Fasting Dogs and Cats

Dr. Karen Becker (DVM) is the resident pet ‘expert’ on Dr. Joseph Mercola’s very popular alternative health site. She commented in a blog post recently that it’s very difficult to find information about therapeutic fasting for pets.  She’s right, of course.  If you go looking for information on how to fast your dog or cat, you will likely find nothing at all.  Dr. Becker apparently wanted to remedy that situation and seems on board with the concept. But unfortunately she only revealed her own lack of understanding and created more confusion by making these inaccurate statements:

“Therapeutic fasting involves sufficient nutrient intake to maintain vital tissues, organs and muscle, along with liver enzyme co-factors to help with fat breakdown and the release of toxins.  In contrast, starvation involves no nutrient intake and depletes all reserves in the body, at which point vital tissues begin to break down.”

Fasting does NOT involve “nutrient intake”

That’s quite the opposite of what fasting is. Fasting is abstaining from nutrient intake. When she uses the two words “therapeutic” and “fasting” together, it can ONLY mean abstaining from all food (including “nutrient intake”) for therapeutic reasons, or in response to illness.

In fact, I don’t even use the term “therapeutic fasting” much because it has been used by people who actually mean something other than fasting. When I want to talk about fasting that is done in response to symptoms, I simply say “extended” or “long-term” fasting. This just separates extended fasting from the routine abstinence from food for one day per week as practiced by many raw feeders. 

What fasting IS

So, to clarify, any method of feeding that involves the ingestion of nutrients is categorically NOT fasting at all and should not be called fasting. It’s just a therapeutically modified way of feeding.  Fasting is refraining from the intake of ALL nutrients except water.  It is only under these conditions that the body is able to divert all its available energy to cleansing and healing.

During a fast, STORED nutrients are used

All bodies reserve fuel!  It could not be the case that death would be the immediate consequence for any species in the wild temporarily unable to find food.  If that were the reality, there would be no mammalian life left on this planet.  Dogs particularly are set up for long periods of prey scarcity, since that’s the kind of environment they developed in.  Wolves have been observed going months without a kill and there are many documented cases of lost or abandoned domestic dogs living months without food.  Further, it cannot be refuted that a sick or injured dog cannot hunt and therefore cannot obtain food.  To fast when sick or injured is as natural to them as breathing.

How long can a dog fast?

A fast may continue until bodily reserves are used up.  In the case of most domestic dogs, that would take months, literally.  At the point when stored reserves are entirely used up and food is not partaken of, THEN starvation ensues.  Fasting is extremely beneficial. Starving is not! But remember — it is long weeks or months away. There is no danger of starvation for a fasting dog of even below normal weight. The two terms should not be confused, and they should not be used interchangeably, because they have completely different meanings.

Fasting or therapeutic feeding?

All this is not to say that the kind of “fasting” Dr. Becker is referring to — more accurately described as therapeutic FEEDING — cannot be helpful.  When long-term mis-feeding creates health problems in dogs, it constitutes removal of cause to feed very dilute foods closer to what is ideal for dogs (such as raw milk, vegetable or meat broth) for a 30 or 60 day period in order to give the body a leg up.  Many dog owners do this thinking this is the best way to respond to disease, and it does very often have a successful outcome.  

It can be argued, however, that although this kind of treatment fits with civilized humanity’s misguided belief that good “doctoring” or “nursing” involves spooning bland liquids into the afflicted, it does no favor to them.  In fact, such scant offerings only keep the stomach active and wanting more.  This is particularly true of dogs, who, when left to their natural devices, tend to eat large quantities of food followed by no eating at all for several days.  Feeding just enough to keep a dog hungry seems much more cruel than fasting. If the benefits of fasting are desired with as little discomfort as possible, it’s best to feed no food at all.

A ray of hope

I don’t know if Dr. Becker has caught on to the power of true fasting yet, but there are some individuals in the “holistic” veterinary community are giving us reason to hope that they may someday ‘get’ fasting. Recently Dogs Naturally Magazine published an article on fasting by Dr. Gerald Buchoff in which he uses my words to support fasting over light feeding and references the same 50-day fasts of Dr. Ogden that I started talking about 15 years ago. In his defense, this actually illustrates how devoid the accredited veterinary literature is of information about fasting dogs and cats. It certainly should give dog owners pause when vets have to rely on untrained lay people for information about the most powerful tool for HEALING known to humanity.

Dr. Ian Billinghurst seems to be setting himself apart in regard to fasting as well. I was told recently by a member of my subscription group that in a private consultation a few years back with him, he recommend that she fast her dog for 5 days.

