Why Is My Dog's Appetite Changing?

For dog owners, any change to a pup's behavior can sound the alarms—but should it? One of the scariest changes for many dog owners is a change in their pet's appetite, which we all fear could be a sign of something more serious at play. When should worry about changes in a dog's appetite and when it something natural and nothing to worry about?

We spoke to Chewy.com's resident vet expert, Dr. Jennifer Coates, about what dog owners need to know about changes in their pet's appetite.

Black great Dane puppy eating on deck
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Why is my dog's appetite decreasing?

If your dog's appetite has suddenly decreased, you'll definitely want to take note.

According to Coates, decreased appetite is a common symptom seen with many different diseases, particularly those that directly involve or indirectly affect the gastrointestinal system (like liver or kidney disease, for example).

Sad looking beagle Dog with a chew bone
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Illness and disease aren't the only reasons that a dog might suddenly stop eating (or stop eating as much as usual). Coates says that pain from dental disease or other conditions that affect the mouth is another common reason for dogs to stop eating normally.

Finally, stress—such as a move or altered household routines—or a change in diet may also put dogs off their food.

What is dog anorexia?

If your dog stops eating (or stops eating enough), he may be diagnosed with anorexia. According to the American Kennel Club, "appetite loss in dogs is called anorexia. Partial anorexia refers to an animal that is eating some food, but not enough to keep him healthy, and complete anorexia refers to total appetite loss for around three days."

Obviously, anorexia in a dog is very different than in a human, since it's not tied to body image or control issues, the way the condition is in humans. The AKC reiterates that the most common causes of appetite loss in dogs are changes in environment, drug reactions, dental disease, pain, or nausea.

While appetite loss can have serious underlying causes, however, the AKC notes that, in some cases, a dog's decreased appetite might be a case of food aversion—or picky eating.

"Sometimes though, dogs are just picky," the organization writes. "Switching to a new diet can cause some dogs to turn up their noses, and others may turn down food if they are fed in a stressful situation, for example eating next to a food-aggressive dog."

Still, you'll want to see your vet to rule out other causes, just to be safe.

Why is my dog's appetite increasing?

While decreased appetite can be a sign that something major is wrong, the same is true of sudden increases in appetite. According to Coates, increased appetite can be seen with certain diseases like diabetes mellitus, thyroid disorders, Cushing's disease, and exocrine pancreatic deficiency.

Puppy eating
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Of course, that's not to say that things are definitely dire if your dog starts eating more than usual.

"Dogs may also eat more than normal if they have lost weight recently and/or had restricted access to food," Coates says. "A switch in diet to a low calorie or poor-quality food can result in dogs eating more volume than they have in the past."

When should I see my vet if my dog's appetite has changed?

While changes to appetite might seem small, they shouldn't be ignored. While dogs (like people!) can just have a weird day here and there, if the change persists, you'll want to consult your vet, just to be safe.

As the American Kennel Club notes, changes to food intake won't have immediate effects on your pet's health—dogs can go for several days without eating without suffering severe consequences—but that doesn't mean you want to delay the vet consultation.

Coates agrees and suggests giving it no more than 24-48 hours before calling the vet if your dog's appetite has noticeably changed.

Hungry Labrador
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"Any change in your dog's appetite that lasts for more than a day or two and/or is accompanied with other worrisome symptoms should be brought to your veterinarian's attention," Coates advises.