How To Do An Elimination Diet Trial

If you suspect your cat or dog to have allergies, the best way to find out if it’s a food allergy or an environmental allergy is to start with an elimination diet trial.

The elimination diet trial is an 8-week test period, and ideally up to 12 weeks, when your cat or dog can eat one thing, and one thing only. For this trial, we recommend Royal Canin Allergenic food (only available in dry), which is has been extensively hydrolyzed and reduced to pure amino acids. The Allergenic food is also favorable for cats on a urinary diet.

What happens during those 8 weeks? If your cat or dog has a food allergy, you will see a gradual 50% to 100% improvement in their condition, depending on whether other allergies are present.

You may first need to first deworm to rule out parasite and/or do a urine test to rule out any underlying infection.

For more detailed information:

Diagnosing Food Allergies in Cats: Elimination Diet Trials from the Canadian Association of Veterinary Dermatology

How to

Week 1: Start transitioning the food slowly to the allergenic food:

1. Measure what you are currently feeding in a standard measuring cup of the closest size (i.e. 1/3 cup measuring cup). You will keep feeding this amount as the total as you go forward with transitioning over the next 5 to 10 days.
2. For the first 2 days, put a layer of the new food in the bottom of the measuring cup, roughly 10%, then add the rest of the previous diet.
3. For the next 2 days, fill the measuring cup 20% to 40% with the new food and fill with the previous diet.
4. The following 2 days, fill the measuring cup 40% to 60% of the new food and fill with the previous diet.
5. The following 2 days, fill the measuring cup 60% to 80% of the new food and fill with the previous diet.
6. The following 2 days, fill the measuring cup 80% to 100% of the new food and fill with the previous diet.
7. Then feed only the allergenic food.

*Do not offer treats, snacks, human food, flavored medication or food to hide medications or nutritional supplements during the dietary elimination trial.

Journal your pet’s symptoms and everything that touches their lips. This will help you find where challenges may arise and allow your team to help find solutions during the trial period.

Week 2 to 5: Continue fully on the allergenic food.

Week 5-7: Continue on the diet, but now discontinue additional antimicrobial/anti-itch medication (if possible)

Week 8-12: Book a follow-up appointment with us and consider re-doing a urine analysis. If symptoms are resolving by more than 50% then it is most likely a food allergy and the pet can be transitioned to an hydrolyzed, a vegetarian or a novel protein diet (consider provocation trials if appropriate). If resolution is negative or less than 50% improvement, then it is most likely an environmental allergy or a mix of environmental and food allergy. The doctor will be able to recommend other possible treatments and appropriate food to keep the symptoms to a minimum. Royal Canin also makes an atopic dermatitis food (for dog only) that could be effective in helping manage their symptoms.

Keeping a record

It is also important to keep a good record of food intake and symptoms assessment during these 8 weeks. You will want to use the Itch Scale and Fecal Scale for that.

Use this calendar in combination with a notebook to journal and record all pertinent information.

Common pitfalls of elimination diet trial failure:

• cheese or other foods used to hide pills (even if labelled hypoallergenic)
• rawhides, antlers, and other chews
• flavoured toothpaste
• chewable or flavored medicine
• fatty acids such as fish oil
• joint supplements such as glucosamine
• gelatin capsules
• unwashed dishes, bowls and cutlery
• “just a tiny piece” of food or treat
• food dropped on the floor