Fasting is power granted to us by nature

It’s impossible to overstate the empowerment that the knowledge of fasting can endow to dog owners if they will but put it to use.  Fasting is the kindest, most compassionate, natural, painless, stress-free, cheapest, least invasive, most effective (by an incomparable measure) way to approach constructive sickness such as skin rashes or eruptions, ear inflammation, digestive issues (diarrhea or vomiting) and most others.

To fast or not to fast?

In the case of chronic or degenerative disease, fasting is always beneficial as well.  However, if no serious or debilitating symptom is present, a dog will most likely be able to heal comfortably just by having the diet optimized, without fasting.  If a dog has been habitually medicated over a long period of time, as many dogs are, the residues of these substances will be liberated back into the bloodstream during a fast and this can sometimes cause discomfort.  For this reason, some dogs will be more comfortable continuing to eat proper foods while they heal.  This makes detoxification more tolerable.  So although fasting is almost always the best way to approach illness, there are some situations where it’s not really necessary.  After a dog is healthy for a period of time but relapses into some acute symptom like flaky/itchy skin or ears, then fasting can be used comfortably.

Misplaced guilt and how to avoid it

The emotional toll of fasting a dog on the part of owners is always the primary factor in determining whether a fast can be administered, and how long it should go.  This is potentially much more limiting than either the dog’s reserves or how long it would take for a symptom to resolve itself.  Owners typically have a difficult time fasting their dogs.  Anyone who has missed a meal and felt the growly stomach, irritability and weakness, projects these negative feelings onto their dogs when food is withheld.  It is news to most people to realize that these feelings are not hunger, but the body attempting to heal itself from previous bad habits.  That’s why they are usually felt most severely in the morning following a particularly indulgent evening meal.  Anyone who has done an extended fast himself knows that since these feelings go away after the first couple days, they could not possibly be real hunger.  Real hunger only ensues when reserves are decreased to a normal level and the body genuinely needs re-fueling.

The little voice in your head …

In addition to gaining an understanding of what happens to the body physiologically during a fast, dog owners also need to do the serious work of changing how they talk to themselves.  Appropriate emotional responses require rational thinking, and often our thoughts about our dogs are not rational, to say the least.  In other words, people must learn to tell themselves things that will lend support, veracity and substance to their actions.  In the case of fasting a dog, owners need to repeatedly remind themselves that fasting is KIND and compassionate, much easier and stress-free than a visit to the vet and unlike said visit, EFFECTIVE and FREE.  You will find that if you do this, you will no longer be plagued by irrational guilt when fasting your dog.

Fasting is not dangerous

Despite all the fear and ignorance surrounding this topic, it should be realized that fasting is never dangerous unless a dog is already emaciated.  And before you decide your skinny dog fits in this category, you should look at some photos online of truly emaciated dogs so you can see how much reserve fuel even skinny dogs retain on their bodies.

Knowledge is power

It is hard to find truthful information about fasting dogs, but the good news is that fasting as it is applied to humans is almost entirely applicable to dogs.  There are plenty of great books about fasting and likely even some good websites.  The best two books I know of about fasting are by Dr. Herbert Shelton and Paul Bragg.  The more understanding a dog owner has of this very powerful healing tool and the more s/he is willing to put it into practice, the healthier his/her dogs will be.

Can cats be fasted?

There is a great deal of fear surrounding fasting cats as well. The difference is that an indeterminable percentage of it may be justified. Cats are so ill-suited to the consumption of fat that even the fat that is autolyzed from their bodies during a fast can overburden the liver. This would likely be a problem only in obese cats with compromised livers, but since we don’t know for sure, we must proceed conservatively.  A cat with a chronic disease has obviously been mis-fed.  So all that needs doing in a situation like that is to correct the dietary mistakes and wait for healing to occur.

Kittens should not be fasted before weaning but acute or constructive symptoms that afflict older kittens weaned onto commercial pet food tend to clear up quickly with fasting, and there is no risk since kittens are not typically overweight and have healthy organs. Cats are often inadvertently rewarded for vocalizing or doing other behaviors that signal to the owners that they want food. Sometimes they do this out of boredom, particularly if they are indoor cats, so it should not be assumed that it’s indicative of real hunger. Nevertheless it can be problematic enough to make the owners legitimately want to avoid fasting their cats.

