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Why Isn't My Dog Eating?

Dog Staring at Empty Food Bowl

The question nearly all dog owners have asked ourselves at one point or another.

"Dogs obviously can't communicate the reason they stopped eating to us," says Dr. Justin Shmalberg, "and then there's the fact that dogs are designed for extended fasting. Although they're very food-motivated, dogs can go some time without issues on no food as long as they're otherwise healthy."

When your pup won’t chow down

If a dog refuses to eat, it's usually a behavioral issue or a health-related problem. In the former case, there's some good news: Dogs whose appetite loss is related to behavior are still usually willing to eat some foods, especially new diets or treats. 

"Complete prolonged food refusal is rare without an underlying medical reason," says Dr. Shmalberg. Below are common behavioral reasons that might be behind the loss of appetite in dogs 

Behavioral reasons why your dog won’t eat

Your dog is picky

Dogs typically aren't born picky — they learn to be picky. This is most common in smaller dogs who've been offered a range of foods. Extra offerings can provide way more calories than owners realize so that a dog doesn't feel as hungry and may wait for something better to come along, which is why dogs who get table scraps tend to be pickier than those who don't. 

There’s something wrong with the food

What causes hunger strikes could come down to food quality or content. 

  • Food that's gone rancid
    Higher-fat diets are more prone to rancidity than lower-fat diets. Kibble, especially if it's stored outside, may develop mold that we can't see, but that dogs can sense.

  • Kibble with palatants 
    Palatants are coatings on the outside of extruded kibble that change the taste of food — some dogs like the added flavor, some don't.

  • High-fiber foods
    While not necessarily lower-quality, high-fiber foods tend to be less palatable to dogs than foods with a lower fiber content. Some weight-loss diets fall into this category.

  • Too many treats
    Treats are a pretty surefire way to make your dog pickier. "Dogs love novelty and when they get a ton of treats, of different types and flavors, they want the same thing from their food," says Dr. Shmalberg. Some standard-sized baked bones pack in 50 calories or more — that's 5 percent of the calories a 50-pound dog with an average activity level needs in a day. Add a few of those into the mix, and it's easy to see why a dog might turn down a meal.

  • Exposure to fresh, canned, or raw diets
    Dogs may refuse kibble after they've enjoyed fresh, canned, or raw foods — likely due to the aroma of the extra moisture and aroma that dogs really respond to. And these diets (especially raw) are often high in fat, which dogs also love. 

Your dog is sensing stress

New animals or people can be stressful to dogs, especially those who are older, routine-driven, or naturally shy. Dogs with new, permanent changes in the house (like a new pet or baby) usually go back to their usual eating habits after a week or two.

Health reasons why your dog won’t eat

According to Dr. Shmalberg, the complete refusal of any food (treats, meals, etc.) is less common but far more concerning. Here are some reasons it could be happening:

Dental problems 

When dental problems arise, a dog may reduce his food intake drastically. Dr. Shmalberg also points out that objects can get stuck in a dog's teeth. 

"I once saw a dog who had a stick lodged in his teeth that had been there for two weeks, and started to destroy the tissue on the roof of his mouth," he says. "The only symptom was that the dog stopped eating."

Foul odor, loose teeth, large amounts of calculus (colored, mineral-like material on the surface of the teeth) are the first signs something’s wrong.

Stress and Anxiety 

Separation anxiety, generalized anxiety, and aggression appear to override appetite in some pups. Talk to your vet or an animal behaviorist to see how quickly you can get it identified and sorted out.

Physical and Medical Conditions

Most prolonged cases of a complete mealtime refusal (anything that lasts more than three to five days) stem from a specific physical or medical condition, such as:

  • Injury to muscles, ligaments, or other soft tissue 
    Most common in young and middle-aged dogs, any of these can cause a temporary lack of appetite while the inflammation is at its peak.

  • Organ dysfunction
    Kidney disease, liver disease, heart failure, cancer and other conditions commonly seen in older dogs that change the blood concentrations of certain compounds can make an animal feel unwell, and more likely to stop eating.

  • Gastrointestinal (GI) conditions
    Foreign bodies or obstructions in the GI system, parasites, viral or bacterial infections, inflammatory bowel disease, food allergies, pancreatitis and stress colitis, to name a few, all affect digestion and appetite.

  • Food aversion
    Dogs are prone to food aversion, aka the association of food with a particular feeling or illness. Dr. Shmalberg likens this to being sick at a fast food restaurant: "It's unlikely you'll want to go back and eat there anytime soon."

Recent Vaccinations and New Medications

A visit to the vet can be stressful for your dog, which may cause a temporary loss of appetite. Same goes for the brief inflammatory response they often cause. Neither are anything to worry about, as dogs typically get right back on schedule.

If changes in eating coincide with a new medication, or if your dog stops eating for more than two days following a vaccination, either of those could be the culprit. Give your vet a call to discuss.


As they age, dogs may become less active and eat less to maintain their weight. This isn't concerning if they're still in good shape. (Remember, the suggested feeding amounts on food packages usually overestimate what normal dogs need.)

If a senior dog is otherwise healthy, cognitive changes could impact his eating schedule or frequency, too. That in mind, get in the habit of taking any senior pet in for routine checks.

How long can a dog go without eating?

Just how long can a dog go without eating, anyway? "Dogs are extremely good at being normal while not eating. Their wild ancestors evolved to eat huge meals all at once, and then eat nothing for a period," says Dr. Shmalberg. "Sled dogs in the off-season, as one example, can be fed just once a week in some cases and function normally."

In the case of your dog, however, it’s worth sounding the alarm bells after a couple days. That’s typically enough time for a dog to get past their picky eater syndrome and reveal any serious underlying issues.

Anorexia in dogs

If your dog isn't eating enough and you suspect an underlying condition, get them checked out ASAP. Here are some signals it's time for a vet visit (and potentially a new eating strategy):

  • If you notice weight loss; and especially if your dog unintentionally loses more than 5 percent of their weight.

  • If your dog is eating less than 75 percent of their normal amount of food.

  • If your dog doesn't eat for a week, even if otherwise they seem fine.

The Nom Nom R&D team is on the lookout for dogs that experience regular diarrhea to participate in their new GI microbiome study. Sound like someone in your house? See if your dog qualifies for this paid research study here.

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