Food Intolerance in Dogs: Signs, Treatment, and How It Differs From Allergies

Food intolerance in dogs is a non-immune reaction to an ingredient in a food that a dog has trouble digesting. It most often causes signs of digestive upset like vomiting, diarrhea, gas, or loose stools. It’s also often dose-dependent, so symptoms may get worse if your dog eats larger amounts of the triggering ingredient. 

The cause of canine food intolerance symptoms is often called a trigger. A trigger is the ingredient that your dog’s digestive system doesn’t tolerate. When your dog consumes a trigger ingredient, they may experience stomach upset, vomiting, diarrhea, or other symptoms. 

Any dog can develop an intolerance to a particular food at any point in their life. Some may show symptoms of intolerance as a puppy, while others may be fine eating a food for years before they develop an intolerance. However, the exact reason why some dogs develop them and others don’t is unknown.  

If your puppy starts showing signs of food intolerance early in life, talk to your vet about finding a puppy food that will meet their needs. Puppies have different nutritional requirements than adult dogs to support their rapid growth. Natural Balance Limited Ingredient offers three puppy recipes that may be beneficial for young dogs experiencing food intolerance symptoms. Your vet can help you determine the best product for your pet.  

Ingredients that trigger food intolerance vary by dog, but there are common culprits.  

Some common examples include: 

• Rich/high-fat foods: Think greasy table scraps, fatty treats, or very rich canned foods. 
• Dairy: Many dogs don’t tolerate lactose, leading to gas or diarrhea. 
• Certain proteins: Commonly chicken, beef, eggs, or soy, but can vary widely.  
• Highly processed treats: Especially if they contain many ingredients.  
• Additives or specific formulas: Some dogs react to a particular recipe’s fat level, fiber blend, or preservatives rather than one “named” ingredient. 
• High-fiber ingredients: In sensitive dogs, they can sometimes worsen gas or loose stool. 

Your vet is the best source for helping to figure out which ingredients trigger your dog and which dog food would best meet their needs. One vet-recommended option is Natural Balance. This brand specializes in pet food that is formulated without corn, wheat orsoy, and their Limited Ingredient line offers eight varieties of single-protein diets, including a vegetarian option.  

Food intolerance and food allergy can look similar, but they’re caused by different processes and often come with different symptoms.  

Here’s the simplest way to tell them apart: Intolerance is non-immune and usually GI-focused, while an allergy involves the immune system and often affects skin and ears. 

While that general guideline is helpful, it isn’t foolproof. Some dogs with food allergies have digestive signs, and some dogs with food intolerances may also have skin issues. A vet-guided elimination diet, which is where you feed your dog a specialized diet and reintroduce ingredients one at a time until you find the one causing the problem, is the most reliable way to tell the difference. 

Symptoms of food intolerance and food allergies in dogs can sometimes overlap, but certain signs are more commonly associated with each. 

Common symptoms of food intolerance in dogs include: 

• Diarrhea  
• Vomiting  
• Excessive gas, or flatulence  
• Weight loss  
• Decreased energy, or lethargy  

Common symptoms of food allergies in dogs include: 

• Itchy and/or red skin  
• Frequent ear infections or skin infections  
• Hair loss  
• Licking or chewing the feet 
• Digestive symptoms (vomiting, diarrhea) 

Anaphylaxis is a rare, life-threatening reaction linked to true allergies—not food intolerance—and can cause hives, facial swelling, and breathing trouble. Contact your veterinarian immediately if you see these signs. 

If you suspect your dog has a food intolerance, start a conversation with your vet. 

“Most veterinarians treat food intolerance in dogs through dietary management, typically through elimination diet trials to identify and avoid offending food ingredients,” says Bethany Hsia, DVM, mobile veterinarian and co-founder of CodaPet, in Fresno, California.  

With an elimination diet, you’ll feed a novel or hydrolyzed protein diet to allow the body to “detox” and symptoms to clear, she explains.   

Once your pup’s symptoms resolve and you have been feeding the special diet for eight weeks, ingredients are slowly reintroduced to check which food might be the specific trigger for the intolerance. This is the same method often used to diagnose food allergies. 

With food sensitivities, the goal is to avoid the ingredients that trigger your dog’s symptoms and stick with a formula your dog tolerates consistently. Fortunately, there are many types of complete and balanced dog foods available that take food sensitivities into account. 

