Why Isn’t My Dog Eating? Top Causes of Lack of Appetite in Dogs

Dogs love food. From energetic puppies to distinguished seniors, they seem to devour just about anything you put in front of them – anytime, anywhere. When dogs refuse to eat, it can be quite upsetting. Although dogs are motivated by food, they can also go without eating for some time.

Lack of appetite in dogs can have countless causes – from health conditions to behavioral issues, to the type of food you offer your pet. Lack of appetite should be treated seriously, especially if you have a greedy puppy.

Why Won’t My Dog Eat?

Most dog owners are used to seeing their furry friends eating everything from their food bowls. When dogs refuse to touch their food, their owners may panic.

Lack of appetite is one of the frequent reasons why dog owners present with their four-legged friends to the vet. If your dog’s loss of appetite lasts more than 24 hours, do not ignore it. Appetite loss often represents a warning sign that something else is happening in your dog’s body.

The reasons why dogs stop eating are usually be divided into three major categories:

  1. Medical
  2. Behavioral
  3. Problems with the food itself

1. Dogs Won’t Eat Due To Medical Reasons

In general, the reasons why dogs stop eating are the same as in humans.

You can think of a health problem if your dog refuses food for several days. A passing virus or fever can be what generates a lack of appetite in dogs. If this behavior overlaps with vomiting and/or diarrhea, it is advisable to contact the veterinarian immediately. They can be symptoms that indicate a more severe medical condition.

The list of possible medical causes for lack of appetite in dogs is very long and can include anything that could cause pain, nausea, lethargy, or stress. The most common reasons are:

  • Dental disease
  • Oral pain
  • Nausea
  • Vomiting
  • Diarrhea
  • Intestinal parasites
  • Pancreatitis
  • Upset stomach
  • Infections
  • Fever
  • Cancer
  • Liver disease
  • Kidney disease
  • Inflammatory bowel disease
  • Congestive heart failure
  • Pulmonary disease

These are just a few examples of medical problems that can lead to loss of appetite in dogs; there are many more possible reasons.

Sometimes dogs stop eating one food type but eat the other without problems. Usually, this happens to dogs that consume dry food on a daily basis. Due to various oral problems, dogs can have difficulties chewing dry food, so it is best to offer them soft food.

Recent vaccination can be another reason why your dog is not eating anymore. Although vaccines save the lives of millions of pets, being available for many contagious diseases, they still have a series of adverse reactions. Most of them are minor and short-lived, and lack of appetite is one of them.

The same thing can happen with medicines. Some medications can cause nausea as a side effect, which leads to decreased appetite.

2. Dogs Won’t Eat Due to Behavioral Reasons

Low appetite can also be caused by anxiety, stress, or fear, as it happens in humans. However, you must remember that what you think is stressful for you may be different than what your dog sees, and even minor things can cause anxiety and stress.

Anxiety can be caused by changes in your dog’s routine or environment, such as:

  • New people
  • Pets in the house
  • Car rides
  • Loud noises: construction, storms, or fireworks
  • Changes in its mealtime
  • Changing the place where your dog eats

Many dogs do not like to eat near other pets. When there are several pets in the household, intimidation or the desire to dominate may occur, and your dog may start to avoid its food bowl. It is recommended to keep pets separated when it is feeding time to avoid this from happening.

Usually, if the problem is related to stress or anxiety, dogs will start eating again after a day or two, after they have adjusted to the changes in their routine. Some dogs may need medical treatment to reduce stress and anxiety if they are manifested frequently.

Boredom can be another reason why your dog stops eating. Although many dogs are happy to eat the same diet as long as you provide it, it still can happen.

When a dog suddenly decides it doesn’t want a particular food anymore, it could mean it is getting picky, or it could be due to something we can’t detect, like a slight change in the ingredients that modifies the flavor.

If your dog seems to get “bored” with its food, switch to a new flavor in the same food category. For example, switching from a fresh beef diet to a fresh chicken diet can be a real trick.

