Is Juice Fasting Really Fasting?

I feel uneasy about the inclusion of the intake of food under the term “fasting”. So for example people use the term “juice fast”. Bearing in mind that juice is just fruit that has been chewed by a machine instead of our teeth, there is no metabolic difference between having juice and many other diets.

I once had nothing but fruit for 2 years. Does this now mean I fasted for 2 years?

This viewpoint was supported by the fasting forum at St Petersburg Medical School during the 9th Slavic-Baltic forum on nutrition in St Petersburg where myself and several like minded medical professionals agreed that “fruit fast” or “juice fast” is a contradiction of terms. But we also found not a single medical diagnosis where there is not at least some benefit from fasting appropriately.

As a Medical practitioner I have researched fasting for about 30 years now, and did hunderds of thousands of blood tests before, during and after fasting. The bottom line: Fasting is the most powerful healing force, outsrtripping all medicines and surgery. Not INSTEAD of, however, as the orthodox professions do have spectacular successes.. (and failures of course!)… but let’s do this COMPLEMENTARY.

dr A. Kruger
The Fast Doctor

Posted on by The Fast Doctor

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21 Responses to Is Juice Fasting Really Fasting?

  1. Tom Coghill says:
    Tom Coghill

    Hi dr A. Kruger
    By the Bible juice fasting is not a fast as fasting is without water as it means to cover ones mouth meaning not even sound goes out. So water fasting does not even pass that definition as you cannot drink if your mouth is covered.
    I am sure fasting in many languages means water fasting. Our culture has come to define juice fasting a fasting with no food, only juice. A widening of the definition due to society value. In reality, it is a juice diet, and nutritional support in a hospital program. Some call it juice feasting.

    I am interested in what you have learned along the way. I am also looking for someone to poke holes in my fasting theory in “fasting research” on the front page. We are also designing juice diet protocol for specific disease condition if you are interested in collaboration.

    • The Fast Doctor says:
      The Fast Doctor

      Thanks Tom, I appreciate the feedback. I do fast “dry” myself, anything from 30 to 80 hours once a week, usually 40-50. But metabolically there is nothing wrong with taking water as your body produces water during a fast anyway: Fat is, after all, primarily Hydrogen (when you count atoms or elements) which combines with oxygen (which you breathe in). Your system can produce up to 2 litres of water per day this way. But in some hot climates this will not be enough, thus my advice remains to “listen to your body” and give it some liquid if need be.


      • Tom Coghill says:
        Tom Coghill

        Hi The Fast Doctor,
        How can the body produce H20. Is water a byproduct of fat catabolism??????
        How much fat would be needed to produce 2 liters of water. Are you a MD. ?

      • ERobinM says:

        Hello i ran across your site the other night which was informative as well.. and i am by no means a MD Lol i am a holistic healer only but i do say to anyone who asks.. pretty much the same thing..When doing ANY type of fasting etc always..”Listen to Your Body” that is the key.. =-} Nice To Meet You..

  2. The Fast Doctor says:
    The Fast Doctor

    Fat, dear Tom, consists of a chain (or ring) of Carbon atoms, each of which can bind to other atoms on 4 “corners”. They typically use 2 of these to bind to other Carbons, thus forming strings. This leaves 2 “corners” to be filled. If these are fully filled by Hydrogen, we call them “saturated”. If not, the Carbons typically use the redundant “corners” to make double bonds with their neighbours.. and we refer to them as “unsaturated”.

    When you add Oxygen to the equation, the Carbons form Carbon Dioxide (Which you breathe out) and the Hydrogens form Water.

    Two Hydrogens bind to one Oxygen. Since Hydrogen weighs only one atomic unit each and Oxygen 16, two grams of Hydrogen will bind with 16 grams of Oxygen to form 18 grams of Water.

    Carbon weighs aboout 12 units. Thus one carbon with 2 hydrogens weighs 14 units, and from this you can make water with a weight of 18. Theoretically you can “gain weight” by just breathing in Oxygen!

    Of course in practice it’s different.

    And yes, I am graduated in science and registered as a medical doctor in a few countries.


    • Tom Coghill says:
      Tom Coghill

      Body fat contains 10% water. That would explain why dry fasting does not damage the body.
      I doubt the human body has the capacity to produce H2O through molecular conversion out of air that is only 21% oxygen. Reduce that amount by absorption capacity, metabolism usage and with a low molecular density (compared to water), so low that the amount that could be produced would be very small… if the body could. But on the other side, I posted the story on a man in India who states he has live for years without water or food and was tested in a hospital for 15 days.

  3. The Fast Doctor says:
    The Fast Doctor

    Dear Tom, the percentage of oxygen in the air has nothing to do with the matter. The lung preferentially absorbs oxygen onto Haemoglobin and its concentration on arterial haemoglobin is typically between 97% and 100%.. we measure this many times in the emergency departments.

