Loss of Appetite in Dogs

Courtesy Jackie of NomNomNow

Dogs love to eat. From the tiniest, most energetic puppies to distinguished four-legged seniors, they seem to gobble up pretty much anything you put in front of them – any time, anywhere. So when a dog won’t eat, it can feel pretty upsetting.

If you find yourself with a dog not eating, or a puppy not eating, it could be due to a number of factors – from health conditions to behavioural problems to the type of food you’re offering. But figuring out the exact reason why can be difficult. “Dogs obviously can’t communicate the reason they stopped eating to us,” says Dr. Justin Shmalberg, a Doctor of Veterinary Medicine and NomNomNow’s veterinary nutritionist, “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.”

Yet, to properly treat a dog’s loss of appetite, you have to know what’s causing it. That’s where we come in. We’ve put together a guide to the most common causes of hyporexia (reduced food intake) and anorexia (complete refusal of food) in dogs, and steps you can take – usually with the help of your vet – to get your best friend eating again:

Behavioural Reasons

Why won’t my dog eat? This is a question vets hear fairly often. If a dog refuses to eat, it’s usually either a behavioural issue or a health-related problem. In the former case, there’s some good news: dogs whose appetite loss is related to behaviour 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 behavioural reasons that might be behind the loss of appetite in dogs.

Pickiness

Dogs typically aren’t born picky – rather, 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. Another thing to note if your dog won’t eat dog food? Those who get table scraps tend to be pickier than those who don’t. Same goes for dogs who aren’t fed on a schedule – those who learn they eat at certain times are far more likely to eat than those who aren’t sure when their next meal is coming.

How to tell if pickiness is the issue: A picky dog will often refuse to eat familiar foods—but get extremely excited about new or high-fat foods and table scraps.

Food Quality

What causes a dog not to eat could come down to food quality, including the following scenarios:

Food that’s gone rancid. Some dogs detect – and refuse – food that’s rancid, which usually happens when the fats inside have degraded due to poor storage or age. Higher-fat diets are more prone to rancidity than lower-fat diets. Note too, that 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 specific flavor that was added, 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.
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 that dogs really respond to. And these diets (especially raw) are often high in fat, which dogs also love. Not to mention the fact that fresh foods resemble what people eat (and we all know dogs love to have what their owners are having!).

How to tell if food quality is the issue: If you offer your dog a new batch of her usual food and she eats it right away, that’s usually a giveaway the old batch may have gone bad. If you were feeding kibble and try something with similar ingredients and flavors, but in a wet form, this often indicates it’s an aroma issue. Both scenarios are a little different than having a picky eater.

Boredom

If your dog stopped eating, could he just be bored of his food? Most likely not, according to Dr. Shmalberg. “This appears to be very uncommon without some other factor, like the introduction of new foods or treats,” he says. “Many dogs are content to eat the same diet for as long as it’s offered. If a dog doesn’t know other options exist, he’s pretty unlikely to get bored.” When a dog suddenly decides he just doesn’t want a food anymore, he could have been trained to become picky, or it could be due to something we can’t detect, like a slight change in ingredients that alters the flavour. As they age, dogs do seem to be more likely to stop eating a food for no apparent reason (more on that below). Whether this has to do with changing flavours or true boredom is unclear.

How to tell if boredom is the issue: If your dog appears to get “bored” by his food, switching to a new flavour in his same food or category. For example, going from a beef fresh diet to a chicken fresh diet may do the trick.

Too Many Treats

Treats are pretty much a 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. And then there are the calories. 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.

How to tell if an excess of treats is the issue: Trial and error is pretty much the only way – try reducing the number of treats, sticking to lower-calorie options, or offering treats only on a set schedule.

Household Stress

New animals or people can be stressful to dogs, especially those who are older, routine-driven, or naturally shy. And stress may reduce a dog’s desire to eat because she’s focused on what’s going on around her rather than food.

How to tell if stress is the issue: Assess whether your dog is showing cyclical enthusiasm for her food based on how routine her environment is. 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.

How to Help a Dog Who Won’t Eat Due to Behavioural Reasons

Trying to figure out how to get a dog to eat? First you have to figure out why he’s not eating. If you suspect your pet’s issue is behavioral, try the following strategies. Ultimately, remember that if you don’t establish some food boundaries, your dog will be the boss of you and not the other way around.

Allow your dog to wait it out and fast for two to three days. As time goes on, she’ll probably get much less selective.
Stick to a strict feeding schedule and only leave food out for 10 minutes. Your dog, who is innately driven by routine, will often quickly learn the policy is “eat it or lose it” and get on track.
Cut back on treats. This reduces excess calories and establishes food as more of a rarity, instead of something that the dog’s servant is always ready to provide!
Switch up your feeding location. Also try to minimize any stressors, like noise in the house or unfamiliar guests, around mealtime.
Exercise your dog before meals. Routine exercise can help to improve her metabolism and stimulate appetite. But give her a break before eating – you don’t want to feed her when she’s still excitable and cooling off.
Establish a rotation of different foods. Just keep in mind it’s usually best to switch food types no more than once a week. Otherwise, your dog may try to wait it out for the next day, and then the next, and so on until she gets her favourite.
Consider a more palatable diet. This can include a diet higher in fat or protein, a food with a different form or texture, a food with more moisture or a fresh diet.