What We Can Learn from the REAL Experts

Unfortunately, I’m not aware of a single conventionally educated animal health practitioner who isn’t entirely clueless about fasting.  The system that trains people to do this work seems completely owned and controlled by profiteers who have no interest in keeping dogs well.  So we have to look to those pioneers of the past who had more freedom to think critically within their fields and express their findings and results openly.  Dr. Herbert Shelton was one such ground breaker, a human health practitioner whose understanding of the power of the body to heal itself is unparalleled in modern history.  Following is a quote from Dr. Shelton about fasting animals:

“Biologists, physiologists and research workers of all kinds are very fond of animal experimentation. But all of these workers are in the habit of ignoring important parts of the regular activities of animals. For example, they ignore, never mention, in fact, the numerous instances of dogs and other animals having fasted ten, twenty or more days when they, have received internal injuries or a broken bone. That a sick animal refuses food is well known to all laymen, but physiologists and biologists seem to think that this fact is unworthy, even, of mentioning. Can we not learn from observing the normal and regular activities of animals living normal lives–must we assume that animals are capable of teaching us something only when under artificial conditions, and subjected to processes that they never encounter in the normal course of their existence?”

And this, from Dr. Donald Ogden, who understood fasting and fasted many animals in his veterinary practice in the 1940s and 1950s:

“Every practitioner who will give this meritorious function due concern will realize that ten to thirty days’ abstinence from all food except water is nothing monstrous. I have fasted dogs and cats for periods of time ranging from one to fifty days, depending upon the pathology with excellent results and amazing recoveries being effected”.

Did you get that?  Dr. Ogden fasted dogs and cats up to FIFTY (50) days and always saw excellent results.  While going that long in the current climate of fear about long term fasting isn’t even suggestible, but how long can we continue to ignore this kind of information?  Is the uncertainty or misplaced discomfort we might feel for not feeding our dogs for a given period of time worth disregarding the potentially HUGE payoff of disease reversal?  I say, NO. 

I have personally fasted for 18 days so I know firsthand how beneficial and powerful it is. Just after my long fast, I sat down and made a video about proper feeding and fasting for dogs and cats with the founder of the fasting clinic. If you are wanting more information about fasting pets and haven’t watched it yet, it may be helpful.  I have also fasted many dogs and cats for up to 11 consecutive days, always with improvement to varying degrees and often with complete resolution of the problem that motivated the fast.

How to get started

If fasting your pets is of interest to you, I highly recommend educating yourself on the subject first. People who have either researched the topic objectively or actually experienced fasting themselves are the ones who have the most success and feel the most comfortable with the process. To that end, I would encourage you to join our subscription membership group where you will have access to a great deal of information on this topic and many others, and the benefit of my personal guidance in our private Facebook community. We have a library full of exclusive content including book recommendations, the entire 2,600 page Life Science course which includes lessons on fasting, the full text of Dr. Ogden’s book (mentioned above), my weekly Q&A videos and a long document that lists the criteria you need to consider before fasting your animals. If this is your first visit here, you need to start with reading the e-book, of course. This will give you the foundation of knowledge you need to start building health in your dog or cat.

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23 thoughts on “Fasting Dogs and Cats”

  1. Stephanie Soros

    Hi, I have a 12yr old White Swiss Sheperd girl 40kg who has never needed to go to a vet. Just over a week ago her upper jaw lips were swollen, then I noticed a loose bag of fluid inside her neck. I took her to this mobile vet who said she has a temperature of 39.8 & said her temperature is high. She wouldn’t be able to give a quarter zone shot until temperature is 39. She gave her 2 other jabs (Dupleallin 1mg & Niramine 1mg) & some Curam Duo Forte & said if she wasn’t better in 3 days she wanted to see her again. The swelling in her lips seem to come & go quite quickly for a short time. So went back as there was no improvement her temperature had gone down a little to 39.5 gave her another jab of Duplecillian & different tabs of Iramine. I said maybe some anti inflammatory tabs would help & she said she could have 1 tab of what I’m on (Meloxicam 15mg). She then told me that in 2days she’ll be away for a month & I’d have to find someone else if Duchess didn’t get better & that the swelling in her neck could be cancer.
    The swelling is still coming & going down some but never fully, her breathing is heavy (like she maybe starting to struggle breathing, the swelling seems to be bit more solid now too. I’m scared of loosing my best friend, would fasting help or go to a different vet? Please help 🙏

