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What Is An Elimination Dog Food Diet? The Expert Guide

Written By Vedrana Nikolic | Canine Coach, B.A Ethnology & Anthropology, M.A Semiotics.
Edited & Fact Checked By Renae Soppe | B.A Journalism & Science. 
Last Updated: 7th January 2024

As a pet parent, seeing your dog in discomfort from allergies is always concerning. You’d love to help, but not being able to put your finger on what caused the allergic reaction is quite a challenge.

In these cases, your vet might suggest conducting a so-called elimination diet. But before you change your dog’s food, here’s everything you need to know about this dietary trial first.

Identifying Allergies In Dogs

Allergies in dogs are a result of over-reactivity or hypersensitivity of their immune system to a specific substance. In other words, their bodies see the substance as a foreign invader and make antibodies to fight off the enemy.

Dogs can experience environmental and dietary allergies, which are often manifested through visible symptoms such as redness, rash, hot spots, itchy skin and sometimes fur loss. Allergies are actually quite common in dogs, and most of them are caused by environmental factors. Only around 10% of allergies in pets are caused by food or a specific ingredient (1).

Now, dogs usually aren’t born with food allergies. Instead, they develop them over time, as their hypersensitive immune responses build up within their bodies. In most cases, food allergies first show up during the first three years of a dog’s life, but they can also happen later in their life stage, especially with dogs that have been eating the exact same diet for many years (2).

Related: How To Transition To New Dog Food & Avoid Upset Stomach Symptoms?

Most Common Food Allergens

Technically, your pooch could develop an allergic response to any ingredient found in food. However, the main culprits of food allergies in dogs are proteins and complex carbohydrates. And among them, these are the most “problematic” ingredients (3):

  • Beef
  • Chicken
  • Eggs
  • Lamb
  • Soy
  • Wheat
  • Dairy

Why are these ingredients such common allergens?  Well, they’re often found in pet food formulas, so dogs are generally more exposed to them. In other words, it’s pure statistics. For the last few decades, beef and chicken were the most popular ingredients, with pretty much every brand offering at least one formula featuring these proteins. In fact, these two ingredients often also end up in formulas primarily consisting of other protein sources.

Related: How To Calculate Carbohydrates In Dog Food.

It’s worth noting that there’s no such thing as 100% hypoallergenic dog food. Instead, formulas labelled as hypoallergenic contain no high risk ingredients and usually just one, novel protein. The term novel indicates a type of protein that is rare and “new” to your dog in terms of diet. As such, it shouldn’t cause an allergic reaction.

Related: The Best Hypoallergenic Dog Food.

Elimination Diet As A Diagnostic Tool For Food Allergies

The two diagnostic techniques used for determining food allergies in dogs are intradermal and blood testing, but neither method has great accuracy. That's why many veterinarians straight up avoid doing these unnecessarily detailed and expensive tests and use a more classic approach, the elimination diet (3).(4)

An elimination diet is a limited ingredient meal plan for feeding your pooch, which should help you narrow down which ingredients in the food your dog is allergic to. The method is very meticulous and consists of three phases:


The elimination phase is exactly what it sounds like. You start by switching your canine companion to eating a single formula for up to 12 weeks. The formula you go with should ideally include a single protein and a single carb source, neither of which were previously included in your dog’s diet. During this phase, your pooch should only eat that specific recipe for every single meal. No treats, supplements, dental chews or begged-for food scraps are allowed during this time, as they could feature ingredients your dog is allergic to.


After 12 weeks of eating the same old thing, it’s time to spice up your fur baby’s diet a bit. The challenge phase involves reintroducing one ingredient at a time and observing for any returning allergy symptoms. Of course, you should let each ingredient do its magic by giving it a 2-4 week trial to see whether your dog’s immune system will respond to it.


If your pooch reacts to the reintroduced ingredient, cut it from the diet right away and go back to feeding your dog the strict elimination diet. This starts the third phase of the method, which is confirming whether you’ve found the “troublesome” ingredient. If, after 2-4 weeks from restarting the elimination diet, negative symptoms are resolved, that’s proof that your dog is allergic to it.

However, that might not be the only ingredient your pup reacts to. This is why you shouldn’t quit the elimination diet after the third phase. Instead, check the other ingredients commonly found in your dog’s favourite recipes.

