When people ask me how long can a dog go without eating, it’s usually for one of two reasons. Either their dog is healthy but doesn’t eat as much as expected or the dog is sick and refusing food. I searched the internet to see what’s out there for people to find on their own. It was disappointing to see the same inaccurate answer from almost every source. Here’s the science-based truth…
A healthy dog can go for many days, even months, without eating as long as they start at a good weight, have access to water and good shelter. Sick dogs can also go for days (or weeks) without eating, depending on their particular health issue. However, sick dogs get better faster when they’re getting proper nutrition.
Dog Starvation Compared to Humans
What do we know about starvation in dogs? And how much weight can a dog lose before they die from not eating?
Scientific studies are limited, but in humans, an increased death rate occurs when they’ve lost 35-50% of their ideal body weight. Animal pathologists speculate the same parameters may also apply to dogs. (8)
That means a dog who is healthy at 50 pounds would be in danger of dying from starvation when they get down to about 33 pounds or less. A 20-pound dog might waste away to 13 pounds before they’re in grave danger of dying.
Should I Worry About Dog Not Eating for a Week?
You should be concerned about your dog not eating for 2 days or longer if that’s unusual for them. But some healthy dogs naturally eat sporadically and seem none the worse for it.
Literature from 1912 details a case of one unusual dog going for 117 days without food. They claimed the Scotch Collie, named “Oscar,” was in good spirits the entire time and regained all its weight with no problem after the experiment. (4)
However, the authors of the paper noted the other dogs in the experiment became debilitated much sooner than Oscar. Oscar’s breed, the Scotch Collie, is one bred to do herding work on farms. They’re known for their toughness and that probably helped him withstand starvation for nearly four months!
Another couple of early experiments had dogs living 60 days and 98 days with no food, but only water. (5,1)
Factors in How Long a Dog Can Survive Without Food
Some dogs seem to tolerate starvation better than others, as in the example above with “Oscar” doing better than other dogs without food for a long time.
Age may be a factor with very young and very old senior dogs being more vulnerable to the effects of starvation. We just don’t have much information on how age affects a dog’s ability to go without food. In one paper, death due to starvation was uncommon in dogs younger than six months old. (2)
Starting Body Conditon
This is a bit obvious, but a dog’s starting body condition influences their ability to go without eating for a long time. If a dog starts out at a normal or above normal weight, we’d expect them to be able to go without food longer than a dog who was already lean before starvation.
The activity level of a dog is a factor in starvation survival. A dog who is confined will need fewer calories than a dog who is free to walk around or one who is required to work.
Weather and Shelter
Environmental factors such as being kept outdoors in harsh weather seem to play into a dog’s ability to survive starvation. Researchers speculated that cold weather might be harder on a starving dog than hot weather. (2)
Access to Water
Dehydration from lack of water can be deadly to dogs. Dogs who have neither food nor water are expected to succumb sooner than a dog who only has to go without food. Dogs have been known to survive without food or water for 11 to 20 or more days. (2)
What Happens When a Dog Stops Eating for a Long Time?
Besides losing weight and becoming too skinny, starved dogs experience changes in some blood parameters. A 2013 study (9) found the following changes in starved dogs:
- Low albumin (a blood protein),
- Low platelets
- Decreased number of red blood cells
- Low blood calcium
- High BUN (blood waste product)
Another interesting finding is that dogs do not go into ketosis when they are fasting (starving) as humans do. (6)
During extreme starvation organs in the body are also affected. Some of the changes seen by pathologists (2) examining dogs who died from starvation include:
- Ulcers, bleeding and bruising of the stomach
- Wasting away of skin structures,
- Liver cell shrinkage
- Thyroid gland atrophy
How Long Should You Allow Your Dog to Go Without Eating?
Healthy dogs can survive a long time with zero food intake as long as they have shelter and water. However, dogs who choose to go without food are a different matter altogether.
It’s somewhat normal for dogs to skip a meal occasionally. But most healthy dogs will not refuse food for more than a few days unless they have some sort of illness.
Therefore, I recommend you take your previously healthy dog to the veterinarian if they haven’t eaten for 48 hours. Do not wait until your dog has not been eating for a week! You should go even sooner if they have other symptoms such as vomiting, diarrhea, lethargy, coughing, trouble breathing, etc.