    1. Hi Stephanie, I would definitely not expect a different vet to help, and that’s because they pretty much all see inflammation the same way — as something that needs to be stopped with drugs and remedies. In truth, it’s something that requires our cooperation. It resolves on its own as soon as the crisis (saturation of waste) is past. As I explained in the group conversation we were having, fasting allows this to happen most efficiently because it allows the body to direct it energy to healing rather than digestion. Food is work before it is fuel, and when the body has urgent tasks to attend to, it needs NEITHER work or fuel. There are precious few resources out there to give you support for this kind of approach, and I’m happy to say I offer one of them. I have a subscription community that I work very hard to educate and support, including creating weekly live Q&A videos (hundreds of those are now in our archives, available for viewing), doing interviews, writing articles, and moderating a private Facebook group personally. I hope you’ll consider joining. Here’s the link: Of course I highly recommend you read my book as well so you will understand the rationale behind fasting and proper feeding and why it works so well:

  2. laura Milander

    Hi Nora,

    I hope you can help me. My cat who was diagnosed with a tumor a month ago (internally & externally) but she has always had a good appetite and went to the bathroom normally. Until she ate a mouse that she found in my house. She coughed up a lot of hair, after that she became ill and vomited every time she ate or drank water. The vomiting has stopped and she is drinking water but won’t eat. She still moves around some but seems weak from not eating. She gets up to the bathroom to urinate but can not poop. I gave her a little bit of pumpkin and it made her poop a little but blood was present. the next day she did a small piece was produced (really dark colored-no blood) but nothing else after that. Should i continue with a fast or take her to the vet? I always felt the vets aren’t very helpful. Thank you!


    Thanks Nora, that makes complete sense. If you read David Sinclairs book “Lifespan” (about curing aging in humans), one of the laboratory experiments is two groups of sibling mice – one group fed every day, the other group fed only every second day. The second group were allowed to eat as much food as they liked, so not much difference in calories consumed as they pigged out when they were allowed to eat. But the second group of mice lived almost 50% longer than the first group. Its a great book, covers so many topics on how cells and epigenetics work, highly recommended!

  4. Andrea Schmidt

    Hey there. Thank you so much for this article. My cat has developed a tumor on her mammary gland and I will be having it removed next week.The vet is pretty sure that it is cancerous. I have done many fasts myself and cured foot tumors that I had. So now I am thinking to fast my cat and monitor her to see. I mean the vet said the cancer can spread very quickly so heres my thoughts she will have it spread and pass away very quickly so we might as well try the fasting. She actually used to fast with me before and I have found that she had much more energy and felt better and she was more happy. So I will be fasting her two days now and monitor .I know lots of people who fast their dogs and they have amazing results. Thanks for sharing this information. I will come back with some results.

  5. Susan Parker

    Hi Nora, do you see any risk in fasting an extremely overweight golden retriever that was intentionally overfed for years in a puppy mill. She’s a rescue and lived in a kennel her whole life. May have had dozens of pups. Probably 5(?).
    If not physiologically risky, could it be too much of a shock right away to change every aspect of her former lifestyle? Would you wait?
    Thank you.

    1. I would probably feed her properly for awhile before attempting a fast. Considering her obesity, feeding correctly for maybe as long as 4-5 months will allow her to cleanse a bit first so the fast won’t be uncomfortable. Sorry for the delay in responding. 🙂

  6. One thing to mention, dogs tend to scavenge for items when they are hungry/fasting. Things such as grass, acorns, scented soaps left in bathrooms at dog level, ant and cockroach baits placed at high levels dogs would not usually go when they are satiated, or go counter surfing, etc. IMPORTANT when fasting is to MONITOR the animal to make sure they are not eating things even more dangerous to them. Please add a comment of caution to those who fast their animals and then leave for work for the day with the animals fending for themselves. Thank you for your work and input!

  7. Thanks so much for this info.. I discovered your site accidentally while researching online and seeing your comment under Dr. Becker’s article. I too, was astounded by the ridiculous statements there. I’ve had my dogs and myself fasting for 36 hours, and was uncertain about extending it another half day or so for the dogs, as I’m going to do for my own. After reading your article, it’s extension for us all, and I look forward to further exploration of your site!

  8. Hi Nora,

    My wife and I are hoping to get your expertise. Our cat has been picking at his skin to the point that he has been causing bald spots. He is also itchy quite frequently and tends to groom himself a lot. Our vet does not think it is a food allergy based on the ingredients that are in the food that we give him. We were wondering if it would be safe to have him fast because we hope that would help to resolve the issue. We were hoping to ask you whether or not this is a good idea, and if it is, how we would go about this process. Any help would be greatly appreciated.

    Thanks for your time in reading this and we look forward to hearing from you,

    Dustin and Jessica

    1. I would change the diet before fasting, and most likely this will resolve the issue. So sorry to have missed your question earlier. I have a transition tip sheet that I can send if you are interested.