The elimination diet method is very strict and time consuming, but it’s currently the most accurate way of diagnosing dogs with food allergies.

Elimination Diet Options

Even just by walking down the aisle at the pet shop, you can probably find a bunch of diet options for dogs dealing with allergies and sensitivities. However, when you’re performing an elimination diet trial, you should resort to one of the three options available.

Veterinary Prescription Limited Ingredient Diet

Don’t get confused by the name of this type of formula. The prescription dog diet doesn’t contain any medication nor does it necessarily require you to have a vet’s prescription to buy it. Instead, the term only indicates that this is not a typical diet, but one that’s designed to address a specific health condition.

Related: What Is A Limited Ingredient Dog Food Diet?

The limited ingredient diet (LID) is formulated for dogs with food allergies, so they usually contain fewer ingredients and a single, uncommon protein source. And theoretically speaking, the formula is perfect for an elimination diet.

However, due to so many widely available diets now including novel proteins, such as rabbit, kangaroo and venison, these ingredients aren’t that “new” to many dogs anymore. That’s why these prescription LID diets aren’t suitable for every single dog.

Veterinary Prescription Hydrolyzed Protein Dog Food

As you know, an allergic reaction occurs when a dog’s immune system misidentifies certain ingredients as a potential threat. In most cases, this happens with proteins.

Related: What Is A Hydrolyzed Protein Dog Food?

This type of prescription dog food features proteins chemically altered through a water-based process called hydrolysis  (5). In the process, protein molecules are broken into smaller components, which are amino acids and peptides. This prevents the immune system from detecting the protein as the allergen. In other words, your dog’s body won’t recognise which exact animal the protein comes from due to the changed chemical structure.

It’s worth noting that, unlike most LID dog food, hydrolyzed protein recipes are typically sold only with a vet’s prescription. That’s because they’re mainly aimed at dogs going through the elimination diet and are not intended for prolonged use.

Home Cooked Diet With Novel Protein

Finally, many pet parents opt for making elimination diet meals at home.

However, making balanced home cooked meals for dogs is already difficult as it is, and it gets even more difficult when the ingredient list is limited. In most cases, these diets are incomplete and unbalanced unless formulated by a veterinarian. In fact, studies show that over 90% of home cooked dog diets don’t meet the essential nutritional requirements(6).

If you do choose this option, it’s best to consult your vet about the diet plan. They can help you create balanced meals for your pooch, even during the elimination diet.

Related: The Best Sensitive Stomach Dog Food?

Final Thoughts

Even though it requires time and commitment, an elimination diet is still the best method of determining food allergies in dogs. True, your dog might not be pleased with the rigorous and bland diet.

But think of it this way - you’re not limiting food options, simply searching for a culprit of their discomfort in order to eliminate it from future meals.


  1. “Seasonal Allergies vs Food Allergies in Dogs: What’s the Difference?” January 27, 2020. Vetericyn. Retrieved June 17, 2023.
  2. “Food allergies in dogs”. The Kennel Club. Retrieved June 17, 2023.
  3. Mueller RS, Olivry T, Prélaud P. (2016) “Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats”. BMC Vet Res. 2016 Jan 12;12:9. doi: 10.1186/s12917-016-0633-8. PMID: 26753610; PMCID: PMC4710035.
  4. Wilson, S; Datz, C. September 30, 2020. “Performing a Diet Trial to Identify Food Allergies in Dogs and Cats”. Today’s Veterinary Practice. Retrieved June 17, 2023.
  5. Coates, J. January 6, 2023. “What to Know About Hydrolyzed Protein Dog Food.” PetMD. Retrieved June 17, 2023.
  6. Stockman J, Fascetti AJ, Kass PH, Larsen JA. (2013). “Evaluation of recipes of home-prepared maintenance diets for dogs”. J Am Vet Med Assoc. 2013 Jun 1;242(11):1500-5. doi: 10.2460/javma.242.11.1500. Erratum in: J Am Vet Med Assoc. 2014 Jul 15;245(2):177. PMID: 23683013.

Vedrana Nikolic

Vedrana Nikolić is Gentle Dog Trainers Canine Coach, Professional Writer, Anthropologist & dog lover.

With a Masters Degree in Semiotics & Bachelors Degree in Anthropology, studying the communication between animals and humans, Vedrana is able to use her expertise to analyse and review dog products and write informative posts on canine behaviour and training.

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