Why do vets recommend Hill’s Science Diet / Prescription Diet?

I’m a qualified pet nutritionist, yet I rate Hill’s Science Diet, Hill’s Prescription Diet, and Mars Royal Canin poorly.

Vets on the other hand religiously defend and endorse these brands. Why is that? Why do vets recommend Hill’s Science Diet, Prescription Diet, and Royal Canin?

Take a look at the ingredients on any bag of Hill’s Prescription or Science Diet dry food. You’ll find mostly grains – wheat, sorghum, corn, rice.

Shouldn’t these animals have a diet mostly of animal or whole prey?

In fact you’ll find much more grain in these products than meat. Basic animal nutrition 101 tells us how odd it is to feed a dog as a facultative carnivore from the Order Carnivora, and more so a cat as an obligate carnivore, a diet comprising mostly of grains. Where’s the science in that?

It simply doesn’t make sense.

So why on earth do vets recommend these products?


Yes, that’s true, but we need to ponder this as it is unlikely many vets have ever considered why. If you’re a vet, and you’re reading this, have you ever considered why these products work?

Why do vets recommend Hill's Science Diet / Prescription Diet?

Vets see an improvement in pet health when they are transitioned to Hill’s Science or Prescription Diet products. Pretty convincing evidence, wouldn’t you agree? An animal comes in with an illness and poor blood results, and a few weeks after the transition in diet their blood results show an improvement. Miraculous!?

Unfortunately it’s a glaring oversight. Let me explain, as there’s one key factor almost always unconsidered:

Most kibble is absolute rubbish. Junk food. A convenience product designed for profit.

Sadly business is business, and if these manufacturers put your pets before profit they’ll never succeed as a business, and the businessmen behind those businesses will never own a Lamborghini (which is generally the driving motivation behind a business).

These simple facts (blame it on Capitalism if you will) are the fundamental reason why most dog foods are unhealthy. Healthy foods cost money, unhealthy foods make profit.

Unfortunately for our pets most people don’t realise how bad these products are, and they feed them continuously to the pets they love, without ever questioning it – ever! We’re blindsided by some of the best product marketers in the world from some of the leading conglomerates in the world – Mars, Nestle, and Colgate-Palmolive.

Why do vets recommend Hill's Science Diet / Prescription Diet?

Millions of dogs are fed poor quality kibble and consequentially their health will suffer over time. Obesity, diabetes, arthritis, heart disease, kidney disease, IBD, IBS, allergies, and so forth, can all be caused by bad diet. Hill’s have an answer for all these diet-related health conditions in the form of cleverly-marketed “premium” or “prescription” diets. So do Royal Canin.

Hill’s is a product of toothpaste and shampoo conglomerate Colgate-Palmolive, and Royal Canin is a product of Mars.

The penny drops

Let this simple fact resonate, as it will give you the answer to why vets recommend Hill’s Science Diet, Prescription Diet, and/or Royal Canin:

If you feed your dog junk food, then replace it with something marginally better, you’ll very likely see an improvement.

It’s not a miracle, and it doesn’t mean the expensive premium/prescription diet is healthy or optimal. It’s just marginally better than the rubbish fed previously which more than likely caused the illness in the first place.

In many cases a prescription food is tailored to reducing the symptoms of the specific condition. For example, a kidney diet has reduced phosphorous (and more often than not less meat). A weight loss diet will have lower fat (by reducing meat and increasing grains/legumes).

Corporate pet food manufacturers convince us these foods are optimal when they’re not. In some case they even use the word Optimal in the brand name (Optimum, also by Mars).

A dog or cat suffering kidney problems shouldn’t be fed a dry food period. An overweight dog is likely overweight because the previous diet was high in carbs and grains their bodies were unable to process. In cases such as this, reducing their meat intake definitely isn’t the optimal solution. A diet with lacklustre meat will likely lead to other health issues over time, even on expensive “premium” diets packed with grains, even the ones using marketing words like “Science” in the name.

Most of the time the deteriorating health of our pets (especially pets with a health condition) is attributed to the worsening of the condition or “old age”, or just plain bad luck, which is far from the whole truth. Diet is so often overlooked as the cause of an initial health condition, and also the cause of subsequent health conditions while the pet is on the premium/prescription food. It’s strange how the term “We are what we eat” is never translated to our pets.

These are fundamental reasons why toothpaste and shampoo company Colgate-Palmolive (makers of Hill’s) and confectionery company Mars (makers of Royal Canin) make an absolute killing out of expensive premium and prescription diets regardless of whether they’re optimal or not, and completely irrespective of the grains they’re made from.

