Prescribed vs. commercial: If it’s dry food, think twice

Update: I wrote this article six years ago, and my concerns still apply. However, here’s an interesting update: A variety of big pet food manufacturers touting “prescription” pet foods and commercial enterprises that support them now face a class action lawsuit, which asserts that the ingredients in their food do not warrant a prescription.

Hill’s has come out with yet another prescription diet, and this one claims to address any and every kitten and cat concern.

As with all of Hill’s products the foods are chock full of ingredients no carnivore would be caught eating.

Does kibble ever qualify as healthy or natural?

First of all, it’s dry food. More and more dry food is being fingered as causing diabetes, obesity, liver disease, pancreatitis, and urinary tract problems.

Secondly, to facilitate the extrusion process, it’s full of grains, in this case two permutations of corn, plus brewer’s rice. But the grain-based ingredients are “split,” which appears to minimize the amount. That’s a classic kibble caper. Speaking of corn, Hill’s posts an article titled, “Corn – An Amazing Grain,” which says, in part:

Corn has been called a filler, a “hot grain” and a major cause of allergies. The facts are, corn is NOT a filler (an ingredient providing no nutrition) as it supplies many essential nutrients. In pets, corn is NOT a hot grain (causing gastrointestinal upset) because it is safely and easily digested.

As far as meat is concerned, that is in the form of chicken by-product meal. An inferior source of protein, it’s defined by the American Association of Feed Control Officials (AAFCO) as “the ground, rendered, clean parts of the carcass of slaughtered chicken, such as necks, feet, undeveloped eggs and intestines, exclusive of feathers, except in such amounts as might occur unavoidable in good processing practice.” In terms of other meat- or poultry-based ingredients, there’s “chicken liver flavor,” which is not recognized by AAFCO; however, I read that as waving a piece of liver over the batch of food and not an adequate source of protein.

For kittens, the food is supposed to cover immunity, weight management, bladder health, digestion, and skin and coat. For adults, oral health is substituted for immunity (Says the web site, “Clinically proven kibble technology naturally scrubs teeth clean like a toothbrush reducing plaque & tartar buildup.”) Its protein is listed at 42 percent (dry matter) as opposed to 33.8 percent for the adult version. Of course, Hill’s touts “high quality ingredients” in both formulas.

Then there’s powdered cellulose, which replaces high quality ingredients in weight loss diets.

Finally, as is typical of all commercial pet foods, all the vitamins and minerals that are destroyed when the ingredients are processed to death are added back in, along with DL-Methionine (a urinary supplement) and Vitamin E for skin and coat.

Elizabeth Hodgkins, DVM, JD, comes down hard on veterinary diets. She says they are no better than regular commercial foods that are made from salvaged. She says they are not tested like drugs and do not have the curing properties The former director of Technical Affairs at Hills Pet Nutrition, Hodgkins adds that these foods are the result of flawed, marketing-driven science.

A few years ago Hill’s came out with its Nature’s Best formula. My heart skipped a beat for a moment. Until I read the ingredients list, that is. Chicken and chicken meal are accompanied by four different grains: corn, rice (but it’s brown rice!), oats and barley. I suppose the various fruits and veggies also capitalize on the natural theme.

Not surprisingly, Iams and Purina have also jumped on the Healthy/Natural bandwagon and their ingredients list is similar.

Top ingredients for Iams Healthy Naturals with Natural Chicken include: Chicken, Chicken By-Product Meal, Corn Meal, Brewers Rice, Ground Whole Grain Barley, Chicken Meal, Dried Beet Pulp, Dried Egg Product, Natural Flavor, Sodium Bisulfate, Potassium Chloride, Fish Oil (preserved with mixed Tocopherols, a source of Vitamin E), Animal Fat (preserved with mixed Tocopherols, a source of Vitamin E), DL-Methionine, Dried Apple Pomace, Dried Carrots, Brewers Dried Yeast, Fructooligosaccharides, Dried Peas, Calcium Carbonate, Choline Chloride, Dried Spinach, Dried Tomatoes.

Fruits and veggies add a designer touch to cat food.

For Naturals by Purina, the list includes: Chicken meal, corn gluten meal, soybean meal, brewers rice, animal fat preserved with mixed-tocopherols (form of Vitamin E), corn meal, chicken, salmon, powdered cellulose, ground whole wheat, soybean hulls, malt extract, brewers dried yeast.

Not much different from the veterinarian-prescribed food. Except for the veggies, which, while a nice touch, aren’t nutritionally vital. And look how far down on the list chicken and salmon are found.

AAFCO has defined the term “natural” when used in pet foods as the following:

A feed or ingredient derived solely from plant, animal or mined sources, either in its unprocessed state or having been subjected to physical processing, heat processing, rendering, purification extraction, hydrolysis, enzymolysis or fermentation, but not having been produced by or subject to a chemically synthetic process and not containing any additives or processing aids that are chemically synthetic except in amounts as might occur unavoidably in good manufacturing practices.