Although dogs are food motivated,
they can go without eating for quite some time.

Health Reasons

According to Dr. Shmalberg, the complete refusal of any food (treats, meals, etc.) is far more concerning but less common than the refusal of only certain foods. If a dog won’t eat but drinks water or a dog refuses food altogether, it could be a sign of a health problem. Here are some possibilities.

Dental Problems

Dogs don’t often let their owners know when they’re in pain, and tooth pain is no different. Periodontal disease can predispose dogs to root infections, tooth mobility, loss of teeth, and jaw infections – and owners may have no idea that any of this is going on. Routine dental care is the best prevention, but when problems like these do arise, a dog may reduce his food intake, drop food, or refuse food (especially hard foods like kibble). 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 this 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!”

How to tell if a dental problem is an issue: If your dog stopped eating, it’s not a bad idea to look in your dog’s mouth. Foul odour, loose teeth, large amounts of calculus (coloured, mineral-like material on the surface of the teeth) can all be signs something is awry- but checking yourself is no substitute for a professional exam. See your vet as soon as you can if you suspect a dental issue.

Mental Conditions

Related to stress as described above, there are certain conditions that parallel human psychiatric diagnoses that may impact a dog’s eating habits. Separation anxiety, generalized anxiety, and aggression appear to override appetite in some pups.

How to tell if a mental condition is an issue: Talk to your vet or an animal behaviourist if you see episodes of not eating along with severe behavioural signs.

Physical and Medical Conditions

Most prolonged cases of a complete refusal of food (anything that lasts more than three to five days) – and many cases of chronic undereating – stem from a specific physical or medical condition, like one of the following.

Injury to muscles, ligaments, or other soft tissue. Most common in young and middle-aged dogs, any of these may cause a temporary lack of appetite while the inflammation is at its peak (which usually lasts a few days).
Organ dysfunction. Kidney disease, liver disease, heart failure, and other conditions (more likely in aging dogs) that change the blood concentrations of certain compounds can make an animal feel unwell, and more likely to stop eating. Cancer is also still fairly common in older dogs, unfortunately, and many types of cancer affect appetite.
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 a food with a particular feeling or medical illness. This is especially challenging when a dog is sick for a prolonged period and has been fed multiple foods, all of which he’s probably going to associate with feeling ill. We often make the mistake of leaving food around sick pets, for example, if they’re lying near their food in a crate. Dr. Shmalberg likens this to being sick at a Chinese food buffet: “It’s unlikely you’ll want to go back and eat there anytime soon.”

How to tell if a physical or medical condition is the issue: Consult a professional. Your vet can do a thorough exam to try to localize the issue and may run additional blood work, urine, and fecal exams, and other tests to help check for internal medical disorders.

Recent Vaccinations and New Medications

A visit to the vet, as much as your veterinary team tries to make it comfortable, can still be stressful for your dog. There, she may be given routine preventative medicines (like a deworming agent), and the entire experience can cause a temporary decline in appetite. It’s usually nothing to worry about, as dogs typically get right back on schedule.

Vaccinations, too, cause – intentionally – a brief inflammatory response, which may lead to a day or two of your dog eating a little less or refusing food altogether. This is totally normal. New medications can also affect your dog’s appetite. If they’re added to the food, that may change the flavour and give your dog pause come mealtime.

How to tell if a vaccination or medication is the issue: 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.

Age

Have an old dog not eating on your hands? That’s pretty common – 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 to tell if age is the issue: If you notice—along with a lack of appetite – shifting sleep habits or strange behaviours or vocalizations in your dog, or if he just seems distant or absent. Call your vet, who can prescribe supplements or new foods that can help keep your dog on track in his twilight years.

How to Help a Dog Who Won’t Eat Due to Health Reasons

If you suspect a health or medical cause, consult a vet. Many of these conditions come with vague symptoms in dogs that require close examination in order to land on the right treatment. A careful physical exam will often help to narrow the search for the cause; if necessary, your vet will order more detailed exams (like blood work, X-rays, an ultrasound, or urine or fecal testing) to glean further information.

And keep in mind that most cases of complete food refusal caused by a medical condition will not improve without addressing the underlying cause.