For dogs who eat only intermittently, it’s time to get your vet involved when your dog has lost 10% or more of their starting body weight. That means if your dog started at 20 pounds, they would be down 10% when they reach 18 pounds.
This is not a hard and fast rule since there are so many variables. In practice, I get concerned when a small dog loses more than half a pound, a medium dog loses more than one pound and a large dog loses more than a couple of pounds from not eating.
Why Is My Dog Not Eating His Food But Will Eat Treats?
Even though dogs can survive for weeks without eating balanced dog food, it’s not exactly good for their health. A dog owner will often report that their dogs won’t eat dog food but will eat treats.
Vets often discover a dog who is a fussy eater has digestive pain from an upset stomach or some other health problem. It’s common for these dogs to eat treats but not their regular dog food.
Your vet might recommend a trial with a special easy-to-digest food plus or minus medications to soothe stomach pain. A safe and easy thing to try at home is switching gradually to dog food for sensitive stomachs.
The wet food version is easier to digest for some dogs. Try feeding three or four small meals each day instead of one or two larger meals.
My clients have had good luck giving their dogs slippery elm for an upset stomach. Slippery elm is a very gentle herb that forms a coating in the esophagus and stomach. It’s available as a liquid, pill or powder for dogs.
Dog is Not Eating But Is Drinking Water
It’s common for sick dogs to refuse food but still drink water. If this goes on for more than 48 hours, take him to see a veterinarian.
If your dog is not eating but is drinking, they’re not getting the electrolytes they’d normally get from food. Without sodium, potassium and other essential nutrients, a dog can still end up being dehydrated after a day or two.
How Long Can a Sick Dog Go Without Eating? (Cancer, Parvo, Etc.)
It depends on a lot of things, but I recommend my clients not let their sick dogs go more than 24 hours without any kind of nourishment.
The biggest concern is that many sick dogs who aren’t eating are also not drinking well. Not eating and not drinking leads to feeling worse pretty quickly.
A study of animals hospitalized for various illnesses found that those who received adequate nutrition recovered faster. (7) This is an argument for figuring out how to get some sort of food into your sick dog even if they don’t feel very hungry.
Wondering How to Force Feed a Dog Who Won’t Eat?
In the vet clinic, we make sure to treat nausea first, then offer a variety of different foods–dry food kibble, canned food, watered-down canned food, rotisserie chicken, chicken baby food, etc.
If this still doesn’t work, we may try syringe-feeding canned food that has been mixed with warm water.
You have to go very slowly if you try force-feeding your dog because he can inhale the food if you go too fast. Other dogs get so frustrated it ruins their appetite even more.
Dogs expected to have a prolonged period of decreased appetite can have a feeding tube placed to make feeding easier on them.
You can get a bunch of practical tips from my article about how to get a dog to eat when they don’t have a great appetite.
How to Get Your Dog to Eat When He Doesn’t Feel Like It
How Long Can a Dog With Cancer Go Without Food?
Not all dogs with cancer have a poor appetite, but it’s a pretty common symptom. Some dogs with cancer who are eating adequate amounts of food still lose a lot of weight.
Dogs with cancer sometimes develop a condition we call cachexia. Cachexia is a wasting away of body tissues due to the effects of cancer rather than just from not eating. In cachexia, dogs lose muscle and fat tissue at equal rates.
If you pile starvation from not eating on top of cachexia, dogs get very skinny very quickly. I’ve seen dogs with cancer cachexia deteriorate in a matter of a few days when they’re also not eating.
Cachexia is said to be the cause of death in about 20% of human cancer patients (3), but we don’t have any data on cachexia deaths in dogs. If your dog has cancer and is not eating or is eating less than he should be, taking action to increase his food intake could increase his quality of life and possibly the length of his life, too.
I’ve written about how to get an older dog to eat, so try some of the tips and tricks to get your dog with cancer to eat.
Feeding Dogs With Cancer
Since dogs don’t have a requirement for carbohydrates, you should concentrate on getting them to eat fats and proteins. Carbohydrates can make up 25% or less of their daily diet. A lower carbohydrate diet may slow down the growth of some cancer cells, too. (8)
Your vet can prescribe Hill’s n/d diet which has higher levels of protein and fat to help prevent cancer cachexia. Some over-the-counter diets with low carbohydrate levels with higher fat and protein levels and might work in the same way.
