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Can too much protein in dog food cause diarrhea?

Protein is an essential part of a dog’s diet. However, too much of a good thing is rarely a good thing. When it comes to protein, there is an optimal amount for dogs to consume. 

Can too much protein in dog food cause diarrhea?

High protein diets have become popular for people. Proponents claim that it provides weight loss and better energy. Is a high protein diet good for dogs? Can they have too much? 

Yes, dogs can have too much protein. However, it’s important not to assume protein is the cause of your dog’s diarrhea. There are many other potential causes as well. 

Dog’s Natural Diet 

Dogs were long believed to be omnivores, which means they can live on both meats and plants. However, recent research has called this into question. 

It’s now theorized that dogs are actually naturally carnivores, like cats. This would suggest that they need a high protein diet. However, it’s not that simple. 

Wolves, the ancestors of our modern canines, are certainly carnivores. They will rarely forage for plant food, or eat the contents of their prey’s stomach. 

They are essentially meat eaters. Meat naturally contains a high amount of protein and a moderate amount of fat. 

Dogs have been by our side for thousands of years. Until modern times, dogs ate what we ate, along with what they could hunt for themselves. This led them to eat grains and other plants, which are a staple of our diet. 

Are Dogs Carnivores? 

Are today’s dogs carnivores? It’s clear that they evolved from wolves, which are carnivores. However, their digestive system is highly adaptable.

Over time, dogs have developed adaptations that allow them to enjoy foods that their wild ancestors can’t digest. They have three genes that allow them to digest starches from plants, while wolves don’t have these genes. 

Can Too Much Protein Cause Diarrhea? 

Yes, too much protein in your dog’s diet can cause stomach upset, including diarrhea.  This is known as keto diarrhea. However, too little protein is also problematic for their health, so it’s important to find the correct balance. 

Can The Protein in High Protein Dog Food Cause Diarrhea? 

It’s unlikely that the levels of protein in dog food will cause your dog diarrhea. It’s true that too much protein can cause diarrhea in dogs. However, high protein dog foods are still within the recommended range of protein for dogs. 

High protein doesn’t mean an excessive amount of protein. It simply means it has more protein than typical dog food. 

However, some dogs are more sensitive to protein than others. So, a high protein may be right for one dog, but cause diarrhea for a dog who is sensitive to protein. 

Protein Sources 

While the protein levels in your dog’s standard food is unlikely to cause diarrhea, the protein sources they use can. 

Dogs are not obligate carnivores like cats. However, they do well on a diet high in meat protein. A high protein dog food with inferior ingredients can cause diarrhea. In this case, the problem is that the dog isn’t able to digest the protein sources well. 

Fat Content 

High protein foods typically have a higher fat content as well. Just like protein, some dogs are better able to tolerate fat than others. Too much fat in your dog’s diet can cause diarrhea.

It can also lead to weight gain. Just like us, dogs will store extra fat in their body. 


Allergies are another source of diarrhea that is related to dog food. Ironically, most dog food allergies involve proteins. These include dairy, beef, lamb, chicken, soy, and gluten. 

If your dog is experiencing diarrhea due to their dog food, you may want to speak to your vet about potential food allergies. 

Changing Diet 

If you’ve recently switched your dog’s diet, this may be the cause of their diarrhea. In this case, it’s not the protein content that is the issue. It’s simply your dog’s digestive system not having the opportunity to adjust to the new food. 

No matter what type of diet you choose for your pooch, you’ll need to transition them gradually. 

Begin by feeding them 25% new food and 75% old food. After a day or two, you can increase the ratio to 50% new and 50% old food. After a few more days, transition to 75% new food and 25% old food. 

If your pooch has diarrhea or  vomiting, back up a step and give them more time to adjust.  

What happens when a dog has too much protein?

Protein should make up a good portion of your dog’s diet. However, there are some negative effects of giving a dog too much protein. 

What Happens to Protein in a Dog’s Body

Dogs can’t store protein in their bodies. It must be either used by the body for energy, converted to fat, or excreted by the body. 

Symptoms of Too Much Protein 

If your dog has too much protein, it can cause diarrhea. Other symptoms include lethargy, headache, nausea, and dehydration. 

If you notice yellow patches of grass in your yard, this is likely due to too much protein in your dog’s diet. 

Protein and Kidney Function 

It was once thought that a high protein diet was damaging to the kidneys. This wisdom came from a study that was performed on rats, not dogs. More recent research has discovered that a low protein diet doesn’t aid kidney function in dogs with kidney disease. 

The myth that protein is taxing on kidneys is prevasive. It has been discredited, but the sources reflecting that are few and far between. 

There are health issues that may require protein restrictions, like liver failure. 

Weight Gain 

Some experts believe that a high protein diet is responsible for the rise in obesity in dogs. Today, over half the dogs in the US are overweight or obese. 

On the other hand, a high protein diet is often recommended to help dogs lose weight. Protein can help keep dogs full which leads to weight loss. 

The problem occurs when dogs are overfed a high protein food. The extra protein, fat, and calories can quickly cause weight gain. 

How much protein should a dog have?

After all the research performed by dog food companies, veterinarians, and other experts, it seems we should have a clear answer to this question. 

The daily protein recommendations can vary greatly from source to source. One thing is certain, however. The amount of protein your dog needs depends on their breed, size, activity level, age, and lifestyle. 

Adult Dogs 

The minimum protein requirement for adult dogs is 18-29% protein. Remember, this is the minimum amount of protein your dog needs each day, and there’s quite a range between 18-29. 

Many dog owners are surprised by the range, because we often only hear that 18% protein is the minimum amount your dog needs. This makes it easy to believe that 18% protein is healthy for your dog. 


Puppies are growing rapidly. This growth means they require more protein than adult dogs. A puppy’s food should contain at least 22-32% protein. 

Without a high level of protein, the puppy will struggle to grow and develop properly. Protein is required for muscle growth and energy. 

Pregnant or Lactating Dogs

Pregnant or lactating mothers have the same protein needs as puppies. This is why puppy food is often recommended during these stages. Puppy food is designed to have a higher protein content, and to be easily digestable. 

Active Dogs 

Highly active dogs should be fed a minimum of 20-30% protein. They also have a higher fat requirement than other pooches due to their activity level. This includes working dogs like German shepards, as well as high energy dogs like Jack Russell terriers. 

Senior Dogs 

Surprisingly, senior dogs also need more protein than adult dogs. Without an adequate amount of protein, muscle loss occurs. They may also experience joint damage as a result of too little protein or fat. 

Senior dogs need a minimum of 28-32% protein, particularly if they are overweight.