    “Metabolism usage” of oxygen is exactly where the water (and carbon dioxide) forms.

    There is NO doubt that the lipids are catabolized into carbon dioxide and water. And there is NO doubt that more than 99% of that oxygen comes from the air we breathe. The tine bit of water in the fat cells are just not adequate.. anyway, it is not readily available to the circulation.

    15 days on air I can believe. I saw the research of a medical colleague of mine from Siberia who did 12 days herself. And after the flood in New Orleans, an elderly man was found unconsciouos almost 30 days later..

    But one fact remains scientifically indisputable:The water needed in these circumstances comes primarily from the oxidation of fat, using the oxygen from the air we breathe.

    Thanks for an interesting discussion.


  4. keith101 says:

    Hi The Fast Doctor
    I find your debate with Tom, null.

    Lets go back to the basics and science of fasting, healing, and the “SPIRIT.”

    I see science as the way forward and would never mock it, but you guys think you know it all.

    Maby you can share your experience on your longest fast and how you felt?

    Was it a water fast?…Was it juice/veg?, maby you can share this so we can understand your debate of nothingness?…

    Blessings Keith.

  5. The Fast Doctor says:
    The Fast Doctor

    Dear Keith101, I am impressed that you have knowledge about what I think.. was not aware of telepathy reaching so far, and I was acutely unaware of the “fact” that I “know it all”. I was under the impression that every single day there are so many new things to learn, so many new insights that we are blessed to receive.

    Or did I misunderstand the term “you guys”?

    On your questions: I fast a minimum of 60 days per year, and then fasting is defined as the metabolism that sets in after all carbohydrates (Blood sugar and glycogen) have been used.. thus only starts at least 24 hours after the previous meal. I think the longest was only about 8 days, thus “connecting” two weekly fasts and that was done during active Military training.

    If you read my previous post(s) you’ll note that anything containing taste is by definition contrary to my definition of fasting so it’s either air only or air and pure water.

    I do not understand the last (capitalized) question as in most posts I have tried specifically to indicate that fasting is in my expereince the most powerful healing force available.. was I misunderstood?

    Thanks for the comments.


  6. Ron says:

    Dear Doctor, I believe Keith was only trying to say, that your information about air being converted to water by the body is, well unimportant. And frankly a waste of energy to write about it in any depth here.

    Whether this is actual science or theory, it seems to have little effect on fasting in general. Unless maybe you were contemplating a survival mission in some remote part of the world, with little or no food and water.

    We appreciate your brain, and knowledge therein, but you do come off as a little pompous. What at first seemed a point of interest and curiosity has gone much further than expected. And it seems to be ego driven at this point.

    Lets be friends, and find another subject we can “all” relate to, and understand. We could use a good doctor around here! Thanks, Ron

    • The Fast Doctor says:
      The Fast Doctor

      I FULLY agree with you Ron, thank you for reading my mind. It’s a pity things got side-tracked by a remark in the passing. Let’s concentrate on the positive, which your attitude is a great example of!


  7. Orion says:

    I find it quite interesting, actually. And a bit amusing to see the two gentlemen have their conversation.

    Besides, this is how science works. It attempts to isolate the smallest effects. Not always good when it comes to the responses of the human entity, but it’s still a step in the direction where we want science to go as far as fasting is concerned. If you tell science that you don’t care about the molecular effects of fasting, you’re telling it you don’t want it to study fasting as a whole.

    I’d say there’s more than enough threads on this site to allow this one site be dominated by molecular make-ups of fat and water cells. At least for a little while.

    Doctor Kruger, you say you do weekly dry fasts. What can you tell me about the effects of that on the liver? Because that’s where most of the water goes, correct?

    • The Fast Doctor says:
      The Fast Doctor

      Thanks for the positivity, dear Orion.

      Actually the bulk of water is in the cells of the body.

      The next biggest volume is around the cells, tissue fluid bathing the cells.

      The blood contains barely 2 liters of water (unless you count the water inside the blood cells themselves of course).

      Water moves freely between these compartments.
      The kidneys filter the blood, but can only eliminate rather small molecules, and these has to be water soluble. The first part of the kidney (Glomerulus) filters off up to 300 liters of water per day. The second part (Tubule) re-absorbs what you need.. usually all but about one litre.

      The liver actually process the larger molecules and in particularly those that are NOT water soluble. So no, Orion, that is not where most of the water goes.

      During a fast the metabolism becomes more fat-based, so the kidneys can actually “take a break”: I find them producing no urine for up to 3 days on a fast, particularly if you ensure toxins are leaving the body through other ports, such as sweat glands.