To help dogs with underlying disorders get back to eating, in addition to visiting your vet, here are some basic steps you can take:

Feed your dog in a comfortable environment away from other pets, unfamiliar people, and distractions.
Don’t leave food out all the time. If your dog is sick, this predisposes him to food aversion. Try feeding a few times a day, and only leave the food out for 30 minutes.
Have the dog’s preferred caretaker offer the food, as long as they aren’t too stressed themselves by the whole situation.
If you think your dog might have a food aversion, try switching the flavor of food. Keep other flavors on hand, though, so that you have options if your dog refuses the new flavor or develops an aversion to that.
Add a little water (or heat) to the food to give it more of an odor, which dogs usually like.
Try canned food. The higher fat content and extra moisture make it more palatable to dogs.
Try a fresh diet, ideally one that’s balanced for optimal nutrition. You can make food from scratch in the short term, but know that it may not have all the critical vitamins, minerals, and essential fats your dog needs. Once you go fresh, your dog may develop a strong preference for it – so be prepared to commit.
Up the fat content of your dog’s diet – but only once your vet has ruled out pancreatitis (the condition worsens with more dietary fat). A diet with more than 40 grams of fat per 1,000 calories is recommended.
Increase the protein content of the diet, as long as there’s no underlying kidney or liver failure. This can help maintain muscle mass and make meals more appealing to your dog. A diet with more than 75 grams of protein per 1,000 calories is recommended.
Use tasty “toppers.” These could include a small amount of sugar (avoid xylitol and artificial sweeteners); broth (because of the sodium content, skip broth in dogs with kidney and heart disease); dried meat or liver powders; fish flakes; or gravy (because of the fat content, skip gravy in dogs with pancreatitis). You can also try a sprinkle of favorite treats (just crush or throw in a blender), or a small amount of fresh-cooked food mixed into your dog’s regular meal.
Avoid raw meats and undercooked veggies. The former contains bacteria that may cause additional problems in animals with illnesses (like diarrhea, vomiting, or bacteria moving from the gut into the bloodstream); the latter are often harder to digest.
Consider liquid diets or protein shakes. There are pet-specific liquid diets and over-the-counter shakes for people may work, too, but talk to your vet to make sure they’re safe first. Avoid any products with chocolate and artificial sweeteners.
Avoid syringe-feeding your dog unless recommended by a vet. This can trigger a food aversion and can also lead your dog to associate you with an uncomfortable experience (force-feeding).
Try new bowls, elevated feeding trays, and new feeding locations. Some dogs – especially older ones – may struggle to access a bowl that’s too low. If your dog is weak for any reason, using a plate instead of a bowl can help him get his food easily.
Talk to your vet about any medications your dog is taking. Some drugs can impact appetite sometime after starting, and others may need a dose adjustment.
Ask about medications that may help. Your vet may be able to prescribe drugs that stimulate your dog’s appetite and/or combat nausea related to an underlying condition.
A feeding tube sounds dramatic, but may be necessary to jumpstart feeding in a dog who’s not been eating for some time. The good news? Dogs usually tolerate feeding tubes really well. Your vet can provide options and will reassure you that this isn’t necessarily an end-of-life measure. “Many dogs who’ve had feeding tubes have them removed and go on to live normal lives,” says Dr. Shmalberg.

Long-Term Dangers of Anorexia in Dogs

Just how long can a dog go without eating, anyway? Let’s talk normal dogs first – that is, dogs without any underlying medical issues. “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.”

All that said, if you have a dog who’s picky, finicky, or just playing you for “better” food she likes more, in a battle of the wills, the dog usually wins. Normal dogs will fast for up to five days – sometimes longer – to get what they want. If you think your dog falls into this category, talk to your vet and get her checked out. If there’s nothing wrong, and she’s driving you crazy, it may be time for tough love!

On the flip side, if your dog isn’t eating enough and you suspect an underlying condition – and she’s losing weight – have her checked out. 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 her weight.
If your dog is eating less than 75 percent of her normal amount of food.
If your dog stops eating completely and you know of or suspect an underlying health issue. Some chronic conditions can get suddenly worse in a short period of time and need intervention. (Dehydration is also a concern for a dog who isn’t eating.)
If your dog doesn’t eat for a week, even if she otherwise seems healthy and is acting normal.

Dogs’ bodies are very good at maintaining normal organ function in order to survive a very long period of anorexia. However, anorexia in dogs can cause a number of long-term dangers including:

Loss of muscle mass, leading to weakness.
Reduced production of important blood proteins, which is worsened if the dog has an underlying condition that also causes liver failure or chronic gastrointestinal inflammation.
Changes in electrolytes, which can lead to muscle weakness and other symptoms.
Reduced surface area of the gut, which makes it less likely to absorb nutrients right away when your dog starts eating again – and leaves a dog more susceptible to diarrhea.
Dehydration, if the dog’s water consumption isn’t normal or doesn’t compensate for the lack of water he typically gets from food. (Water content is higher in canned, fresh, and raw diets, and lower in kibble or dry diets.)
Changes in the bacterial population of the gut, which can impact its function.
Inadequate intake of important vitamins and minerals that help with energy metabolism (B vitamins), antioxidant activity (vitamin E), and immune function (zinc).
Inadequate protein to rebuild tissues damaged by underlying diseases.
At worst, while anorexia itself won’t cause death unless it lasts for months, it can certainly shorten a dog’s lifespan and affect his quality of life (especially if it occurs alongside an underlying disease).