How Long Can a Dog Go Without Eating? Guide to Dog Diet

Few health issues concern a dog owner more than when their furry friend will not eat. Like humans, dogs need to consume enough calories and essential nutrients each day to stay strong, healthy, and energetic. When your pup has no appetite and routinely turns down its dog food, it can signal that something is very wrong. 

How long can a dog go without eating? In most cases, after 3 to 5 days of not eating, your dog will develop obvious health issues, but that doesn’t mean you should wait that long to act. Paying attention to the symptoms may hint at what is wrong, and it’s important to know when to take your dog to the vet.

How Long Can a Dog Go Without Eating?

Dog laying next to a food bowl
There are several reasons why a dog may lose their appetite including temporary sickness, parasites, and terminal illnesses.

Several factors determine how long your dog can go without eating, but serious health issues tend to present themselves after the dog has not eaten in about 3 to 5 days.

While it’s certainly possible for a dog to survive beyond 5 days without food, it’s very unlikely that it will not suffer long-term health consequences if it has not eaten anything in over 5 days.

What Signs Should You Look Out For?

Besides the obvious fact that the dog is not touching its kibble, there are also some related signs to look out for.

We explain what these signs could mean in the next section, but the following are symptoms you should keep an eye out for, alongside a lack of appetite:

  • Vomiting – If your dog is vomiting or attempting to, it could be a sign of a more serious issue. Eventually, the dog will just wretch and drool because its stomach is empty. If this lasts beyond 6 hours, contact your veterinarian right away. 
  • Diarrhea – If your dog has had the runs and will not eat any food, it could be a sign of a fairly serious issue. While allergies and a mild stomach bug could cause your dog to display this behavior, you should report it to a veterinarian if it occurs alongside a lack of appetite for more than 24 hours. 

Diarrhea could be a sign of a serious problem, like a disease related to the digestive system, parasites, a trapped foreign body, and much more. Consider calling your veterinarian ahead of time, as they may ask you to bring in a fecal sample for testing.

  • Lethargy and Evidence of Physical Weakness – Obvious signs of fatigue are extremely common in dogs that do not eat. If these symptoms last for a few hours to one day, it could be that your dog is experiencing mild discomfort due to an allergy or bug. 

If your dog starts eating again in less than a day and is back to its energetic self, it’s probably nothing to be worried about. If the dog continues to appear sluggish and unwilling to eat after 24 hours, take your canine companion to a veterinarian right away.

At What Point Should Your Dog’s Lack of Appetite Concern You?

Dog laying on a bed
If your dog hasn’t eaten in 48 hours, you should take your dog to the vet immediately for an evaluation.

If you notice that your dog will not eat any of its food over a single day, the best thing to do is monitor the situation. If the dog’s appetite returns the next morning, continue to keep an eye on its eating habits for a week or so, but you don’t have to panic.

On the other hand, if more than 24 hours have elapsed and your dog has still not eaten anything or shown any signs of renewed appetite, you should immediately consult your veterinarian. If the dog is nearing 48 hours without eating, take it to see a veterinarian immediately. 

Refusal to eat may not seem that serious to us, as many people will have an odd day where they don’t feel very hungry, but it is more concerning when it occurs with dogs. 

For people, a temporary loss of appetite can result from a cold, upset stomach, or another mild and temporary issue. Given that dogs cannot communicate what’s wrong, seemingly insignificant symptoms can indicate a really serious health issue.

It’s important to have a veterinarian exam to get to the root of the problem, especially if the dog has not eaten for more than 24 hours.

Take Your Dog’s Typical Attitude Towards Food into Consideration

A sudden and drastic loss of appetite can signal something serious, especially if the dog also displays any of the other symptoms discussed above. If, for example, you have a dog that rushes to its bowl immediately after you fill it with food, but it suddenly will not go near its food bowl, this uncharacteristic behavior is important to note. 

It could be a less pressing concern if you have a dog that tends to take its time with its kibble anyway. In cases like this, a loss of appetite for a day might be less concerning than it would for a dog that always seems hungry.

In other words, remember to consider your dog’s usual behavior when assessing the situation. More pronounced changes are certainly more concerning than more subtle changes.

How Long Can Dogs Go Without Drinking Water?

Loss of appetite and a refusal to drink water tend to go hand in hand, so it’s worth quickly going over canine dehydration.

As with humans, not drinking water is a more pressing and dangerous issue than not eating food. Serious consequences can result if dogs don’t drink water for 48 to 72 hours.

If you notice your dog isn’t drinking, check for signs of dehydration and consult your veterinarian as soon as possible. 

The following are some of the most common and obvious signs of canine dehydration:

  • Loss of Skin Elasticity Pull lightly on the dog’s skin. If it doesn’t return to its original position immediately, your dog could be dehydrated.
  • Xerostomia – Xerostomia is the loss of moisture in the gums. Look for obvious dryness and thick, slimy saliva along the gumline.
  • Heavy Panting – Your dog will pant more than usual if they are dehydrated, even when at rest.
  • Dry Nose and Sunken Eyes – If the dehydration is severe, you can often see it in a dog’s face. Feel the nose and pay attention to its eyes.

Remember, in dogs, dehydration can become an incredibly serious issue very quickly. If your dog will not eat, make sure they are not dehydrated, as well.

What Should You Do if Your Dog Won’t Eat or Drink and They’re Already in Poor Health?

If your dog is already suffering from a serious health issue, starvation and dehydration can rapidly worsen its condition. 

Monitor your dog’s daily water and food intake, no matter what kind of health issues it has. If you notice a difference in its appetite, thirst, or both, bring your dog to see your veterinarian right away.

