What to Do When Your Dog's Appetite Suddenly Changes

Analysis by Dr. Karen Shaw Becker

appetite changes in dogs

Story at-a-glance -

  • If you have a dog, mealtimes are generally happy times — unless your pet’s appetite suddenly changes
  • Knowing how to move forward when your dog’s appetite goes up or down depends on the underlying cause, which is why it’s important to make an appointment with your veterinarian
  • Dogs who become obsessed with food need to be seen by a veterinarian to rule out an underlying disease process that could be making them hungry all the time
  • There are many potential reasons for a decrease in appetite in dogs, so it’s very important that your veterinarian uncovers the root cause

Mealtime in most households with dogs tends to be a lot like celebrating Christmas twice a day, every day. The anticipatory joy usually begins a half-hour or so before the dinner bell rings, and dogs seem to have their own individual ways of showing their excitement leading up to the main event.

Some well-behaved pets go to their designated spot and sit or lie quietly as they've been taught to do. At the opposite end of that spectrum are the dogs who rudely counter-surf or leg-hump while their meal is being prepared. Others whine or cry or even howl, and some pups engage in exuberant play with a favorite pre-meal toy.

So, in other words, mealtime is typically a happy time for dogs and their humans — until it isn't. When your canine companion's appetite changes, either up or down, it's noteworthy. If the change lasts longer than a day or two, it becomes cause for concern.

Possible Cause for Concern: Your Dog Is Suddenly Food-Obsessed

Most healthy dogs are very good eaters and will typically overeat, given the chance. Your 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 evolved to view each meal as though it may be their last for a while. 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 meet his nutritional needs, 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 his food-seeking is a learned behavior, meaning you've reinforced it often enough that it's now a habit.

Tips for Dealing With a Perpetually Hungry Dog

  • Use her food obsession as a training tool — At least once a day hold short training sessions with your dog. She'll very likely learn new commands and tricks quickly once she realizes snacks are involved. Be sure to use very small portions of healthy treats, for example, frozen peas or tiny squares of cheese.
  • Be her food substitute — In other words, distract her as often as possible. Get in some playtime; take her for different types of walks, a ride in the car, or a trip to the dog park
  • Ignore the begging — Simply put, you must stop responding to her begging or she'll never stop begging; caving in is what created the behavior in the first place. In addition, you run the risk of making her overweight with too much food and/or treats.

Definite Cause for Concern: Your Dog's Appetite Decreases or Disappears

When your dog's appetite declines or disappears altogether, as an experienced pet parent, you immediately think, "This isn't good." And while there's no need to panic, you do need to begin carefully monitoring the situation. It could be he just has an upset stomach for some reason that resolves in time for his next meal. But if he continues to show a lack of interest 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

  • 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
  • Anorexia — complete lack of food intake (there's no such thing as partial anorexia)

Sharing with your veterinarian as many details as possible about your dog's regular eating habits and sudden lack of appetite will be helpful as the two of you work to determine the root cause.

Why Your Dog's Reduced Appetite Needs Urgent Attention

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 encourage 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 creating 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.

Things That Can Trigger a 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. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

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

8. 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. 

There are many other potential reasons a pet stops eating, such as 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.

Is Your Dog's Diet Playing a Role?

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 optimal, 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.