The mass poisoning of pets by vets 1991 – 2015 (and beyond)

This is a controversial video by Sydney vet Dr. Tom Lonsdale, a campaigner against the junk pet food industry since 1991.

  1. “A dog or cat suffering kidney problems shouldn’t be fed a dry food period.”
    Thank you so much for confirming it! A vet told me that years ago when one of my cats aged 4 had a case of struvite. Almost 10 years later with nothing but regular food, he’s had just once his teeth cleaned, and the vet of the town we’re living in can’t believe he is so healthy. At the clinic, they do insist on Hill’s and Royal Canin and Virbac (a French brand), but I’ve never bought any of those, as the ingredients don’t list meat as being the primary content.
    One issue though: he’s just been diagnosed with hyperthyroid, I suspect that the water quality could be the trigger? So I’ve started filtering his water supply.
    Thank you so much!

  2. Hi, I almost feel guilty adding to the questions that have been asked of you, but I’m at my wits end.

    I have a 4.8 year old blue staffy (Pumba) who, over the past 7 months, has been consistently getting interdigital cysts.

    Before I go on, I just want to say that nothing had changed in regards to his food, or anything else when this all started. Before that he was fine.

    Ok, he started out with just one cyst which I didn’t know what it was to begin with, it was just a horrible, nasty looking blister type thing between his toes. I took him to the vet, who told me what it was and that it could be from an ingrown hair, a prickle or something he stood on in the yard. He just lanced it, squeezed the blood out of it (but didn’t find a prickle, or anything) and gave him an antibiotic injection. I took Pumba home and bathed his paw until the cyst went away.

    I thought that was it, but no…another one came up on the other paw. So we did what the vet did, then bathed it until it was gone and all was good. Long story short, he ended up getting cysts on all his paws, even though I had been bathing them as soon as I saw them. So back to the vet. He was put on a course of antibiotics and apoquel to treat him for allergy. I was told that he may need ongoing apoquel (at least during Spring/Summer), to change him to Hills Dermcomplete, which must be the most expensive kibble ever made (and which I cannot afford), but I have changed his diet (he was having a combination meat/fish and chicken kibble), he is now having kangaroo meat and Savor Life salmon kibble. I am also now putting flaxseed oil on his dinner and I’ve made up a spray that I spray on his feet twice a day (1 cup green tea, 2 tablespoons apple cider vinegar).

    He seemed to be getting better, in that all of the cysts cleared up. But now, he has got a couple back again, so I’m constantly bathing his paws. And you can look at him one minute and nothing, then you look at him literally 5 mins later and he has a cyst! It’s so annoying. I can’t imagine how horrible it is for him.

    Can you please tell me, if this is a food (or possibly nature) allergy thing, what would be the best I can give him. I’m looking at Meals for Mutts kangaroo single meat (kibble), or is there no kibble that is any good?

    Any help you could offer would be greatly appreciated!
    Thank you.

    • Zignature has arrived in Australia, available at Pet Circle. May be of use to you as well as it’s considered a limited ingredient food and has many proteins to choose from.

    • Reply
      Pet Food Reviews (Australia) February 16, 2022 at 6:21 pm

      Hi Marrianne, if the issue is diet-related, which I suspect it might be given what you’ve said, the best starting point is considering the root cause. This would be the kibble you fed originally (feel free to mention the brand, or message me privately). Food intolerances build up over time, and poor quality foods can disrupt the microbiome which takes a long time to heal.

      If Hill’s Derm Complete showed an improvement then this is further evidence the original food was causing the cysts. Unfortunately, like many Hill’s dog foods, it’s not ideal for a dog as essentially a meat-eating animal. Derm Complete is mostly cereals, low protein, and whereas might seem to improve skin conditions may cause other health issues in the long term.

      My recommendation would be to try a food without cereals or wheat, and possibly with a meat protein which is novel to your dog. In terms of kibble, perhaps Canidae PURE, Taste of the Wild PREY, or Australian brand Lifewise (such as their Kangaroo formula). If you’re willing to try a more fresh food then maybe Lyka or Frontier Pets as high end offerings more species-appropriate. You don’t need to feel locked in to any of these brands, but worth a try for a few weeks to see if there’s any improvement in your dog.

      It should be fine to keep up the flaxseed and spray, and hopefully in time his condition improves.

      • I put my work email on the previous comment. I meant to put my personal one (which is what I’ve submitted now).

      • Thank you, this is very helpful information!

