Dry fasting: fact and fiction

Article sections:
I. Introduction
II. Understanding the misunderstanding around dry fasting
IV. Is dry fasting safe?
V. Dangers of dry fasting

I. Introduction

If you tell someone that you’re doing a dry fast – that is, a fast in which you fully abstain from eating and drinking – they’re liable to think you’re crazy. That either you’re a crazy religious fanatic. Or that you’re just crazy-crazy, with a tendency towards suicide. Over the years, I’ve had several clients who were referred to a psychologist simply because a relative found out they were water fasting to heal chronic health issues. Imagine what would have happened if they’d spoken instead about dry fasting… Here in the modern world, we’re conditioned to believe that fasting without water is plain and simple stupid, if not dangerous. How could it have any health benefits?

Before having actually tried dry fasting myself, I would surely have said the same thing.

II. Understanding the misunderstanding around dry fasting

Like everyone else, I grew up passively absorbing society’s message about hydration: that you need to drink lots in order to stay healthy. This message implicitly suggests that the opposite – not drinking – is unhealthy. In this sense, dry fasting seemingly represents the polar opposite of health: illness and, ultimately, death. In fact, according to one urban myth you’ll die within three days if you don’t drink.

I’ve been regularly dry fasting now for several years, and I’m still alive. This, despite having practised dry fasts of up to five days…


Looking back on things, I too had formed a judgement not based on knowledge and experience but upon ignorance and fear. This fear is ingrained at the very heart of our modern consumer society. Consume, consume, consume: this includes the ‘need’ to eat and drink almost constantly, as much as the ‘need’ to go shopping and travel on expensive holidays. Modern consumer society conditions us to believe that without these things we can’t be happy, that we’re not fully living. – Or, in the case of not eating and drinking, we’re actually in danger of illness and death.


It’s only by experiencing deep in your own body the power of a dry fast that you have a realistic chance to overhaul your beliefs about hydration and dehydration. It’s only by taking the proverbial ‘red pill’ of cinematic fame that you wake up to the knowledge that temporarily giving up food and drink isn’t going to kill you. By waking up, maybe you’ll even begin to question all the other things you believe you really do ‘need’. It’s one path towards freeing yourself from the Matrix, which, through consumer society, is slowly destroying our planet…


The biggest hurdle to accepting dry fasting comes from the completely logical idea that if you’re not drinking, how can you flush out toxins? In fact, it’s quite understandable to assume the opposite: that if you’re not drinking, any freed-up toxins will accumulate and poison you. However, the actual facts about dry fasting (discussed in the sections below) illustrate that your body is perfectly capable of excreting toxins throughout a dry fast.

Not all types of cleansing require large quantities of water

It’s true that hydration levels play a crucial role in allowing the kidneys to extract toxins and waste products from the blood, and, dissolved in water, excrete them as urine. Beyond this, though, toxins exit the body through several other pathways which are less dependent on water.

For instance, certain toxins are removed via the lungs along with carbon dioxide (which of course is itself a waste product) as well as through the skin. This is one reason why we have smelly breath and can experience a negative change in body odour when fasting.

The liver also removes toxins by secreting them into bile, which is then released into the GI tract. Of course, bile contains water, but the total amount of bile produced during a fast isn’t enough to significantly alter hydration levels.

Dry fasting accesses adequate water from the body

Almost unbelievably, the metabolism of dry fasting accesses enough water from within the body to enable the usual cleansing pathways to continue through the kidneys. This is evidenced by the fact that urination continues while dry fasting: something which feels like a small miracle when you experience it yourself! Indeed, if urination ceases during a dry fast, this is a sign that it is time to end the fast and rehydrate.

It seems counterintuitive that urination should continue during a dry fast, but there are several important reasons for this – both of which distinguish the dehydration of a dry fast from that which usually takes place in everyday life:

(1) Lack of digestion lowers the demand for fluids

In everyday life water is needed to aid digestion. When you stop eating during a fast, the body therefore demands fewer fluids for this purpose. People experienced in water fasting often note how their thirst decreases on Day 2 of their fast: after digestion is largely complete but before the onset of deeper detox (which often does catalyse thirst). For instance, on Day 2 of a water fast I usually find myself thirsty for less than half of what I would drink on a normal day.