An exception was made for the synthetic vitamins and minerals that must be added back after the food is processed (albeit, to death…). That list is as long as the list of “natural” ingredients.

And the term “healthy?” It’s all in the eyes of the marketing departments. Would they dare not say their food is not healthy?

So before you accept that bag of kibble from the vet’s office, do some research. Check out my comprehensive list of nutrition resources and decide for yourself what is best for your cats.


About ExclusivelyCats
Sally Bahner is an expert in all aspects of cat care: Writer, consultant, speaker, instructor.

6 Responses to Prescribed vs. commercial: If it’s dry food, think twice

  1. Thanks for this article, Though I think hills diets are far from perfect, they mostly are very good are doing what they say they will, wether the food is to be low fat, highly digestible or high energy. I also think some diets like the renal formula would be very difficult to make from home. Some people might be critical of hills for being a mega company, but I think it is useful to remember that it started with one vet determined to make a difference to the diets of pets. I would support any person that would make a better range of commercial vet diets. Of course pet foods are not tested like drugs would be, people do not want them to be, Look what happened to Iams when PETA started to look into their testing. PETA puts things out of all proportion. Also Chicken by product would have a large range of quailty, in premium food it would mostly be liver and kidneys, and never feet.
    Cheers and all the best.

    • I have a cat has kidney disease and she eats raw food that I make or canned classic Fancy Feast (low carb). I control the phosphorous with a binder and she is also on Calcitriol which has slowed her kidney disease. Water is a kidney cat’s best friend and dry food is a species inappropriate choice and detrimental to a kidney cat’s health (low moisture content, inappropriate ingredients). There is no research to uphold the pet food companies’ assertion that low protein is helpful to kidney disease. The “studies” that were the genesis of the low-protein theory were done on *rats* and *dogs*…not cats.The studies were then *falsely interpreted* and *misapplied* to cats, who have completely different metabolisms, evolutionary diets, and bodies than rats and dogs. The *only* reason there is “low protein” products for cats is b/c the founder of what became Hill’s developed a low-protein diet for a dog in the 1940s. It made $$$. The entire “prescription” product line evolved from there. The only people who are going to pay for a “study” demonstrating the benefits of low protein on cats are feed mfrs selling low-protein products.
      I will never feed my cats dry food ever again now that I have learned the truth!

  2. Robin Olson says:

    Bravo!!!! I’ve been shouting from the rooftops to all my readers NOT to feed kibble to their cats, EVER..or their dogs, for that matter. Those diets are based on GREAT MARKETING, that’s it-not great nutrition. The pretty picture on the bag should be considered false advertising! I’m so glad to see other folks writing about the dangers of dry and reminding cat lovers that cats are obligate carnivores who get their energy from PROTEIN not carbs. To feed them something they can’t even digest..does that make any sense? NO!

    If we keep talking about this topic, sooner or later the Big Pet Food manufacturers are going to have to realize we’re on to their BS and we want and demand better for our companion animals.

  3. Amy says:

    Felines as a whole are OBLIGATE CARNIVORES, Mr O’Donoghue. That didn’t change just because we domesticated a few and brought them inside to live with us.

    There is NO dietary reason Felis catus need grains, beyond what their prey – AHEM herbivores – would have in their own belly at the time of being killed and eaten.

    Chicken by-product meal has had whatever miniscule nutrients cooked out of it, so serves no purpose to be included beyond it is CHEAPER than whole protein, which is the golden rule for commercial pet food manufacturers.

    Most commercial diets on the market today are suitable for domestic canines and other OMNIVORES, including humans. NOT CARNIVORES.

  4. Wised Up says:


    Just to clarify the powdered cellulose:

    “By and large, the cellulose used in petfood applications is derived from pine trees. The ingredient starts its journey in the pulping mills, the same mills used to produce paper. The pulp is…” ….

    All those “prescription” diets do is dehydrate a species with an already naturally low thirst drive enough to prompt it to drink even more water. Just look at the ingredients. Anything would get dehydrated eating that stuff — unless it’s a termite!

    Michael, it is a conflict of interest, period. Again, just look at the ingredients. Any Veterinarian well-versed in nutrition with no conflicts of interest (generous funding and incentives) would know what to feed a carnivorous species. It’s common sense a cat can’t chew, grind, rotate its jaws. No WONDER they throw up all the time.

    • Hello Wised Up:
      I did a bit a research regarding powdered cellulose in writing this article and the one I cited seemed to be the most accommodating. Indeed, my knee-jerk reaction to cellulose in dry food has always been wood/trees. It’s a matter of convincing one person at a time. I keep running into a woman who had one and now two diabetic cats. They get insulin, and yes, dry food. She knows my position, but just hasn’t been able to get beyond what her veterinarian recommends.

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