3. Dogs Won’t Eat Due to the Food Itself

If your dog is not eating, it could be because of its food, which may be old, expired, or spoiled. Take a look at the expiration date on the box or bag of your dog’s food. Also, ensure your dog’s food is always stored in an airtight container – dry food can mold if stored improperly. All dog food containers and bags must be sealed, and the food must be thrown away if the expiration date has passed. Opened cans can be sealed with plastic wrap or a matching lid and refrigerated for up to two days.

Top Tips

Do not give your dog canned food that has been left outside for more than two hours

If the food is spoiled, some dogs can detect it and refuse to consume it. Usually, when the fats inside food have degraded due to improper storage or time, it becomes rancid. High-fat diets are more prone to rancidity than lower-fat diets.

High-fiber foods tend to be less palatable to dogs than lower-fiber foods. Some weight loss diets fall into this category.

Exposure to fresh or raw diets can also cause dogs to refuse their regular food. Raw diets are often high in fat, and dogs love them. Not to mention the fact that fresh food is similar to what people eat, and dogs love that too.

Too many treats can make dogs picky. Dogs like novelty, and when they get treats of different types and flavors, they will want the same thing from their food. If dogs don’t get the same flavor, they will start to refuse their regular diet.

Long-Term Risks of Lack of Appetite in Dogs

Dogs can refrain from eating for up to five days to get what they want. If your dog hasn’t eaten for a few days, take it to the vet and have it checked.

On the other hand, if your dog isn’t eating enough (and it is losing weight) and you suspect an underlying condition, take it to the vet. Here are some signs that will tell you it is time to pay a visit to the vet:

  • Weight loss
  • Your dog eats less than 75% of its usual amount of food.
  • Your dog stops eating, and you know or suspect an underlying health problem. Some chronic conditions can suddenly worsen over a short period and require intervention. Dehydration is also a concern for dogs that are not eating.
  • If your pet doesn’t eat for a week, even if it looks healthy and acts normal.

Dogs’ bodies are very good at maintaining normal organ functions to survive a very long period of not eating. However, a lack of appetite in dogs can cause a number of long-term risks, including:

  • Loss of muscle mass, which leads to weakness.
  • Reduced production of important blood proteins, which gets worse if the dog has a condition that causes liver failure or chronic gastrointestinal inflammation.
  • Changes in blood electrolytes, which can lead to muscle weakness and other symptoms.
  • Dogs are more prone to diarrhea.
  • Dehydration – if the dog’s water intake is abnormal or does not compensate for the lack of water it usually gets from food.
  • Changes in the bacterial population of the gut, which can affect its function.
  • Inadequate intake of important vitamins and minerals that aid energy metabolism (B vitamins), antioxidant activity (vitamin E), and immune function (zinc).
  • Inadequate proteins to rebuild tissues damaged by disease.

At worst, while the lack of appetite itself will not cause death unless it lasts for months, it can certainly shorten dogs’ lives and affect their quality of life.

What to Do When Your Dog Stops Eating

If your dog is lethargic, vomiting, or has diarrhea in addition to its loss of appetite, consult your veterinarian immediately. If you don’t notice any of these symptoms, here are some ways to make your dog to eat:

  • Add hot water or unsalted chicken broth to your dog’s food. Hot liquids enhance the flavor. If you add liquids over the dry food, let them soak for 5-10 minutes before serving the food to your dog.
  • Heat your dog’s wet food for a few seconds in the microwave. Canned food can become hot quickly, so test it on the back of your hand before serving it to your dog.
  • Try mixing some plain boiled, boneless, skinless chicken and rice with its dry food to encourage eating.
  • Add a probiotic on top of its food. It will make eating more enjoyable and help heal any inflamed or irritated gut by rebalancing healthy gastrointestinal flora.

If you have tried these tricks and your dog continues to refuse food, visit the vet to rule out any underlying medical conditions.

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Dr. Lulia Mihai, DVM

I am a veterinarian from Romania with a Master's degree in pets' pathology and a PhD in pets' cancer. I have experience in researching (I wrote various academic articles for international journals) and writing academic and blog articles. I started writing about pets over 3 years ago and made it a full-time job. I have a bunch of pets and I think they are lucky to have the vet at home. I like to educate people about everything there is to know about pets - nutrition, training, behaviour, diseases, you name it! I've written hundreds of pet articles in these 3 years.