Why Is Your Dog Not Eating?

Dog at the vet's office
A vet can determine why your dog has lost its appetite and may be able to recommend treatment to remedy the situation.

Now that you know how long a dog can go without food and what to do about it, let’s discuss some of the common causes of a loss of appetite.

You should still visit a veterinarian if changes to your dog’s appetite are drastic or they persist beyond 24 hours, but it’s useful to familiarize yourself with some of the common causes.

Physical Causes for a Dog’s Loss of Appetite

  • Physical Pain – Since dogs can’t describe pain with words, they often express it through changes in their behavior. In many cases, dogs experiencing severe pain respond by not eating or drinking. The pain could be due to a recent wound or aggravating a pre-existing injury. Many senior dogs also stop eating from arthritis and joint pain.
  • Serious Health Issues –  Remember that a dog refusing to eat its food could also indicate a serious medical condition, such as cancer, diabetes, internal bleeding, or a digestive issue. 

You must bring your dog in if it has not eaten for 24 hours. With just about every serious canine health issue, the faster you identify it, the better the chances are that you can help your sick dog.

  • Severe and Chronic Allergies – In some cases, a serious allergic reaction can result in a loss of appetite. While all allergies can impact a dog’s appetite, food-related allergies are the most commonly associated with a refusal to eat.
  • Infections or Parasites – An ongoing loss of appetite can also indicate the presence of parasites or a serious infection. Again, this is why you must take your dog to see a veterinarian if they will not eat. A veterinarian will be able to perform a blood test to determine whether or not your dog is suffering from a parasitic infection.
  • Dental Disease – Decreased appetite can also indicate dental issues. When plaque and tartar build up on the teeth, bacteria can spread into the dog’s gum line, and the dog could begin to suffer from gingivitis. 

Not only can gingivitis inflame the gums and cause pain, but it can also spread into the jawbone, leading to very severe issues for your dog. If your dog will not eat, inspect its teeth. They might not be eating due to tooth pain when they chew. 

  • Recent Surgery – Nausea and a decreased appetite are common side effects of many types of surgery. Surgery is stressful and confusing for the dog, and in some cases, the anesthesia can also make your dog feel nauseous. 

If your dog doesn’t eat or drink for more than a day after surgery, it could be a sign of a more serious complication, and you should immediately let your veterinarian know.

Mental Conditions That Can Cause a Loss of Appetite

Several types of mental issues can prevent a dog from eating. Just like humans, dogs can suffer from depression and anxiety. If your dog will not eat or drink, it could be suffering from one of these mental health issues.

Anxiety-Related Appetite Issues in Dogs

Dogs with chronic anxiety often lose their appetites for extended periods. If your dog will not eat and exhibits any of the symptoms listed below, your dog may be suffering from severe anxiety:

  • Abnormal levels of aggression
  • Regular and persistent trembling and shaking
  • Irregular amounts of barking and other unexplained vocalizations
  • Growling regularly, especially when it seems difficult to find an explanation for it
  • Hiding and exhibiting other signs of shyness, such as running away from people
  • Tucking its tail between its legs
  • General panic or separation anxiety when taken outside of the house or if the owner is about to leave the house
  • Aversion to contact, especially if that behavior was rarely exhibited in the past

If you notice your dog will not eat and demonstrates any of the above symptoms, it might be worth discussing anxiety treatments with your veterinarian.

Depression-Related Appetite Issues in Dogs

Just as dogs can suffer from anxiety issues, they can also experience depression. In addition to a loss of appetite, a dog suffering from depression can exhibit one or more of the following symptoms:

  • Abnormal Lethargy – Sudden changes in energy levels alongside a loss of appetite could signify depression.
  • Insomnia and Abnormal Sleep Patterns – If your dog doesn’t eat and sleeps at odd hours, or not at all, it could have depression.
  • Lack of Enthusiasm – If you notice that your dog is less excited to see humans, other dogs, its toys, and other things that used to be met with enthusiasm, it may be suffering from depression.

As you would expect, it can be somewhat difficult to diagnose depression in a dog.

It’s important to consult with your veterinarian if you notice any significant and ongoing changes to the dog’s behavior, especially if these changes occur alongside a lack of appetite.

Could Your Dog Just Be a Picky Eater?

While your dog might just dislike its food, there’s a difference between a total refusal to eat and a dog that’s a fussy eater.

If you have recently switched your dog’s food to a new brand or flavor and notice that they will not eat, they might need some more time to get used to their new food. In some cases, you need to wait the dog out, as they will eat when they get hungry. 

This behavior is common when switching your dog to vet-recommended weight-loss dog food. These dog foods tend to be very plain and flavorless, especially when compared to traditional, high-calorie commercial dog foods.

If your dog is on a prescription diet and won’t eat the new food, you can add things to make it more appetizing. For example, add a small amount of unseasoned scrambled eggs to improve the taste. Slowly wean the dog off of the scrambled eggs, and over time, it will begin to eat the food on its own.

Of course, if you have not made any significant changes to what you feed your dog, but it has not eaten anything for more than a day, there’s a good chance that it’s suffering from one of the physical or mental health issues we discussed above.

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Jesse Hopping, CCDT

Jesse is a natural-born dog-lover certified dog trainer (CCDT), dog foster, and former volunteer at Richmond SPCA and surrounding dog shelters for over 10 years. Her pack includes a Bernedoodle and 3 Boston Terriers. She’s sipping caramel coffee and watching her pack play in the sun when she’s not writing blogs. Jesse has her Certified Dog Trainer designation from CATCH Canine Trainers Academy since 2018 and and majored in English from the University of Virginia.

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