        The brand Pumba was on was Natures Goodness, grain free, chicken, duck and garden vegetable and I mixed this with Big Dog Como wet food (Ingredients: Beef, finely ground beef bone and cartilage, lamb, finely ground lamb bone and cartilage, chicken, finely ground chicken bone and cartilage, pork heart, beef and lamb heart, beef and lamb liver, beef and lamb kidney, whole fish (salmon & sardines), seasonal fruits, vege and herbs (kale, spinach, broccoli, bok choy, silver beet, carrots, celery, beetroot, lettuce, cucumber, capsicum, apple, orange, pear, tomato, strawberry, ginger & parsley), cold pressed ground flaxseed, alfalfa powder, whole egg, kelp powder (brown seaweed), brewers yeast, wheatgrass, live probiotics, prebiotics, garlic.). I bought these from the RSPCA shop.

        • Pet Food Reviews (Australia) February 19, 2022 at 4:43 pm

          Generally I find Big Dog very reliable. Natures Goodness on the other hand… I can’t say I find the manufacturer to be “high standard”. They also make Woolworths Baxters and Ivory Coat, which have no end of concerning consumer issues, which I suspect occur on other brands by the manufacturer.

      • Thank you!! How do I PM you?

  3. G’day, we have a new Border Collie X Smithfield pup, 13 weeks old. We’ve been feeding him a cook up of Turkey or Beef mince with pumpkin, broccoli, boiled eggs, rice or couscous. From what I’ve been reading it sounds like we should stop cooking the meat and leave it raw, drop the rice component and replace that with a handful of high quality dry food. Does this sound pretty right?
    Love to hear anyone’s thoughts.

    • Reply
      Pet Food Reviews (Australia) February 4, 2022 at 6:24 pm

      Hi Todd, for feeding raw / raw meaty bones I highly recommend Work Wonders by Tom Lonsdale which will give you excellent information and reassurance. Feeding raw does have some consideration and requirements for organs as well as breast meat, and personally I see value in adding fresh veggies and fruits in moderation. Honestly, I would say feeding a decent raw diet will always be better and likely more cost effective than any commercial dog food, but does take consideration and more time in preparation.

      There’s a fantastic Facebook group The Australian Raw Feeding Group – there are no silly questions and that’s a great community for gathering information.

      Personally I feed my dog a mixture of commercial dog food (for convenience) and a variety of fresh and raw ingredients.

  4. So, my doggo has been fed Ziwi Peak for a long time. The vet recently told me that because of the crumbly nature of the food, it’s causing a quickened build up of plaque. I’m trying to train doggo to let me brush his teeth but he gags, even when using a finger tooth brush. It’s been months of very gradual and slow training with the help of a trainer, and no joy.

    The vet has, of course, recommended either Royal Canin or Advance dental food. He’s apparently missing the action of crunching his food, since ZP is crumbly and he can swallow it pretty quick.

    I’m happy with what I’m feeding my guy. ZP is up there with the best foods, right? My vet has told me ZP contains “too much meat” and not enough grains, etc.

    There’s so much conflicting information and vets really add to the confusion. I was wondering if you had any recommendations for foods that might help reduce the build up. He’s only two and he had to undergo anaesthetic for dental cleaning. We don’t give him bones as we aren’t sure what kind to give him. Maybe that would help?

    • High meat foods are our pets both cat and dogs most important foods. Adding non species appropriate foods like grains and certain carby starchy veggies is the opposite of what they should be getting.

      If your unsure of what’s best in terms of bones ask here. Fresh Food Feeding For Dogs-Kibble Feeders Welcome! 

      Or here. The Australian Raw Feeding Community

      Facebook groups, which when I linked my post got stuck.

      Don’t mention kibble at all on the first one your post will be deleted and you’ll get muted.

      Essentially write what breed of dog, size, chewing habits and people will help you out.

      I wouldn’t suggest any alternatives as people tend to know better I’ve seen than random Google searches.

      I feed my two a high meat diet consisting of mainly air dried and some kibble and freeze dried toppers.

      Mine can’t have very many bones or much of anything to munch on daily without being sick. So I brush their teeth instead.

    • High meat foods are our pets both cat and dogs most important foods. Adding non species appropriate foods like grains and certain carby starchy veggies is the opposite of what they should be getting.

      If your unsure of what’s best in terms of bones ask here. https://www.facebook.com/groups/rawandfresh

      Or here. https://www.facebook.com/groups/rawfeedingaustralia

      Don’t mention kibble at all on the first one your post will be deleted and you’ll get muted.