(2) Fluids are drawn out and away from the tissues

During a dry fast the body slowly but steadily draws water out from the interstitial space between the cells. As a result, the pressure inside each cell becomes greater than the pressure outside (in the interstitial space).  Consequently, the fluid within each cell begins to leak out into the interstitial space, carrying with it cellular waste products and toxins which would otherwise remain locked within the cell. This is, in fact, one of the primary reasons that dry fasting is such a powerful modality for cleansing, as well as offering direct and unparalleled relief to anyone suffering from inflammatory issues.

This process of drawing water out from the tissues can continue for many days, which means that your kidneys access a steady if slow supply of water to flush toxins out of the body. This contrasts with most types of dehydration in everyday life, which occur because of either excessive sweating (heat) or diarrhea (illness). In both these cases, fluid is lost from the body through the skin or GI tract, thus denying the kidneys their requisite supply of water.

(3) Metabolic water

The other reason that dehydration during a dry fast should never have to reach dangerous levels is because of your body’s metabolism while fasting. In order to burn fat molecules, the body must first break them up into ketones. (Think of it like slicing up a sausage into individual slices.) This process frees up hydrogen atoms which then go on to bond with oxygen in the blood, forming H2O: in this case known as ‘metabolic water’.

Dr. Sergei Filonov, an expert in dry fasting, estimates that every day the body is able to produce over a liter of metabolised water this way.1 This quantity broadly agrees with my own experience while dry fasting (keeping in mind that, in addition to urination, water is also lost through the breath and skin).

Naturally, the deeper the ketosis, the greater the volume of metabolic water produced. The body knows this, and is undoubtedly one reason why dry fasting stimulates ketosis more strongly and quickly than even water fasting. The benefit of a high rate of metabolic water production is also why I often recommend (and also practise myself) using an introductory water fast immediately before a longer dry fast. Under these circumstances, ketosis is already well established at the beginning of the dry fast, which means that an ample supply of metabolic water can slow down the rate of dehydration. This allows the dry fast to continue for the longest possible time: something which is crucial for people fasting in order to heal chronic health issues.

Draining the swamp

While the phrase ‘draining the swamp’ has unfortunately taken on political connotations in recent years, it also perfectly describes one reason why dry fasting is so powerful – and even more so than water fasting. There inevitably exist certain tissues in the body which under normal conditions are not flushed out as efficiently as others. Toxins which find there way into these areas of ‘stagnant water’ thus tend to remain there. They also serve as an ideal breeding ground for pathogens, just as mosquitos tend to prefer the still water of swamps to a fast-flowing river. Through dry fasting, you ‘drain the swamp’ of toxins and pathogens, and also deny any harmful bacteria and viruses of the water they need to thrive.

IV. Is dry fasting safe?

So long as you don’t push yourself beyond your natural physical limits, there’s no reason why dry fasting shouldn’t be completely safe. Just think of animals. When they’re ill, injured or need to heal, they lose their appetite. They stop eating. And very often, they also stop drinking. Effectively, they undertake a dry fast until they heal.

This should be natural for us humans too, and the idea of dry fasting still exists in ancient cultures as a means of purification – both physically and spiritually. The problem is that here in modern life we’ve lost touch with our own bodies. Instead, we’ve become addicted to the drugs of modern medicine, which deals with hiding symptoms without addressing root causes of illness. For most people, it’s easier and more comfortable to pop a pill than stop eating and drinking for a few days. Of course, it’s also more profitable for Big Pharma as well…

Aren't they pretty?
Aren’t they pretty?

Unfortunately, most drugs are also poisons – which is precisely why it’s possible to overdose! Add to this the barrage of toxins we’re exposed in every aspect of modern life – the air we breathe, the water we drink, the food we eat, the chronic stress we experience – and it’s no wonder that the toxic load of an average person makes dry fasting difficult. It’s simply too powerful. Or, at the very least, it can catalyse powerful and uncomfortable detox symptoms. This is why I would always recommend that you first adapt to and feel comfortable with water fasting before trying anything longer than a 24-hour dry fast.

