Woman and dog leaning on a kitchen table

You might have heard of intermittent fasting while looking for the perfect diet for your dog.

This powerful diet is practiced by more and more dog parents, yet is filled with fears, misconceptions, and myths.

Read on for the basics of this extraordinary method, its realities, the science behind it, and why it’s important for your dog.

What I’ll cover here:

  • What is intermittent fasting?
  • Is there such a thing as intermittent fasting for dogs?
  • Should you even consider fasting for your dog?

What is intermittent fasting and why is it important?

Intermittent fasting is defined as periods of time going without food followed by periods of normal eating.

Yes, is that simple!

Fasting periods can be of as long as a few hours of the day, or certain days of the week, or even cycles of multiple days in a row.

While there’re different established strategies to efficiently intermittent fast, the hallmark of the method is its flexibility.

With no calorie counting, no forbidden foods, no weighting and measuring rations, it’s a realistic, inexpensive, and practical method.

Contrary to most diets, the focus is on when to eat instead of what to eat.

More importantly, scientists keep unveiling new health benefits afforded to dogs by fasting, as well as to other two, four, eight and plus legged animals.

Notice that fasting is NOT starvation.

One of the reasons people tend to shy away from fasting is that it’s often confused with starvation.

Starvation refers to extreme durations without food that cause chronic health problems because of nutrient deficiencies and can even lead to death.

Fasting, when done right, does not lead to malnutrition.

Is there such a thing as intermittent fasting for dogs?

To talk about fasting dogs in our modern society in which consumerism and overeating is the norm might sound like a joke.

Or it might feel like one is just following a trendy keyword made popular by celebrities posting it on social media as their go-to method to keep their bodies in shape.

And that's the last thing you want to find when you're trying to figure out, like many other pet parents, something as serious as the best way to feed your dog.

But fasting is not a fad. Scientists and pet parents alike are seeing how fasting can completely revamp the health of dogs.

Perhaps fasting dogs gives you the impression of something unnatural or extreme, but intermittent fasting is nothing new, it's been practiced for millennia and is more common that you might think.

Dog lying in bed with an alarm clock

Intermittent fasting: from Galen to Gallus.

Already in ancient Greece, the fathers of modern Western medicine were adepts of intermittent fasting, including Galen, its most influential exponent.

They knew fasting kept people healthier emotionally, mentally, and physically.

For them, “therapy” consisted in keeping the body and the mind healthy instead of treating them once they were already afflicted with disease.

Intermittent fasting was at the cornerstone of that view. It was practiced regularly and recommended to their patients as preventive treatment.

Plutarch, a Greek philosopher went on to say, “instead of medicine, fast for a day”.

These days, you will find the practice of intermittent fasting even in the most unexpected places.

You can, for instance, visit a modern-day house of beautiful Gallus domesticus females (a.k.a. 🐔 hens). 

There you’ll learn how quickly you can become used to the stench of hundreds of chickens living together in a crowed space. 

But more importantly, you’ll also learn how intermittent fasting is used in these places.

When egg production declines, they fast their hens until they lose around 30% of their body weight, which results in increased egg production upon refeeding, with the added benefit, for the hens, of extending their lifespan.

Intermittent fasting is nothing new. From fasting rituals historically incorporated by most religions and cultures to health and wellness magazines promoting it as the best weight loss system, fasting is an age-old yet up-to-date method practiced by a soaring number of people.

Should you fast your dog?

Mounting scientific research suggest that fasting dogs is not only sustainable and realistic, but also beneficial for preventing and improving a wide range of conditions in dogs, from obesity-related diseases to cancer and aging.

In fact, food restriction is the only method that has scientifically shown, in a robust and consistent way, to slow down the development of age-related diseases and extend the healthy years of dogs.

So even if not overweight or sick, your dog can still reap the benefits of intermittent fasting, improving her/his wellbeing and preventing chronic diseases.

It all started with pioneer studies with laboratory rats in the 1930’s demonstrating that reduction of the overall food intake by about 30% decreased the incidence of cancer and extended their lives.

A few years later, scientists tested alternate day fasting instead of constant low food amount. The lab animals again obtained the same benefits.

Since then, researchers keep learning about all the benefits of the method and how it works at the cellular and molecular level.

How much food does a dog need?

Going for some time without food is just natural. Almost every animal, including dogs and humans, have, for most of its history, struggled with food scarcity.

Still, just the thought of leaving their healthy dog without food for some hours can be a source of anxiety for some owners.

I used to feel the same way.

However, it’s now becoming clear that animals are well adapted to a “fast-and-feast” way of living. If periods without eating made us and other animals too weak to look for food, survival wouldn’t be possible.

What happens is the opposite, lack of food triggers an innate survival mechanism that makes the body and mind work better.

Evidence of this is the fact that most of the beneficial physiologic and cellular mechanisms triggered by fasting are conserved across species, from insects to humans.

However, these days, especially in the Western world, the normal eating pattern is three or more meals a day plus snacks for humans, and two to three meals plus constant treats for dogs.

We simply eat too much and too often. And we feed our dogs the same way.

This, from an evolutionary point of view, is completely aberrant.

We went from scarcity to overeating.

We’ve been conditioned, mainly by the marketing machines of big food companies, to overeat and overfeed.

The consequences today are higher incidences of obesity, diabetes, cancer, and other chronic diseases for all of us: humans and dogs.

Dog stealing food from kitchen counter

So, are you ready to fast your dog?

Not so fast! 

These are only the basics.

For most dogs, intermittent fasting is safe and beneficial. However, there’re a few situations where dogs should not be fasted.

Fasting is only for healthy adult dogs. It is dangerous to fast puppies, and pregnant, lactating, senior, geriatric and diabetic dogs, and small toy breeds that are prone to hypoglycemia.

So, before you start fasting your dog is crucial that you have a better understanding of potential side effects, and contraindications of fasting dogs.

You also want to have a basic idea of the different modalities of fasting dogs, how and why it works, and how it can positively transform your dog’s health.

I’ll cover all this and much more in future posts. So, stay tuned.

In the meantime, leave a comment and let me know if there's a specific subject related to fasting dogs that you would like me to discuss.


Intermittent fasting = periods of time going without food followed by periods of normal eating.

Fasting is the most robust method scientifically proven to extend the healthy years of dogs.

Fasting for dogs is convenient, inexpensive, and efficient.

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