Small Animal Referral Hospital Diet Trials

• Diet trials are the optimal way of assessing for dietary intolerance
• Up to 3 diets may need to be trialled to assess response
• A favourable response is typically seen in the first 2-6 weeks
• Failure of response or exacerbations of signs are common if there is access to other food items

Diet trials are used to evaluate for the role of dietary intolerances as a cause of gastrointestinal or dermatological signs. Unfortunately, there is no available diagnostic test that predicts what a patient’s intestines are intolerant of.

Exclusion diet trials involve feeding one of the following diets - your clinician will make a specific recommendation based on your pet’s diet history and clinical findings.

• Hydrolysed diet - where dietary proteins are fragmented such that the original protein cannot be recognised in the intestines so cannot trigger an adverse reaction
• Novel diet - commercial or home prepared diets based on food items the patient has not previously been exposed to. Recipes for home-cooked options should be formulated by a board certified veterinary nutritionist - please liaise with your clinician if you are interested in this
• Low fat diet
• High fibre diet

During a diet trial the prescribed diet should be fed exclusively, with no other food items available - this includes avoiding any flavoured chews, treats or pastes during this time. Fresh water should be available at all times.

The new diet can be introduced gradually by mixing it with the current diet or feeding it alongside the current diet for 3-7 days before feeding it exclusively, or, if your pet currently has severe clinical signs an immediate transition may be recommended.

It is not uncommon for anti-nausea medication and/or appetite stimulants to be prescribed alongside a new diet to support its introduction. If you have any palatability concerns during the diet trial – please contact us.

It is not uncommon for multiple (up to 3) diets to need to be trialled before seeing a response. Many patients will start to show a favourable response (>75% improvement in signs) to a successful diet trial in the first two weeks, although a full response may take 4-6 weeks. If there has been a partial (25-75% improvement in signs) over the first 2 weeks, extending the diet trial is recommended. If there has been no (<25%) improvement in the first 2 weeks, the diet is unlikely to be successful and an alternative diet or treatment pathway will be recommended.

If a dietary trial is successful in resolving your pet’s clinical signs, this diet should be fed for a minimum of 3-6 months, whilst the gastrointestinal inflammation resolves. Following this, you may choose either to continue the diet longer term, or ‘challenge’ the diet - this involves feeding the prescription diet as a base, and each week adding a sole source protein or carbohydrate to the diet and evaluating whether this causes a recurrence of signs (and should be avoided) or does not cause any signs (and can be fed moving forwards). By feeding a different food item in addition to the original prescription diet each week, you should be able to identify a series of ingredients that can be used or need to be avoided, and ultimately may be able to use these lists to identify a suitable non-prescription diet based on these, moving forwards. If your pet has a reaction to a food item, they should revert to the prescription diet alone, until their signs have resolved and you continue with a new dietary item to challenge. Up to 70% of patients will need original prescription diet long term to remain in remission.

During the diet trial no treats should be provided. If the diet is being fed longer term, using dietary challenge you may be able to identify foods to base treat items on, that your pet can tolerate without recurrence of their signs. Alternatively, there are a small number of commercially available hydrolysed treats - your clinician can provide you with information on this to suit your pet’s needs.

Please see our associated web page on chronic inflammatory enteropathies for further supporting information.