Appetite in dogs — Too little or too much can spell trouble

Analysis by Dr. Karen Shaw Becker

inappetence in dogs

Story at-a-glance -

  • Healthy dogs are almost always good eaters, so a decrease in your pet’s appetite is often a sign of an underlying medical condition
  • Make an appointment with your veterinarian if your dog’s eating habits change, and make an urgent appointment if the change is very sudden or dramatic
  • There are many potential causes for inappetence in dogs, and it’s crucial that your veterinarian investigates the situation carefully
  • Treatment of a change in appetite depends on the underlying cause
  • Dogs preoccupied with food also need to be seen by a veterinarian to rule out an underlying disease process that could be making them ravenous

Since most healthy dogs are confirmed chowhounds, when a dog's appetite decreases or disappears, the universal reaction from experienced pet parents is, "Uh oh." And while there's no need to panic, you do need to begin carefully monitoring your dog's eating if it drops off.

He may just have an upset stomach for some reason that resolves in time for the next meal. But if he continues to show a disinterest in eating over a couple of days, it's time to investigate. When you bring your dog to his veterinary appointment, it will be very helpful if you've already determined which of the following three situations best describes his lack of appetite:1

  • Anorexia — complete lack of food intake (there's no such thing as partial anorexia)
  • Hyporexia — reduction in food intake, regardless of the reason or cause
  • Dysrexia — distortion of normal appetite or eating patterns, for example, a dog who refuses to eat his regular diet but will eat cooked chicken and rice

Sharing with your veterinarian as many details as possible about your dog's regular eating habits and sudden lack of appetite will be helpful in finding the root cause.

Why you can't ignore your dog's decreased appetite

In case I wasn't clear, if your dog refuses to eat for longer than a day or two, especially if there are other symptoms, or if there's a sudden noticeable reduction in her food intake, it's important to see your veterinarian right away. If the decrease is gradual, it's just as important to get her checked out, but it's not as urgent a situation as a sudden, dramatic change.

It will be your veterinarian's job to search carefully and thoroughly for the underlying cause of your pet's loss of interest in eating, because there's almost always a cause. Her appetite isn't going to improve if the problem isn't identified and addressed. It will be your job as your dog's advocate to prod your vet to keep looking.

It's also important to know that appetite stimulants (which were originally designed as antidepressants) prescribed by your veterinarian can be useful in the short term, but they don't address the underlying problem of inappetence. They may for a time successfully treat the symptom (refusal to eat), but not the cause.

When it comes to treating a dog who won't eat, there's no one-size-fits-all approach. Your veterinarian must do a thorough physical exam and diagnostic workup, and investigate metabolic changes such as hypertension, blood potassium levels, anemia or vomiting. He or she should also consider any medications or supplements your pet is taking to rule those out as a cause.

You'll also want to fill your vet in on any changes that have occurred in your dog's environment or daily routine that might be causing her stress. The cause of your dog's disinterest in eating will determine an appropriate treatment approach. If there's an underlying disorder that can be successfully treated or managed, her appetite should return to normal as the condition resolves.

8 potential causes of lack of appetite in dogs

In the vast majority of cases, when a dog loses interest in eating, it's a symptom of an underlying medical problem. Some potential triggers include:

1. Food aversion or pickiness — Food aversion can occur if you make a sudden change to your dog's diet. It's almost never a good idea to do this quickly because it can cause diarrhea. If you want or need to change the diet you're feeding, do it gradually by mixing the new food in with the old food in a slow transition.

Some dogs refuse to eat certain foods for reasons that may or may not make sense. And some are simply notoriously picky eaters who often require special menus or lots of coaxing.

2. Stress — If your dog is feeling stressed for some reason, he may turn away from his food bowl. For example, some dogs don't have much appetite when they're in an unfamiliar place, their favorite human is away from home, or when there are other pets around at mealtime.

3. Dental or gum disease — Sometimes a problem in your pet's mouth can make eating a painful experience. This can be a broken or loose tooth, severe gum disease or an oral tumor.

4. Nausea — While relatively uncommon in dogs, nausea can certainly put your pet off her food. Unless there's an underlying illness, nausea most often accompanies car travel.

5. Illness — A dog who feels sick will often show little or no interest in eating. Sometimes it's just a passing gastrointestinal (GI) disturbance; other times it's much more serious, such as a systemic infection, liver or kidney disease or cancer.

6. Pain — A painful condition anywhere in the body, and especially in the GI tract or mouth, can cause your dog to eat less or refuse to eat.

7. Obtundation — This condition is a lack of alertness more pronounced than lethargy, and is usually the result of an underlying medical condition such as hypercalcemia, metabolic disease or trauma.

8. Recent vaccination — Loss of appetite can be an immediate adverse effect of vaccination.

Of course, there's a myriad of other potential reasons a pet stops eating: GI foreign bodies, exposure to or consumption of toxins and dozens more. Your veterinarian will recommend diagnostics based on your pet's physical exam findings.

Have you considered upgrading your dog's diet?

The diet you feed your dog plays a foundational role in both maintaining his interest in food and his health and overall vitality. As always, I recommend a nutritionally balanced, diverse, species-appropriate fresh food diet.

Over the years, I've known many dogs on processed diets who were considered fussy eaters, or who spent as much time playing with their food as eating it. When their owners gradually transitioned them from a kibble or feed-grade canned diet to raw or gently cooked fresh food, the weird eating habits disappeared.

If your dog gets a clean bill of health from your veterinarian but still isn't eating well, review the diet you're offering and see where it falls on my latest ranking of best-to-worst pet foods. Make upgrades as you're able to and see if your pet's appetite improves.

The opposite of inappetence: the always hungry dog

As I noted earlier, most healthy dogs are very good eaters and will even overeat, given the chance. The domestic dog's closest wild relative, the grey wolf, is adapted to a feast-or-famine diet, often going for long stretches without finding fresh prey. To survive, wolves eat large amounts of food when it's available, stash food for later and scavenge as necessary.

That's why dogs tend to eat whenever food is around — not necessarily because they're hungry at that moment, but because they're never entirely sure when they'll see their next meal. Sadly, it's also possible some adopted dogs harbor memories of starvation from earlier life experiences, and will forever view food as a rare and precious resource.

This is why it can be difficult to determine whether a food-obsessed dog is just following his natural instinct to eat at every opportunity, is driven by a fear of starvation, is being fed a diet that doesn't nourish him at the cellular level or has simply mastered the art of manipulating his humans for food and treats.

A less likely but potentially serious possibility is an underlying medical condition (e.g., diabetes, hyperthyroidism, Cushing's disease) that causes your dog to feel excessively hungry, no matter how much he eats.

I recommend making an appointment with your veterinarian if your dog seems to be extra-hungry even though he's eating well, and especially if he's also losing weight. If he gets a clean bill of health from your vet and he's eating right for his species, there's a good chance the food-seeking is a learned behavior, meaning you've reinforced it often enough that it's now a habit. Tips for dealing with an always-hungry dog:

  • Ignore the begging — You have to stop responding to his begging or he'll never stop begging. In addition, you run the risk of making him overweight with too much food and/or treats.
  • Use his food obsession to train him — At least once a day hold short training sessions with your dog. He'll very likely learn new commands and tricks quickly once he realizes snacks are involved. Be sure to use very small portions of healthy treats, for example, frozen peas or tiny squares of cheese.
  • Be his food substitute — In other words, distract him as often as possible. Get in some playtime; take him for a nice walk, a ride in the car or a trip to the dog park.