast is so important! Never mind: learning by doing :-).

      Now that you’re stuck in the situation, I’d recommend an enema instead of an Epsom salt cleanse. The latter is simply too aggressive, effectively forcing your body to react to a chemical stimulus. Even though an Epsom salt flush may have the desired effect, it’s likely to come at a cost. Many people end up with cramping as a result, and sometimes severely. At the very least it forces your digestive system to leap into action when it should be switching off instead. An enema, on the other hand, simply use water (with a little gravity) to accomplish the same goal, with your intestines much less actively involved.

      Hope this helps,
      Tallis

  4. Thank you for writing about the ego and fasting. It’s very helpful. I have two questions. I immediately get foot cramps when I fast. What is this from? I did a 7 day coconut water fast and had heart palpitations or fluttering on day 7. Is this normal and part of the process? Should I continue fasting if I feel this again?
    Thanks for your help. ❤️

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Hi Kae,

      Thanks for writing. I’ll dive right in and get to the point.

      It’s possible that your two symptoms are related. Assuming you’re not dehydrated, cramps are usually caused by low levels of magnesium. When this is the case, the cramps also tend to occur most frequently in the extremities: feet, toes, hands, fingers. On a cellular level, calcium and magnesium work in conjunction, with calcium causing your muscles to contract and magnesium causing them to relax and open up again. This is why magnesium supplements are commonly prescribed for people who tend to cramp easily.

      More seriously, low levels of magnesium can also affect the heart, causing palpitations. This is very different from the kind of heavy, pounding heart which often naturally accompanies detox (similar in feeling and function to when your heart is pounding during the flu). I don’t want to scare you, but you definitely want to pay attention to heart palpitations! If magnesium levels drop too low, it can ultimately lead to cardiac arrest.

      Before you do any more fasting, I would suggest getting a blood test and seeking medical advice. A comprehensive metabolic panel (also called a Chem 12 or Chem 14) will clearly show how your magnesium levels are doing in everyday life. If you cramp so soon after beginning a water fast, this does suggest that your everyday magnesium levels are low. Next time you water fast, I’d also suggest getting a blood test on Day 3 or 4: after you’ve largely made the switch over to ketosis but before there’s any chance of danger to your heart. When you’re fasting and are in ketosis, certain electrolytes such as magnesium are used differently, and therefore their levels in the blood can differ compared to everyday life. If you do get a blood test because of potential concerns about your heart, it’s also important to check that sodium, potassium and phosphorus levels are also in the normal range.

      For the vast majority of people, fasting is completely safe in terms of its impact on the heart. If you are one of the exceptions, though, it’s essential to seek medical advice first. It’s always better to err on the side of safety

      Hope this helps,
      Tallis

  5. Dear Tallis,

    I plan to start my first 10 days fasting at 23.06.2019.
    I’m curious about the water intake due to the quite hot water we have here.
    Do I need to quit or decrease the intensity of my running and weightlifting sessions?
    I’m already done several 3 days fasting only with water and I noticed that my body almost fighting against my will to do any sport.
    Anyways I just want to thank you for all the informations you share.
    Extremely helpful and easily understandable.
    Have a nice day!

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Szia Árpád!

      (That’s Hungarian for “Hi Arpad”, but we’d better continue in English!) Thanks for your question. The key thing in water fasting is to listen to your body. It’s no coincidence your body has resisted you on previous fasts: working out while water fasting may cause damage! All the details are found in this video:

      https://waterfasting.org/2018/11/27/working-out-and-exercise-during-a-water-fast-is-it-safe/

      As far as water intake goes, follow your body and aim to drink to thirst – with a baseline of at least 1 litre per day in order to avoid dehydration.

      Hope this helps!
      Minden jót és sok sikert a böjtöddel,
      Tallis

  6. Hello Tallis,

    Thank you for such an informative site- thinking of a 24 hr fast starting Sunday night. However, I have kickboxing class Monday morning, so, is it ok if I have black tea (Darjeeling) with a small handful (less than 1/4 cup) raw walnuts? Or, just a small cup of coffee with 1 tbsp of cream? I need energy, not to just wake up (have 2 small children) but also workout! 😀

    Best,
    Tanya

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Hi Tanya,

      Thanks for your question, and I’m glad you like the website :-).

      Okay, first I have a question for YOU: why would you want to eat walnuts? It’s not really a fast if you’re eating!!! Beyond this, the calories from walnuts are mostly fat and protein, and this won’t do much to give you energy. I would always advise people to work out in the morning on an empty stomach if possible. Yes, if you’re addicted to sugars and you require sugars to give you energy, you’ll feel really low on energy at first. Otherwise, morning workouts on an empty stomach (ie your last meal was the night before) force you to burn fat more efficiently. You’ll be able to get up in the morning without having to really on immediate food for fuel. This isn’t just better for exercise, it’s also better for life!