You’ll have to choose a canned food as there are very few if any, dry dog foods that have a low level of carbs. One brand of non-prescription low-carb canned dog food that’s been popular with my clients is the Nature’s Variety Instinct line of products.
Homemade lower carbohydrate food is a good option for dogs with decreased appetite due to cancer. One recipe my clients have used successfully comes from Dr. Demien Dressler. He wrote the book The Dog Cancer Survival Guide and provides lots of great info on caring for a dog with cancer, including diet recommendations.
One caution about cancer diets for dogs: introduce any low-carb food gradually over a week or more. The higher levels of fat and protein might irritate a dog with pancreatitis or a sensitive stomach.
Homemade Food for Dogs Who Are Not Eating
Homemade food works well for dogs with a decreased appetite. If you have the time and desire to make a balanced recipe from human food for your dog, make sure to follow a recipe that has enough vitamins and minerals to meet a dog’s needs.
A wonderful option is to get a recipe for homemade food from a veterinary nutritionist like the folks at BalanceIT.com. Recipes are free and you can make one yourself for healthy pets. Sick pets need a vet to assist in making the recipe.
You must buy a vitamin/mineral supplement from BalanceIT to make the recipe complete. It’s not that expensive, considering that fresh, homemade food can make a big difference to your dog’s quality of life.
I’ve had many sick patients who won’t eat anything other than homemade food. Most healthy dogs also prefer homemade food to kibble and even canned food. Dogs are so smart!
I feed my own dogs homemade food for part of their diet. I’ve noticed less vomiting while they eat homemade food. I suppose it’s because the food is more digestible than kibble.
The recipes and supplements from BalanceIT help me make sure my dogs get all the vitamins and minerals they need to thrive.
Their recipes are pretty simple, consisting of only a few easy-to-find ingredients like chicken, rice and broccoli. You can choose your meat, carbohydrate and vegetable using the free recipe software on the BalanceIT website.
- My advice as a veterinarian: healthy dogs can go for weeks to months without eating food as long as they have shelter and enough drinking water but it’s certainly not ideal for them to skip more than a couple of meals.
- Skipping an occasional meal is somewhat normal for dogs, but refusing food for more than 48 hours is cause for a trip to the vet.
- Sick dogs heal better and faster when they get proper nutrition.
- Dogs with cancer feel better longer when they’re getting enough food.
- A balanced recipe from a veterinary nutritionist might be a good option for a puppy, adult or senior dog who is a picky eater or has decreased appetite due to a medical condition.
- Falck: Beitr. Physiol., (Stuttgart), 1875. Quoted by Pashutin in Pathological Physiology, 1902.
- Gerdin, J. A., McDonough, S. P., Reisman, R., & Scarlett, J. (2016). Circumstances, descriptive characteristics, and pathologic findings in dogs suspected of starving. Veterinary pathology, 53(5), 1087-1094.
- Hemming, L., & Maher, D. (2005). Understanding cachexia and excessive weight loss in cancer. British Journal of Community Nursing, 10(11), 492-495.
- Howe, P. E., Mattill, H. A., & Hawk, P. B. (1912). Fasting studies: VI distribution of nitrogen during a fast of one hundred and seventeen days. Journal of Biological Chemistry, 11(2), 103-127.
- Kumagawa and Miura: Arch. f. Physiol. u. Anat. (physiol. AM.), p.431, 1898.
- Lemieux, G., & Plante, G. E. (1968). The effect of starvation in the normal dog including the Dalmatian coach hound. Metabolism, 17(7), 620-630.
- Molina, J., Hervera, M., Manzanilla, E. G., Torrente, C., & Villaverde, C. (2018). Evaluation of the prevalence and risk factors for undernutrition in hospitalized dogs. Frontiers in veterinary science, 5, 205.
- Ogilvie, G. K. (1998). Interventional nutrition for the cancer patient. Clinical techniques in small animal practice, 13(4), 224-231.
- Pointer, E., Reisman, R., Windham, R., & Murray, L. (2013). Starvation and the clinicopathologic abnormalities associated with starved dogs: a review of 152 cases. Journal of the American Animal Hospital Association, 49(2), 101-107.