Limited-ingredient diets are made with a smaller number of main ingredients than traditional dog foods, which can make it easier to avoid ingredients that your dog can’t tolerate. 

Natural Balance Limited Ingredient Dry Dog Food is an option that comes in eight varieties, each containing only a single, high-quality animal protein and no artificial colors, flavors, or preservatives. 

A novel protein is any protein source your dog hasn’t eaten before. The idea is to choose a protein your dog’s body is less likely to react to because they haven’t been exposed to it.  

Many dog foods that are used to manage food intolerance, including Natural Balance Limited Ingredient, use novel proteins like duck, venison, or bison. 

Novel-protein diets may be recommended as part of an elimination diet, but they only work if your dog truly hasn’t eaten that protein before, including in treats, table scraps, flavored medications, or supplements. 

Hydrolyzed protein foods contain proteins that have been broken down into smaller pieces. This process makes the protein less recognizable to your dog’s immune system.  

Many hydrolyzed protein foods are considered therapeutic veterinary diets, meaning you’ll need authorization from your vet to buy it. Hydrolyzed diets are often recommended for dogs with suspected food allergies or severe food intolerance. 

Your vet is the best resource when it comes to choosing a diet for a dog with food intolerance. They can create a plan to help you identify the problem ingredients and select an appropriate dog food. 

In addition to their Limited Ingredient line, Natural Balance also offers science-backed Specialized Nutrition products as an alternative to support dogs with sensitive stomachs or digestive trouble. Talk to your vet to find the best solution for your dog. 

Managing a dog’s food intolerance starts with identifying the ingredient that triggers their symptoms, then choosing a complete and balanced diet they can tolerate long term.  

Follow these steps to get started: 

1. Talk to your veterinarian 
   Your vet can help determine whether your dog’s symptoms are likely related to food intolerance, food allergy, or another health condition.  
2. Start a vet-guided elimination diet 
   Your veterinarian may recommend feeding a specific diet—such as a novel protein or hydrolyzed protein food—for eight weeks. During this time, your dog should eat only the recommended food.  
3. Avoid extra treats, table scraps, and flavored products 
   Your dog should have only the hypoallergenic diet and water. Treats, chews, flavored medications, and even some supplements can contain ingredients that interfere with the diet trial.  
4. Track your dog’s symptoms 
   Keep notes on your dog’s stool quality, vomiting, gas, energy level, itchiness, and any other changes. This can help your vet evaluate whether the new diet is helping.  
5. Reintroduce ingredients only with your vet’s guidance 
   Once your dog stops showing symptoms on the restricted diet, your vet may have you reintroduce old foods one at a time to confirm which ingredient is causing symptoms. This step is important because improvement on a new diet alone doesn’t always prove which food was the trigger.  
6. Stick with a diet your dog tolerates 
   Once you and your vet identify a food that works well, keep your dog’s diet consistent and avoid switching foods or adding new treats without checking ingredient labels carefully. 

Can food intolerance in dogs go away? 

Food intolerance in dogs doesn’t go away on its own, but the symptoms can be treated and prevented by feeding a diet or treat that does not contain the triggering ingredient.    

How long do food intolerance symptoms last in dogs? 

Food intolerance symptoms can last from a few hours to a few days after the dog eats the triggering ingredient. If the triggering ingredient remains in the diet, the symptoms can last for a long time. 

What is the most common food intolerance in dogs? 

The most common food intolerance triggers in dogs are high-lactose human foods, rich fatty foods like bacon, or certain proteins like beef or chicken. 

Can a dog suddenly become intolerant of their food? 

Yes. A dog may have an intolerance to a certain trigger in the food the first time they eat it. It is uncommon, but a dog can also develop an intolerance to an ingredient in their food at any age, even if they have been eating the same food for a long period of time with no problems.  

Can food intolerance in dogs cause itchy skin? 

Not usually. Generally, food intolerance in dogs causes digestive symptoms like vomiting, diarrhea, gas, and decreased energy.  Itchy skin is more often associated with food allergies to proteins like beef, dairy, and chicken. 

What’s the difference between a sensitive stomach and a food intolerance? 

A sensitive stomach in a dog generally refers to gastrointestinal upset (vomiting, diarrhea, or gas) from difficultly digesting their food. 

A food intolerance in a dog refers to digestive symptoms triggered by an intolerance to high-lactose foods, rich foods, fatty foods, chocolate, or certain proteins or ingredients.