Intermittent Fasting for Dogs and Humans: Live a Healthier Life Together

Depositphotos 58899645 l 2015

There are dozens and dozens of animal studies and human clinical trials that show intermittent fasting can be a positive health benefit to both you and your dog.

The digestive system is a complex system. It has the power to not only get rid of toxins – including parasites, viruses, bacteria and chemical toxins – but it remembers those toxins next time they come into the body and even knows to dispel them. HOWEVER, when our bodies get food every day, the system never has a chance to "catch up" and reset. It is constantly working to remove the bad stuff from the good stuff. This can cause issues in the body, including miscommunication where the body mistakes its own cells for invaders and begins to attack the body’s own healthy cells and tissues. This is an autoimmune disorder and can present itself in a variety of outward health issues. In addition, when the digestive system is constantly working to digest new food, build-up of harmful toxins, excess fat and other harmful bacteria can occur.

In dogs, these contribute to these common dog ailments:

  • Arthritis (especially linked to the auto-immune disorder)
  • Allergies (especially linked to the auto-immune disorder)
  • Liver disease
  • Cancer
  • Yeast overgrowth
  • Chronic Upset stomach, including diarrhea

In Humans, we see similar ailments including:

  • Arthritis (especially linked to the auto-immune disorder)
  • Allergies (especially linked to the auto-immune disorder)
  • Liver disease
  • Cancer
  • Diabetes
  • Irritable Bowel Syndrome (IBS)
Benefits to Your Dog

As you can see from above, a dog whose digestive system is not running at peak performance can have a lot of chronic issues. Fasting helps by increasing anti-bacterial function, immunity (through increased immunoglobulin levels), cancer-fighting (through increased killer cell activity, which targets tumour and virus-infected cells), and fight inflammation (through increased monocytes, which ingest infectious agents).

During fasting, stored fat is used as well, helping getting rid of any stubborn weight your dog may have. And waste products that the liver was not able to process and were therefore stored in the fat are finally released – this can include pesticides from vaccines and flea control!

In “A longitudinal study of the influence of lifetime food restriction on development of osteoarthritis in the canine elbow” published in 2009, clinical tests on Labrador Retrievers showed that restricting calories to 70 percent of the diet for a fast decreased arthritis in joints.

And, perhaps most important to all dog owners, fasting has shown in several studies on several different species, including canine, to lengthen lifespan. One study done by Mark Mattson and his team at the United States National Institute on Aging found that mice, when fed nothing every other day, had a “much longer” lifespan and were “a lot” healthier. It should be noted that the mice were allowed to eat as much as they wanted on the day they were given food, and they usually consumed about double what a mouse normally would.

Studies by the University of Columbia found that fasted rats recovered from spinal injuries quicker, with increased neuronal regeneration.

These are just a few examples of studies showing the benefits of fasting in animals.

Benefits For You

In humans, studies have shown that fasting causes the body to switch from using glucose stored in the liver for energy to ketones, which are stored in fat. According to the United States National Institute on Aging, the key here is not weight loss, but the increase of ketones in the bloodstream, which has some large positives including improving glucose regulation (think of those with diabetes!), removal or repair of damaged molecules, increased stress resistance (including improving body’s defences against oxidative and metabolic stress), and suppressed inflammation (including inflammation caused by osteoarthritis and IBS).

Human studies conducted by Salgin, Marcovercchio, Hill, Dunger and Fystyk (published 2012) found that a 24-hour fast increased growth hormones (HGH) as well. HGH are vital for growth, metabolism, weight-loss and muscle strength. Another study on men found fasting for two days increased HGH by 5 times the amount before the fast!

And, just like for dogs, fasting can help with arthritis pain, studies show. One study conduct by Andreas Michalsen for Charite University in Berlin, Germany (published February 2019), showed “Modified fasting (up to 500 kcal energy intake per day) for 7-10 days leads to an improvement of the symptoms in many patients with rheumatoid arthritis and is regularly used by the applicants for the treatment of rheumatoid arthritis.”

And while there are not currently any studies on fasting and aging on humans, the animal research shows that it can lengthen their lifespan, so it may just do the same for humans too!