      If you absolutely need an external source to provide energy, then I’d opt for the coffee or tea. Caffeine can easily become an addiction too, but metabolically speaking it does less damage to you than sugar addiction. I have three kids too, so I understand where you’re coming from in terms of the need to get up and go. On the occasions when I need a morning pick-up, I ALWAYS turn to caffeine rather than calories for this reason.

      Hope this helps,
      Tallis

      1. Hi Tallis,

        Appreciate your quick response.

        Now that you stated the obvious, I feel darn silly! I guess it is out of an old habit of drinking my morning tea with some food and I read somewhere that walnuts help with satiety, so it felt like a healthier option. And is it true that if you keep calories under 100, it will not affect the benefits of fasting?

        Thank you,
        Tanya

        1. Tallis Barker, Ph.D. Avatar
          Tallis Barker, Ph.D.

          No need to feel silly – it just shows how strongly ALL of us are influenced by habits!

          As far as keeping calories under 100 goes, it depends what you mean by ‘benefits’. In terms of ketosis, even if the 100 calories were pure sugar, it wouldn’t significantly affect fasting ketosis (although more than 100 calories does impact on those clients measuring their ketones). In terms of your digestive system, it IS important to allow it to rest during a fast, and any calories are going to stimulate digestive juices. In terms of facing habits and addictions, well… I think we’ve already covered that. ANY calories – and to an extent even any tastes – allow your ego to get away with avoiding the issue!
          Tallis

          1. Thank you Tallis – you are the best!

            You made me think about ‘ego’ and we do make excuses but I also believe in working with one’s limitations – I will give up my morning tea for the days I fast (even if its intermittent). Instead I will have a green shot (homemade, no sugar added) or a small cup of warm water with 1/2 squeezed lemon….i guess it will stimulate the digestive juices (?) but Im OK for now with that. Its easier to drink the lemon/green juice quickly, brush my teeth and get on with my day…and then break the fast latter.

            Thank you again for all your kind advice.

            Regards,
            Tanya

            1. Tallis Barker, Ph.D. Avatar
              Tallis Barker, Ph.D.

              Hi Tanya,

              That sounds like a good plan to me. Yes, a lemon or green shot is going to stimulate digestive juices to a degree, but the 10 calories in half a lemon is pretty minimal. And any fruit requires only minimal digestive energy to break down.
              Tallis

      2. Jeffrey L Baker Avatar
        Jeffrey L Baker

        You mentioned in your article that before you start your fast you should somehow rid your digestive system of all of the food that you can. And I’m curious on how to do that. Normally I just start fasting and then after the fast. My body rids itself of whatever was in my digestive system when it went to sleep. I also have a very difficult time with diarrhea when I am breaking my fast I can’t seem to find anything to slowly eat to give my digestive system the kick-start it needs to not give me diarrhea. Great article thank you so much!

        1. Tallis Barker, Ph.D. Avatar
          Tallis Barker, Ph.D.

          Hi Jeffrey,

          Thanks for writing. The diarrhea you mention is probably related to the fact that you don’t adjust your diet before your fasts. In other words, your body is trying to get rid of old, undigested food as quickly as it can!

          Next time I would taper both the amount you eat as well as reduce the content of what you eat to only fruits and vegetables over the last couple of days (depending on the length of the fast). After the fast, I would also try eating a little less over the first few days of refeeding: again focussing on easily digestible fruits and vegetables.

          Hope this helps!
          Tallis

  7. Tallis can i still work when i am doing my seven day water fast ? Thank you Sir.

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Hi Franco,
      You may find you’re able to work if you have to, so long as your job doesn’t involve much physical labour. But it would be MUCH better to be able to take at least some of the 7 days off, so you can make the most of your fast and slow down!
      Tallis

  8. Just wanted to share with those who love to fast you can keep track of long fast and short fast the app is called MYFAST thier is a graph for your progress , your water intake , and notes plus you can keep track of weight loss its for android phones i PERSONALLY think its a great and easy app to use .

  9. Franco Catucci Avatar

    Evening Mr. Tallis, well i bit off more than i could chew on my first 7- to 14 day water fast . I lasted on my water fast 3 days 72 hrs. I kept a jounal of my fasg for these 3 days I learned a lot about myself. Mr. Tallis, how often could i practice a 3 day water fast till it just becomes natural to me ?? Could I do a 3 day water once a week ???
    Thank You Mr. Tallis for your comments!

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Hi Franco,

      72 hours is good! And I’m glad you kept a journal. This is good both as a point of reference on future fasts as well as helping to preserve your feelings.

      To answer your question: there’s no fixed limit about how often you might practise a 3-day water fast. I think you have the right approach here, though: to focus on 3 days until it becomes natural, and only afterwards start to consider longer fasts. This will making everything about fasting more manageable, more positive, easier, and therefore something you’ll want to keep doing in the long term too! This is the most important thing. Fasting should be for life!