      Essentially write what breed of dog, size, chewing habits and people will help you out.

      I wouldn’t suggest any alternatives as people tend to know better I’ve seen than random Google searches.

      I feed my two a high meat diet consisting of mainly air dried and some kibble and freeze dried toppers.

      Mine can’t have very many bones or much of anything to munch on daily without being sick. So I brush their teeth instead.

    • Reply
      Pet Food Reviews (Australia) January 19, 2022 at 2:48 am

      My question to your vet would be whether wheat gluten should be the significant ingredient in a canine diet. Or corn and rice for that matter. These make up the bulk of the Royal Canin dental product they’ve recommended to you!

      I just googled “What in Royal Canin Dental reduces plaque” and apparently it’s the abrasive texture and shape of the kibble itself. It makes you wonder why Royal Canin don’t use the same style kibble for all their diets!

      Sadly no commercial dog foods really address dental health, and it’s a clear problem when you speak to vets who understand periodontal disease.

      Personally I feed my dog and cat raw meaty bones. The gnawing and chewing naturally cleans their teeth, and this is the reason cats and dogs in the wild have much better dental health than domestic pets. As a caution you should only feed bones appropriate to the breed and eating habits of your dog, and always raw. Work Wonders is an excellent book on the subject by an Australian dental vet.

      If you’re unsure of bones then brushing is the next best thing, or treats like dear antlers are great for chewing. There’s info on this page – actually a ZiwiPeak treat!

      As for ZiwiPeak – yes, it’s soft, but at least it’s made from ingredients beneficial to your dog. I find it ironic when vets recommend dry kibbles made largely of high-carbohydrate grains, when we know fully well carbohydrates turn to sugars, and sugar rots teeth. Or maybe I’m just radical!?

  5. Vets are trained in PET FOOD NUTRITION not CARNIVORE NUTRITION. But luckily, Dr Franics Pottenger (Medical Doctor) has already done an animal feeding experiment for the vets. Pottenger’s famous 10 YEAR Cats-Diet Study (1932-1942) used 900 x cats over 3 generations of cats using (1) RAW MEAT and (2) RAW MILK vs. COOKED fed cats. Guess which diet produced the healthiest cats after 10 YEARS? The answer is on u-Tube “Pottengers Cats-Diet Will Effect Future Generations”.

  6. Thanks for sharing. Glad you shared your findings. I wish every cat or dog owner thought about this. Unfortunately people make this discovery when it can be too late for their pet. What I found over time, you must educate yourself. It’s not that hard, but takes time and dedication. xx

  7. We have a 9 year old golden retriever in excellent health generally. However he was recently diagnosed with a mask cell tumour on his right flank. Fortunately it had not spread and has been removed.
    Do you have an opinion on what food would be best for him now. He’s always had dried Royal Canin in the past. Grateful for any advice.

    • Reply
      Pet Food Reviews (Australia) March 19, 2015 at 1:12 am

      Hi Judy, if the tumour has been removed and he’s in good health then any good diet should be suitable. I have to recommend you take advice from your vet in a situation like this, but generally to help prevent tumour growth and maintain health you need a diet low in carbohydrates (especially high GI carbohydrates as they fuel tumour growth), decent meat proteins and fats, and fish oils for omega fatty acids. Supplements might be an additional option, for omegas, vitamin D, and anti-carcinogenics like green tea extract.

  8. i have been feeding my great dane pups on giant breed advance dry food and now learn it doesn’t even rate in the best food list. very disappointed and am now being recommended hills science and according to the review on this web that also doesn’t rate in this list . i have read so many articles and blogs and breeders reports and vets reports and still i can not find an agreed best quality dry food. I get that it depends on many variable and how your dogs respond etc but blimey this is hard work. the debates between raw foods and not, soaking kibble and not, too much protein is apparently not an issue now its more about getting calcium to potassium levels right, one person swore by their Paleo diet, and one breeder even said she even fed her danes ice cream and chocolate all their lives with no consequence, seriously! some sites said vets aren’t up on the latest research so don’t trust them follow what your breeders recommend. Well my breeder fed one dane initially on pre soaked adult optimum , and the other breeder weetbix. Do i trust that !!!! i think not.

    • Reply
      Pet Food Reviews (Australia) March 11, 2015 at 12:24 am

      Ha ha, I fully understand Karen. There’s a huge amount of conflicting information and opinions in the world today, especially with the internet. With Great Danes you need to be especially careful as they’re prone to joint problems so need a decent food as a puppy. With Raw you need to be very careful you cater for all nutritional requirements (more info here). I believe the key is variety – us humans have a varied diet, why shouldn’t dogs? There’s some very decent puppy formulas out there, such as Canidae Pure Foundations, Earthborn Holistic Puppy, Ivory Coat Puppy… perhaps try some of those as a base diet, and throw in some human grade meats as and when you can (leftovers from dinner).