V. Danger signs of dry fasting

As mentioned above, dry fasting can be too powerful for anyone with a high toxic load. Assuming that this is not the case, though, there are two important danger signs (see below) which indicate that it is time to stop a dry fast.

Heart rate

The slow and steady drawing out of fluid from the tissues means that blood pressure drops. Beyond a certain point, this means that the heart must work harder to circulate the blood. The powerful cleansing which takes place during a dry fast also requires the heart to work harder. Although periods of tachycardia (an elevated heart rate) are completely normal during both water fasting and dry fasting, sustained tachycardia means that the dry fast should end. Here, ‘sustained’ is a relative term dependent on cardiac health. But even for someone with no history of heart problems, it is unwise to allow a heart rate of 100-120 beats per minute to continue for more than 24 hours. If the heart rate ever begins to exceed this tempo, the dry fast should end immediately.


If urination ceases, this is a clear sign of dehydration reaching a point which could eventually cause damage to the kidneys. During a dry fast, urination should take place approximately once every 6-8 hours, with at least 100-150ml (3-5 fl.oz.) of fluid excreted per occasion. If urine output falls significantly below this or stops altogether, the dry fast should end immediately. Specifically in the case of dry fasting, urine output is a better indication of dehydration than the colour of the urine, which can become dark and cloudy simply through detox (especially during the first one or two dry fasts).

Speaking from personal experience, there is no question that regular practice of dry fasting increases the ability to produce larger quantities of metabolic water. In the meantime, it’s important to respect the body’s signs and limit the length of your dry fast accordingly!

Five days

In general, and with practice, dry fasts of up to five days should be completely safe at home. This is supported by numerous studies.2 Anything longer should take place under medical supervision. I would argue, though, that a safer and equally effective method is to completely avoid dry fasts longer than five days, and instead combine multiple periods of dry fasting (up to five days each) within an extended water fast. This is particularly effective in healing certain chronic health issues. Having devised this method a few years ago, I have since coached numerous clients to full health using this approach.



If you’re curious about dry fasting, I’d suggest putting aside your doubts and fears, and try it. After all, there’s only one way to find out! But do proceed cautiously, undertaking nothing more than a 24-36 hour dry fast at first. It’s important not to forget that dry fasting is literally the most powerful form of cleansing known to humankind.

1 Sergei Filonov, Dry Medical Fasting – Myth and Reality, 2008, ISBN 978-5-9900731-7-3

2 https://pubmed.ncbi.nlm.nih.gov/24434757/

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29 responses to “Dry fasting: fact and fiction”

  1. Another woman with fibroids here! Desperate to have a lighter period.
    I have successfully done a couple water fasts, and I’m willing to try the shorter dry fasts, but have a couple questions I’m hoping you can answer:

    1) Hair thinning. Am I going to lose my hair?
    2) I’ve been bleeding continuously. Today is the 36th day. It’s been a nightmare. Working with natural doctor who has me on bioidentical progesterone cream and some supplements, including iodine. I have no problem discontinuing the supplements, but what about the progesterone cream? I’m not ingesting it but it is an transdermal drug nonetheless. Also, am I allowed to fast while bleeding? If not, I may never get to try again because I have no idea when I’ll stop bleeding. And who knows if I stop bleeding and start fasting only to start bleeding again? Hope I’m making sense.

    Thank you for being a wonderful help and resource to all of us!

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

      Hi El,
      Thanks for sharing. It sounds like a lot is going on in your body, and to that extent I’d suggest setting up a consultation to discuss the specifics of your case. What I can say here more generally is that:
      (1) the metabolism of fasting can cause hair to thin, but in the majority of cases it tends to grow back thicker than before
      (2) extended fasting tends to bring irregularities in the menstrual cycle back towards a ‘middle ground’, but given that this is dependent on overall hormonal recalibration, it’s important to take the long view rather than expecting overnight miracles. You also need to be very careful in the use of any hormonal supplements during an extended fast.
      Hope this helps,

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