  9. lori benett

    Hello, I have been researching for information on fasting my pup. She has always had a very sensitive stomach when it comes to food. She turned 8 in Jan of 2018 and I believe I have tried every 5 star food ~ freeze dried, kibble and even home cooking. For no reason that I can come up with, she will come down with loose stools or diarrhea some days. Sadie is fed a freeze dried and canned food and had been doing excellent so I don’t know what has changed to bring on the very loose stools. Do you think fasting would be helpful for her. Any help will be truly appreciated

    1. I’m sorry for the delay responding to your question. I think a change of diet to the proper method I recommend would be better than plunging her in to a fast of any duration. Stools are predictably well formed and easy to deal with on mono feeding.

  10. Jen Brouwer

    Great article! I am looking for more information on fasting my obese cat. She has been transitioned from being fed a free feed of Blue bufflo hard food to a twice a day feeding of raw food. She has been on this for several months but has not lost any weight. I have personally been loosing weight and healing by extended fasting, which made me think of it for her. I am sure I can safely move her to only eating once a day. So 24 hr fast, what are your thoughts of doing this on a regular basis, then maybe adding in a 48hr once a week? Is it safe to me aggressive? Do you have any resource for fasting and weight loss in cats? Thanks for your help

    1. Unfortunately there’s not much info available on the topic of fasting cats. If the food you’re feeding is commercial, it likely has too much fat and that could be holding her back. I’d feed nothing but home prepped lean meats and bones (game hens) for awhile and see if that helps. If not, I would not fast an obese cat without blood work to make sure the liver’s not compromised.

  11. Thank you for this article. I’ve become very interested in the topic of fasting lately. I’ve read quite a bit about human fasting, in particular I have been following Dr. Jason Fung. One of the principle reasons for human fasting is to trigger the autophagy process. That is our body’s housecleaning system, and it seems to rev up when in a fasted state. Do dogs also utilize autophagy? I would assume so based on the positive results, but none of the articles I’ve read mention anything about it. We need a scientist to champion the cause of fasting dogs and do copious amounts of research on the subject!! 🙂

  12. Very interesting!! I know it humans it can help reset the immune system & has been beneficial to cancer pts receiving chemo (they called it intermittent fasting I believe). Dr Longo has great info out there on effects for humans. Wondering if it’s the same reason in dogs. Thank you! I never would have put the two together – but I’m interested now to see if this will help my pup w/chronic allergies when he has an acute infection from them.

  13. Thank you, Tina, so nice to hear from you! It is inspiring and gratifying to know that there are smart, independent thinkers out there!

  14. Nora – I rescued two puppies – my guess is about 9 months – their back teeth are exposed just a little. One is a labradoodle and the other is a terrier/shitzumix possibly. They were both very overweight and delightful to bring home. They have never been taught to walk on a leash, sit, stay, they are not house trained whatsoever. They have literally been all over the place and totally unable to control their emotions – they are jumping, barking, whining constantly. I am in the process of finding a good home for them but first I want to teach them some manners! I have had them for 3 days now and they have only been given water. They have had nothing to eat and you wouldn’t even know it. They are slimming down finally and they are so much more calm today and nap and play – nap and play. No jumping excessively, no barking anymore and lay in my lap like a little kitten. Thank you for teaching me about FASTING YOUR DOG!! I wouldn’t have been able to bear the thought of fasting these two pups but I can see how much it has helped their countenance and what a pleasure to be around!! I am excited to feed them on day 5 – it will their dinner as I teach them some life skills! (sit, stay, etc) THANK YOU THANK YOU!!!! YOU ARE THE BEST TEACHER EVER and I really do appreciate your experience. You are a life saver for my own little Jemma! THANKS

    1. Hi Judy,
      This is welcome information as I’ve always believed that feeding improvements, including fasting, could have a major influence on behavior issues. Can you update me on the progress of these two? Did you notice any more improvements in their behavior as you fed them properly and did you find homes for them? Thank you for posting!!

  15. Joy Eriksen

    This reminds me of James Herriot, the Yorkshire Vet from the 1930’s. He had a client’s dog that was very ill, (mostly related to diet) He fasted the dog for several days, and then slowly reintroduced food. Two weeks later the dog was completely well and fasting was the only treatment given.

    1. Apologies for the delayed reply, Joy. I’m familiar with James Herriot’s name but not his writings unfortunately. If you can tell me which of his works contained this story, I’d definitely like to read it. Thank you!

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