My dog ate cat food and is now sick

My Dog ate Cat Food and is Now Sick

There are mixed opinions when it comes to the dangers of dogs eating cat food or vice versa. If you are the owner of both a dog and a cat, then you have probably already experienced that at least the dog likes the cat’s food more than its own.

But what if your dog ate cat food and is now sick? Let’s dive a bit deeper into the fundamentals of the different pets food and nutritional needs because there are some major differences.

You might also be interested in reading our article on the top recommended dry dog food products.

My Dog Ate Cat Food and is Now Sick

If your dog is vomiting or have a loose stool after eating cat food, there is a reason for this. Thanks to the carnivorous diet, cat food contains a much higher protein content than dog food, and on the other hand, it doesn’t contain enough fibres which our dogs need.

Dogs with stronger stomachs can handle cat food short-term. In the long-term, however, cat food can be hard on your dogs’ kidney and liver due to containing too much protein.

If after a day it is not looking any better, we recommend you take your dog to the vet. It may not necessarily be because of the cat food, and if the symptoms don’t get better it could be something more serious.

Generally speaking, there’s no immediate danger if your dog accidentally eats cat food. There are, however, some things you should know about the ingredients and your pets different nutritional needs. And if your dog reacts badly to cat food, make sure to store it out of reach for your dog so that it doesn’t happen again.

My Dog Will Only Eat Cat Food

Sometimes, your dog might prefer cat food instead of his own. While it’s common for a dog to like cat food, in some rare cases that’s the only thing they eat. Only eating cat food can cause long-term problems for your dog, as the nutritional needs and fibres are so very different.

We highly recommend you try to get your dog to eat proper dog food, try some different brands and make sure the cat food is out of reach. If you place the cat bowl on the counter, your cat will have no problem jumping up when it’s feeding time. A well-behaved dog will not attempt to jump up and reach the cat bowl and instead will have to eat what’s being served.

Different Nutritional Needs

Cats are pure carnivores while the dog is an omnivore. Therefore, their nutritional needs differ. Cats need more animal protein and fewer carbohydrates than dogs need.

As you can see below, it is the cat that does not get enough of the nutrients it needs, if it only eats dog food.


Protein is large complex molecules that are made up of amino acids. Amino acids include, among others, carbon and nitrogen, oxygen, hydrogen and in some cases also sulfur.

Protein consists of about 16% nitrogen and this is released by various enzymes. If the dog gets less protein, it can regulate the number of enzymes and thus save nitrogen.

The cat needs twice as much protein than the dog. A cat cannot regulate the enzymes if it gets too little protein, which a dog can do. The cat will, therefore, suffer from nitrogen loss.


Taurine is for a cat a vital amino acid that is only found in meat or fish. Taurine is necessary for the female’s ability to become pregnant, but also has great significance for vision and heart.

Even a dog needs taurine, but it can get the same benefits with the help of different amino acids. A cat must get it through its food.

Conventional dog food usually contains too little taurine for the cat to feel good.


Another amino acid is Arginine. Arginine is needed to secrete ammonia into the urine. A cat is rapidly affected by kidney failure if it suffers from a lack of arginine.

Puppies and young dogs that are growing also need to get arginine through their food, but they do not suffer from as severe symptoms as cats do.


Not only is there a difference between the two when it comes to nutrition, but they also have different requirements of carbs.


Glucose taken up by the body must be broken down into the liver before it is converted into energy.

There are two different enzymes that are active in this process, glucokinase and hexokinase. In the cat’s liver, there is only hexokinase, the enzyme that is only active at low levels of glucose.

Dogs and cats receive energy, except for carbohydrates, even in the so-called gluconeogenesis. It is a process forming glucose even from other simpler compounds that the cell cannot break down. It is mainly the brain and the red blood cells that rely on continuous glucose.

The gluconeogenesis starts in the dog when it is eating. The cat, on the other hand, has constant gluconeogenesis.

Fatty Acids

In the animal food, alpha-linolenic acid is added so that the dog and the cat will receive enough omega-6.

The problem in cats and even in puppies is that they cannot convert enough arachidonic acid from the linolenic acid. Therefore, this must also be added in cat and puppy feed.


A cat’s need for vitamin B niacin is about four times higher than the dog’s needs. The cat cannot itself form niacin but is dependent on it being present in the food.

Vitamin A must also be present in the cat’s food because the cat cannot itself convert it.

The cat also has a greater need for thiamine or vitamin B1. The problem with thiamine is that it is heat sensitive and is destroyed by food production. It must, therefore, be added afterwards.

If the cat gets raw fish, the cat may suffer from thiamine deficiency. Raw fish contains an enzyme that breaks down thiamine.

B6 (pyridoxine) helps in the conversion of amino acids. Since the cat has a greater need for protein, it also requires a higher content of pyridoxine than the dog does.


It is not dangerous for either the cat or the dog to eat from each other’s food. A dog works better with cat food than a cat does on dog food. But since they have different nutritional needs, you should not regularly feed them with each other’s food.

If your dog gets sick after eating cat food, then we recommend you take him to the vet if it doesn’t get any better soon. It may be a number of reasons other than just cat food.

And vice versa, if your cat eats a lot of dog food, chances are he will lack a lot of the nutrition needed and become sick and weak.

Check out our article on the best dry dog food, since we started with the ORIJEN dry dog food our dog Baxter has never gone back to eating from the cats’ bowl.

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