      I’d suggest practising a 3-day fast whenever you feel an urge beginning to develop deep inside your body. This isn’t an intellectual decision – it’s something physical, felt in every cell of your body. If you don’t feel this bodily urge, then I’d suggest practising a 3-day fast at least twice a year, because this is approximately the minimum frequency in order to make ketosis something your body can easily access. Having said this, though, you might find that you feel the urge once every month or two. Or perhaps even more frequently. Who knows. Anything is possible, so long as you’re eating healthily in between and your weight is stable.

      I wish you success on your next fast,
      Tallis

      1. Franco Catucci Avatar

        Tallis , your awsome thank you for prompt reply your EXPERIENCES and information on water fasting is so inspirational. I feel in my body to water fast every weekend for a few months i am still going to eat ONE-MEAL-A-DAY the other 4 days when im not water fasting . I know water fasting cant hurt me i know its only going to help me .
        Thank you Mr. Tallis for sharing your information!

  10. Great read! I started 48 hour fasts two weeks ago. Currently, this is my third time and I’ve lost 12 lbs(and I have 10 more to go), but the strange thing is this time around, I don’t feel miserable at all. I hope to make it to 72 hours. That is what has lead me here: to see if fasting gets easier the longer one does it. Thank you for writing about this! I will check out your articles.

    The first week I fasted 48, then binged(Couldn’t help it), and then 48 and then more or less feasted frid/sat/sun. Pretty much, did the same the second week – except I didn’t binge/feast quite as badly. The weird thing is what I ate which was really bad and the results are still strong and I had very little rebound.

    All in all, with only 4 days of fast, I’m down and kept it off. I do drink teas/coffee. However, the teas are what really help with the hunger. I take vitamins everyday. I did cheat with unsweetened almond milk when I started to feel dizzy. I don’t think these kicked me out of ketosis though.

    Also, it does seem that I do switch back into ketosis pretty quickly. I have been playing with keto diet for the last 6 months or so. Is it strange to say that I think that after a carb up day, I can feel myself get back into ketosis within a day or so?

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Hi Jolie,
      Thanks for sharing. Your experiences sounds quite normal: that fasting becomes easier with practice – and as it becomes easier, there’s less tendency towards binge eating and “ping-ponging” afterwards. With more experience, I hope also you’ll find that you won’t need the crutch of teas, coffees, almond milk etc. This will allow a deeper dive both into fasting metabolism as well as the deepest insights into what water fasting has to offer. That’s okay. Everything will come in its own time…
      To answer your question, the more your body is tuned into ketosis (whether through regular fasting or a ketogenic diet), the easier and quicker it becomes to slip in and out of ketosis. If this is the case for you too, then a day or so sounds about right for getting back into ketosis. It’s about the same for me too.
      Hope this helps,
      Tallis

  11. Franco Catucci Avatar
    Franco Catucci

    hi Tallis , just wanted to share with you today 28 jul 18 6pm Saturday i started my 7 – 14 day water fast not for weight loss but for health reasons i been for the last 70 days eating ONE-MEAL-A-DAY omad 23 – 1 i have lost a lot of weight eating once aday thats my LIFESTYLE of eating and when i break my fast ill go right back to eating once a day
    When i break my fast i will break it with unsweetened orange juice avocado and cook vegetables and probably eat like this for a couple of days if you can give me more advice that would be great thank you for you support and encouragement advice you friend franco catucci .
    God Bless ❤👍🙏

    1. Tallis Barker, Ph.D. Avatar
      Tallis Barker, Ph.D.

      Good luck with your fast Franco 🙂

      1. Franco Catucci Avatar
        Franco Catucci

        Tallis can you please send me an Email an article on breaking any lenth of a water fast weather it a 3 day 7 day 14 day 21 day 30 day or a 40 day water fast ??
        Thank you Mr. Tallis .

        1. Tallis Barker, Ph.D. Avatar
          Tallis Barker, Ph.D.

          Sorry Franco, I don’t have any articles already written on the subject. However, my PDF on “How to Plan, Prepare and Practise a 3-day water fast” (link here: https://waterfasting.org/fasting-plans-shop/) does include a section about this. If you need a consultation, I also offer online coaching. Otherwise, the main thing is not to force the transition back to everyday eating!
          Tallis

  12. Franco Catucci Avatar
    Franco Catucci

    HELLO TALLIS, I APPRECIATE THE BACK AND FORTH Q & A ! I WANT TO TO START THE NEW YEAR 2019 WITH A 21 DAY WATER FAST 1- 21 JAN 19 NOT SO MUCH TO LOOSE WEIGHT BUT FOR MY HEALTH AND TO HEAL MY BODY FROM PSORIATIC ARTHRITIS I TAKE 2 INJECTIONS A MONTH ( HUMIRA ) to control symptoms MAYBE A 21 DAY WATER FAST WILL HELP ! WHAT YOU THINK ? THANK YOU FOR YOUR THOUGHTS ON THIS MATTER 👍

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