What is an elimination diet?
Do you suspect that your dog is reacting to something in their food, but you’re not sure what? Then this article is for you!
Three types of elimination diets
There are three types of elimination diets used in veterinary medicine to diagnose food-related reactions in dogs. Learn why science consistently supports homemade elimination diets as the most reliable way to identify true food allergies.
1. Commercial single- / monoprotein diet
This type of diet contains one declared animal protein source and a limited number of ingredients. It can be used during the diagnostic (trial) phase and, in some cases, for long-term feeding - Available as wet food, dry food, and raw food - Formulated to be complete and balanced
Note
Multiple studies have shown that commercial diets labeled as containing only one protein source often include other animal proteins that are not listed on the ingredient label. Due to the high risk of cross-contamination, commercial single-protein diets are generally not recommended as a first-choice option in an elimination diet (1,2,3,4,5).
2. Commercial hydrolyzed diet
In hydrolyzed diets, proteins are broken down into very small fragments using enzymes. - Hydrolyzed means the proteins are split into small peptides - Reduces the likelihood that the immune system recognizes the proteins as allergens - Common protein sources such as chicken, soy, or liver are often used, but in hydrolyzed form - Available as dry food and wet food (for example Royal Canin Anallergenic, Hill’s z/d) - Formulated to be complete and balanced
Note
Hydrolyzed diets have a documented low, but not zero, risk of cross-contamination (2,5). In addition, some dogs may still react to hydrolyzed proteins, particularly if they originate from a protein source the dog has previously reacted to. One controlled study showed that 16% of dogs with diagnosed food allergy developed clinical reactions to a commercial diet produced for use in an elimination diet (7).
3. Home-made elimination diet
A home-prepared elimination diet is often recommended as the **first choice when food allergy is suspected**, as it provides **full control over ingredients** and eliminates the risk of cross-contamination. A properly formulated home-prepared elimination diet typically consists of: - one protein source - one carbohydrate source - oils and necessary supplements Once the dog has been symptom-free on the elimination diet for approximately 8 weeks, gradual reintroduction of one protein source at a time can begin. This makes it possible to identify which ingredients the dog reacts to and provides a solid foundation for safe and informed choices when selecting commercial diets in the long term.
Choosing an elimination diet
When selecting an elimination diet, it is crucial that the base diet contains a protein source the dog has been exposed to as little as possible in the past. Food-related reactions, including both allergy and other forms of AFR, typically develop through repeated exposure over time, not necessarily after the first encounter with a protein. If a dog has consumed a particular protein regularly, the immune system—or the digestive system—may have become sensitized to it. By choosing a new or rarely used protein source, you reduce the risk of an existing reaction and increase the likelihood that the elimination diet will provide a clear and reliable result. Proteins that the dog has had little or no prior exposure to are often referred to as **“novel proteins.”** Examples may include rabbit, duck, elk, goat, or pollock, but suitability always depends on the **dog’s individual dietary history**. **Example:** If your dog has previously consumed a diet based largely on **white fish**, white fish should not be used in the elimination diet, as the dog may already be exposed and sensitized. If your dog has previously eaten **chicken**, you may instead choose **duck** as the protein source. A…
Typical response to an elimination diet
The response to an elimination diet does not follow one rigid timeline, but there is good evidence on typical patterns. In a synthesis of 209 dogs with confirmed cutaneous adverse food reactions, about half had marked improvement after 3 weeks on an elimination diet, more than 85% had complete or near‑complete remission from week 5, and over 95% were in remission by 8 weeks (Olivry et al., 2015). A small minority (fewer than 5%) needed up to 13 weeks for full resolution, which supports allowing a longer trial before declaring the diet a failure (Olivry et al., 2015). For gastrointestinal signs, there is less precise quantitative evidence, but multiple clinical guidance articles and practice resources consistently note that improvement in vomiting and diarrhea tends to occur earlier than improvement in skin disease, often within the first 2–3 weeks of a strict elimination diet. Most dogs with food‑responsive skin disease improve within 5–8 weeks on an appropriate elimination diet, a small proportion need longer, and gastrointestinal signs usually respond faster, commonly within a few weeks (Olivry et al., 2015).
Duration
It is recommended to follow the elimination diet for **at least 8 weeks**, or until the dog is **completely symptom-free**. Once symptoms have resolved, **one protein source at a time** can be systematically reintroduced to identify **which ingredients trigger a reaction**. This process provides valuable knowledge and makes it possible to choose a **commercial diet the dog can truly tolerate** in the long term.
After 8 weeks
What happens after 8 weeks? Once the dog has been symptom-free on an elimination diet for approximately **8 weeks**, the next phase begins: testing new protein sources. **One new protein source at a time** is introduced alongside the base diet, and the amount is gradually increased over **2 weeks**, while the rest of the diet remains unchanged. If symptoms occur during the testing period, the diet should revert to **base diet only**, and reactions such as itching, licking, or gastrointestinal symptoms should be recorded. Intolerance to the tested protein source is then considered confirmed, and further testing should not begin until the dog is symptom-free again. If the dog shows no symptoms after two weeks, the protein source can be considered safe and recorded as tolerated. In this way, a gradual overview is built of which proteins the dog tolerates and which should be avoided—an important foundation for selecting safe commercial diets going forward.
Treats during an elimination diet
During an elimination diet, **treats are one of the most common reasons the diet fails**. Even very small amounts of a familiar protein can be enough to maintain symptoms or mask the effect of the diet, particularly in cases of AFR. During the elimination phase, **all treats containing animal proteins other than those used in the elimination diet should be avoided**, including chew products, dental treats, and other foods. This also applies to products marketed as “hypoallergenic.” If treats are necessary, they should **exclusively contain the same protein source as the elimination diet**. This preserves the diet as a reliable diagnostic tool and reduces the risk of unintended exposure.
Ready to get started?
A well-executed elimination diet can provide valuable insight into what your dog truly tolerates—and lay the foundation for better long-term health. To make the process as safe and straightforward as possible, we have developed **balanced recipes for home-prepared elimination diets**, based on the principles outlined in this article. You’ll find all recipes collected under the tag **“elimination diets.”** Here, you’ll get simple, carefully designed solutions that offer full control over ingredients—and a solid starting point for making informed decisions going forward.