Intermittent Fasting

Intermittent Fasting is the most common type researched. It involves lowering your food intake to none or a minimal amount for hours to days. The most common ratio used in research is fasting two days a week OR daily restricted feeding where you only eat during a six-hour window each day. These types of fasting can be used for both dogs and humans, so you could even put you and your dog on the same schedule!

Researchers have found even cutting your dogs food down by 70% for one day a week can be beneficial. Many people who fast their dogs give them a bone broth (such as chicken or beef stock) on fasting days, to make sure they get plenty of fluid (and let’s face it, to keep their dog from begging all day!).

Be sure you are doing a correct, interment fast, and not a “starvation diet.” Starvation occurs when the body does not get enough nutrients to function properly. After consuming fat reserves, the body will start to use the proteins within its own muscle tissues. You do not want this! However, a fast done correctly will not put you or your dog in any danger of starvation.


If you have any questions or concerns about your current health or your dog’s before beginning a fasting regime, talk to your doctor and/or veterinarian. Then, you may just decide to try a joint day of fasting where both human and canine let their systems flush and reset, so you can both live healthier, and maybe even longer, lives.

At Stay Loyal we recommend feeding healthy adult dogs one meal per day, six days per week. With one fast day which equates to 48 hours of no food and unlimited water. We also recommend feeding a nice juicy raw meaty bone twice a week, no kibble on these days. Try this with your dog and I am sure you will see an increase in vitality


Great article, thankyou Robert. Food for thought.
If you and your dog aren't eating anything on the intermittent fasting day, what's the difference between that and a starvation day?


Hi Linda, Starve day or fasting day are both the same, just different wording. "Intermittent fasting" is just the new softer terminology.


When is the BEST time of day to feed a dog, bearing in mind that if they are an indoor dog and need to get outside to poo at a reasonable time.
How long does it usually take between a meal being consumed and it being Eliminated from the other end?


Hi Andy, Good question. I guess the best time would be so the poo time coincides best with when you are home and able to let the dog out. The average is 12 hours but if you have an old dog or a dog with issues holding it then you need to work back from when they need to go. Say for example you currently feed at 7pm and find your dog is waking you because it needs to go at 2am. Id try moving the feeding time 5 hours earlier so the dog can go at 9pm. Or even try feeding in the morning. Another thing to take into consideration is exercise time. You should always want your dog empty when exercising. Feeding after exercise works best for dogs.


Excellent aritical. I have thought about fasting as a health benefit for myself over the last year or two, but have yet to take that step. Maybe I could do it with Reggie. I do need to read more on how to for me though, as I really don't know how to start etc. I was just going to not eat one day a week, but don't want to risk my health. My GP is pretty old school so not something I can do with his support. I think I need to find a support group or just online information about doing this safely. Including Reggie I think could be very beneficial for him too. Thank you for the info.

Tony Mac

Refreshing article from a dog food site. Have been fasting my working dogs, in this fashion , for over 40 years.
Definitely keeps them fresh and vigorous . There is a big difference between well nourished and over nourished .
Make sure the dogs have everything they need , but give their system time to recover and cleanse itself .
Thumbs Up !!

RobertTony Mac

Thanks Tony, you make a good point about the difference between nourished and over nourished. Fingers crossed more people learn the difference.

Miesha Collins

Just wondering if the fasting should be done for puppies? Mine is 7 months old. Is this too young to be fasting? She has 2 meals a day. Morning and night. Do I skip just 1 meal? Thanks

RobertMiesha Collins

Hi Miesha. Yes, skip one meal and that way you are getting into the routine early so that it is easier when your puppy becomes an adult.

Debra Anderson

Interesting article. I have been intermittent fasting for about 4 years but have never considered it for my dog. How can one fast day per week equate to 48hours? Is this a typo?

RobertDebra Anderson

Hi Debra, we recommend feeding once a day. So if you feed Saturday night and skip Sundays meal the next meal should be Monday night. This would be 48 hours of no food. Even if you feed twice a day skipping one meal a week (24hours) will still benefit your dog.


Such an interesting read. I have no trouble with fasting myself (have been doing it for years), it’s fasting her ladyship where my problem lies! The head resting on knee and the eyes ‘have u forgotten about my dinner?’.,I can’t bear it lol!


Hi Jackie, I know its hard at first but once you see the results its hard to look back.