  9. i have three dogs, english staffy 3 years, maltese x shi-tzu 2 years and maltese x shi-tzu 15 years. i currently feed them nutro natural choice with a small amount of human grade meat (chicken wings or beef mince). After reading your reviews on nutro im looking to change biscuits but not sure which ones to get. my staffy has a mild allergy and am doing what i can to treat it but it seems to be seasonal so my vet thinks it may be a kind of grass allergy, but none the less am trying to find a food with low allergy ingredients. im looking at canidae all life stages as it seems to be the most affordable from my supplier (pet circle which i highly recommend). is there any others that would be suitable also for around the same price. pet circle will deliver to my house a 20 kg bag for $110. Your thoughts would be greatly appreciated

    • Reply
      Pet Food Reviews (Australia) March 11, 2015 at 12:30 am

      If your Staffy is suffering a seasonal allergy then I agree it might be a grass allergy – something in your garden perhaps, or local park? Any grain-free food might help if that’s the case, as it’s more likely a grain/grass allergy than meat allergy.

      Canidae are a good brand so I can’t argue with that. I believe Pet Circle sell Ivory Coat which is a relatively new Australian made food, and a manufacturer I’ve been very impressed with.

  10. I have just bought a German shepherd puppy from a breeder who was quite passionate about the raw food diet, and which I thought was a good idea but also thought it would be a difficult thing to correctly guess what my puppy should be eating because nutrition is so important to growth, I took my puppy (Atlas) to the vets as recommended by the GSDCV and the breeder and was told that i should switch him to a dry puppy food, The vet had royal canin, the dog shop had black hawk and the other place i looked had the hills science diet…How do I really know what to feed him to ensure proper growth?

  11. I’d like to see more facts about what information vets do actually receive about nutrition, and whether it is different in the USA vs Australia and whether it varies according to different courses taught at / in different universities.
    For Example , we have a couple of excellent vets here promoting and communicating the benefits of raw wholesome food such as Dr Tom Lonsdale (http://www.rawmeatybones.com) and ‘Dr Bruce’ from Vets All Natural. I’ve also read spirited disagreement in some websites about this issue (eg Danielle Steenkamp DVM in the Raw Feeding Community disagreeing )
    There’s no doubt that Lonsdale, appears to have been attempting to counter the pet food company- dominant influence and not getting anywhere… His articles and history make for sad reading.
    If it is true (I’m not fully convinced) it would appear akin to McDonalds and the like subsidising nutritional teaching of paediatrics…

  12. I grew up on a farm and breeding Ridgebacks was my gran’s passion and paying hobby. They took many ribbons. These show and sought after Sires, Bitches or pets for some were fed on porridge and a stew made of chuck, garlic and spinach. They didn’t have fleas or ticks and were very healthy!
    I’ve had show siamese cats that lived on fresh meat and chicken, cubed and frozen in plastic bags plus a few spoons of Pampers Chicken.
    They nibbled on green grass, a piece of biltong, a few Whiskas Chicken dry food pellits now and again. All my cats were stunning, sleek and disease free and lived till 17-21 years. Dry food was a nibble not their main meal.
    I find it hard to believe that commercial food can outshine natural food for flesh eating animals.

  13. hi there, I’ve often wondered the same thing because nutritionally I don’t find Science diet to be the supreme. Yet, many vets don’t seem to mind recommending it. I am a big believer that whatever is most natural, in its whole form, is better – obviously nutrition is about a combination of natural forms to achieve the ultimate diet. On top of this, we find many vets recommending dog food brands that are absolute rubbish, such as a particular Australian veterinarian recommending supercoat! To be honest, I think it all goes back to what they were taught, exactly how you say, the vet science course only includes 6 weeks of animal nutrition – 6 weeks out of the 6 years. Feeding your animals bad quality food may not kill them, but it certainly doesn’t help their health. I have found since educating myself better with pet food quality, that my pets have better digestion (less defacations – what a relief), healthier teeth & gums and healthier skin and coat. So I think there is just a cycle that vets believe science diet is ‘good enough’ to satisfied their nutritional knowledge and since it doesn’t contribute to worsen health (skin conditions, gum, nutritional deficiencies etc) they keep on recommending it. Anyway, very interesting topic for me.

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