      But what I try to squeeze into one post here actually needs a few hundred pages…


  8. mxxm says:

    I have been reading the posts of the “Fast Doctor” and have honestly NOT benefited from one thing he has said. Tom might not be a medical doctor but what he shares is revelant to the purpose of this website and helpful to its members.

  9. Tom Coghill says:
    Tom Coghill

    You own the site correct?

    I was totally impressed by the info, style and layout. is custom coded with a wordpress base code with thousand of hours of coding to get to this point. Basically said, we worked our ass off to get to this point where we can give free support to lots of people.

    You are clearly working at promoting fasting and I would love to support you in your work.
    I am serious about fasting and post treatment protocols for specific disease conditions. I also need to have credible science that backs up these protocols for testing in hospitals and “many” have shown interest after the success at our local hospital.

    Our “network” traffic runs close to 5 million a year. We are preparing to set up a program in Papua New Guinea through a congressman who fasted on this site, with one cancer patient already in treatment. I have a cured 83 year old cancer patient that looks at me in the eye weekly and says ” Tom how long, people are dieing.”

    My best fiend in India owns several cable TV stations and is waiting for fasting video. We have a 4 man team here at the house. We work as fast as we can as long as we can. It can take a day just to catch up on my emails.

    Andre, I know you are smart. Can you help and can I help you? Can we do something of significance, that is a gift to those who so desperately need it. I do not know if you feel the weight that I have on my shoulders. Lives are at stake and the longer we take, the more people die.

    I watched a 19 year old girl die of cancer, on a failed juice fasting treatment. It took a month to recover emotionally.
    And that was after watching 8 terminal cancer deaths.

    I stand here with all humility and a profound sense of inadequacy seeing a vision that will change the frontier of modern medicine.

    • The Fast Doctor says:
      The Fast Doctor

      Thank you SO much for this kind invitation, Tom, this is really appreciated. I have dedicated my life to this and would embrace any opportunity to give more people this gift of abundant health.

      Wherever I can possibly help, I’ll do whatever it takes to share your burden. When you get to my age you would have seen even more of this kind of suffering and it’s the stuff nightmares are made of.

      YES, Tom, let’s take hands and pursue this to its ultimate destination!


    • The Fast Doctor says:
      The Fast Doctor

      No Tom, is David’s property, I have only volunteered my time to consult on the site.

      My little place’s website is

      • Tom Coghill says:
        Tom Coghill

        Wow Andre,
        That is quite a place. Huge. You can put up a ad for it on the retreat area. Just make a post, upload pics and pick retreats for a category. How did you end up in Africa?

        • The Fast Doctor says:
          The Fast Doctor

          Well Tom my first German ancestor arrived in Africa in 1658, and the first French one in 1820.. but according to my genome I have more relatives in Iceland, my mother originated in Ethiopia (like apparently all females of modern man) and some ancestors were trapped in Iberia during the last ice age.

          Thank you for the invite re an ad, we would appreciate the opportunity to “cross-pollinate”..

          Drifting off the topic but interesting nonetheless..


  10. SecondChance says:

    Tom…..I have a 4 year degree in Aviation Material Science and am now going back to school for Nursing. In Microbiology we learned about the bodies ability to make it’s own water at the cellular level. The term used my Prof. was “Metabolic Water”…..I have also had to take a lot of Chemistry and Physiology class’s and the process that Mr. Andre or Dr. Andre is talking about is very real and well discussed at the University level in many different medical based class’s.

    Also not that baring sever labor in arid hot environment many texts say that a human eating a typical omnivore diet not fasting mind you get’s all the water they need from the food they eat as all animal and plant foods are made up of water to varying degree’s!SO your average office worker that sits all day in an air conditioned office driving in an air conditioned car etc…….Could eat a normal diet and drink nothing besides coffee for instance and never suffer from dehydration. Workers in Steel Mills in America drank coffee for their entire 8,12,16 hour shift non-stop they believed that drinking hot coffee would keep them sweating and would keep them alive. Coffee and Tea or caffeine containing beverages only act as a direct if you do not regular drink them. Regular use soon loses it’s direct effect. My point is that common repeated info is not always 100% CORRECT a lot of 1/2 truths and miss information in alternative health market. It so happens that their is not one single piece of research at the University level that can be found in all of America that can demonstrate the need for 8 8 once glass’s of water a day yet we hear it tossed about like it is a scientific fact!

    Right when you think you know the truth or something is a fact we often find out it is only 1/2 a truth!SO keep an open mind and challenge everything even what you think is true!

  11. The Fast Doctor says:
    The Fast Doctor

    True, SecondChance.. if fruit juice, for example, is considered fluid, then fruit is no different, as juice is only fruit that has been chewed by a machine instead of the teeth.

    I think it is important that we always consider the best source of information: “Biofeedback”.. IF we have not been taught to ignore the body and blindly follow tradition, then the body can “tell” us when we need what.