The Truth about Prescription Dog Food

The Truth about Prescription Dog Food

This is a review article Prescription Diets. In this review, it will touch on the following topics surrounding the Food Sensitivity diets.

  • Legal action against prescription pet food
  • The companies behind prescription diets
  • What’s in prescription dog food?
  • Why Veterinarians sell this food?
  • Research proving it’s deceptive nature
  • Your next steps.

Legal action against prescription pet food

Because the foods are so low quality, their association with Vets is being considered as deceptive and their marketing as being “different to normal dog foods” as fraudulent. 

MOORE V. MARS PETCARE US – California Court of Appeals 2020

“The panel concluded that under the reasonable consumer test, plaintiffs sufficiently alleged that the sale of the prescription pet food exclusively through vets or with veterinarian approval was a deceptive practice.

Also, plaintiffs satisfied the heightened pleading standard for fraud because they alleged sufficient facts to show that prescription pet food and other pet food were not materially different.” 

Not to mention the foods recalls due to dog deaths.

In 2019, Hills had one of the biggest food recalls ever. Around 22 million cans of their food had to be recalled because Vitamin D levels in tested lots were 33 times the recommended safe limit.

Attorney Nyran Rose Rasch – “We believe that hundreds, if not thousands, of pets have died or become seriously ill as a result of eating Hill’s foods with toxic levels of Vitamin D,” says

The FDA investigation found that the vitamin premix had not been analysed and that the final product had not been tested to determine that it met Hill’s specific formulation. Plus, Hill’s failed to obtain certificates of analysis from the supplier of the vitamin.

Who makes the prescription diet?

Hill’s (Colgate) began selling its “Prescription Diet” pet food in the 1960s through vets. In 2004, when Hill’s became a significant player in the prescription pet food market, Royal Canin (Mars) introduced its own line of prescription pet food. At an unspecified time prior to 2012, Purina (Nestle) entered the prescription pet food market.

Hills – Colgate

Royal Canin – Mars

Purina – Nestlé

Not known for their health food products or trustworthy marketing tactics.

What’s in the food?

Here’s an example of what you might find in a diet for digestive health. For a start, prescribing a dog with digestive issues a processed food, is the equivalent of sending a human with stomach problems to McDonalds. It makes no sense.

  • Animal by-products – animal fats, digest (see how bad these are below)
  • Brewers Rice –  Low quality carb filler, unnatural for dogs.
  • Dried whole egg – powdered egg, extremely low quality protein source
  • Maize gluten meal – Connected to allergies and intolerances by holistic vets


  • Animal by-products –  digest (see how bad these are below)
  • Caramel – “coloured with caramel”
  • Dried beet Pulp – Horse feed
  • Maize  – which dogs should not ever consume.
  • Rice and rice flour – too high in rice, high grain diets are unnatural for dogs

Here’s a look at what can go into animal-by products:

Why is it recommended by Vets?

In the UK there are seven universities offering degrees in veterinary science. Nutrition however, plays a minor role in their education.

The average Vet only receiving 19 hours of nutrition training for all animals.

To put that into context, I’d say I’ve spent 1hr per day learning about canine nutrition (low end), 5hrs per week (not weekends) for the last 3.5 years.

I’ve spent around 910hrs learning about dog nutrition, just dogs.

A lack of education and chronic underfunding (or in some cases just greed), many universities are very open to external sources of revenue and are happy to accept ‘sponsorship’ from companies despite glaring conflicts of interest. Over the decades, The Big Three (Colgate, Mars and Nestle) have exploited this situation to develop ever closer ties with vet schools around the world, providing funding and education. 

The Nutrition Textbooks

The most popular text on the subject, entitled “Small Animal Clinical Nutrition” is made by Hill’s. They also make the accompanying “Quick Consult” guide and the “Key to Clinical Nutrition”. Royal Canin’s best-known texts are the Encyclopedia of Canine Clinical Nutrition and the Encyclopedia of Feline Clinical Nutrition.

It probably won’t surprise you to hear that these texts are not what most people would call ‘impartial’ on the subject of pet food.

As an example, the Canine Encyclopaedia dedicates more space to promoting Soy Protein Isolate Hydrolysate (a common Royal Canin ingredient) than it does to exploring the entire subject of home-preparing a fresh food diet.

The very last sentence in the entire textbook perfectly summarises how Royal Canin consider your sick pets: “Ideally, space should be organized in such a way that owners are led to buy a new supply of food for their dog, and even to buy new products for the dog that they have not seen before (e.g., chewing bars for dental hygiene)”.

This book is one of the primary sources of information on pet nutrition for vets. Unfortunately, your Vet knows little to nothing about nutrition.

Evidence of how deceptive these diets are, is now coming out in canine nutrition research:

  • 13/14 Vet foods use for food elimination diets contain ingredients that weren’t on the label. (1)
  • 7/8 Vet diets use for weight loss were deficient in nutrients according to guidelines. (2)

Your next steps

The power of food is that it can make a dog healthier. Just like with us humans, when we start eating a super healthy diet, it undoes the damage of an unhealthy diet.

Let’s sort out a diet that works for your dog.

I have health plans for common issues here

Get in touch through contact us page to speak to Cam Wimble (certified dog nutritionist)


  • Ricci, R., Conficoni, D., Morelli, G. et al.Undeclared animal species in dry and wet novel and hydrolyzed protein diets for dogs and cats detected by microarray analysis. BMC Vet Res 14, 209 (2018).
  • Olivindo, Rodrigo FG, et al. “Evaluation of the nutrients supplied by veterinary diets commercialized in Brazil for obese dogs undergoing a weight loss program.” Journal of Animal Physiology and Animal Nutrition.
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