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Top Kibble Myths — Busted!

It's time to expose the leading kibble myths that just won't die, and one that nearly half of pet owners believe could actually harm their pets. Falsehoods aside, discover the canine-approved option that can reduce tartar by 87% in only 20 days.

dry dog foodmyths


  • According to a market survey, pet parents prefer dry pet food over canned food because they mistakenly feel it’s more nutritious, keeps their pet’s teeth clean, and also has a mild smell
  • It’s a myth that kibble helps keep pets’ teeth clean — raw diets, raw bones, and tooth brushing do; and while it’s true that kibble tends to be less smelly than commercial canned pet food, fresh human grade pet food has no offensive smell; it smells like real food
  • Dry pet food, for all its convenience, is difficult to store in a way that preserves its nutritional value and freshness
  • Kibble is also far from ideal for a long list of other reasons, including poor quality, highly refined ingredients, high-heat processing methods, the inclusion of biologically inappropriate grains and/or starches and synthetic nutrients, and lack of moisture
  • For optimal health, feed your pet a minimally processed, high-quality animal protein and healthy fats and fiber, with low starch content

Editor's Note: This article is a reprint. It was originally published April 25, 2021.

A few years back, market research firm Packaged Facts conducted a survey of pet owners to determine why they buy kibble vs. canned food for their cat or dog.1

“… pet parents bring a set of preconceptions and preferences to the decision between dry and wet pet food that frame product choices well before brand reputation, specialty formulations, or product claims or introductions kick in,” wrote Tim Wall in a May 2017 article for online journal
“Among these, two assumptions and one preference help give dry pet food a strong advantage, in keeping with its share of pet food sales.”2

According to the survey results, the two assumptions are that kibble is healthier and provides oral hygiene benefits. The preference is for relatively odorless pet food over products with a strong smell (e.g., canned dog and cat food).

If many pet owners are concerned first and foremost with less smelly pet food, this isn’t entirely surprising, since it was convenience that made kibble so appealing in the first place, similar to the popularity of processed and fast food for humans.

And it certainly doesn’t help that pet food manufacturers spend huge amounts of money marketing their hyper-refined, overcooked formulas as “healthy,” or that the majority of veterinarians promote the stuff as being the clear choice to feed, among all the choices in the pet food industry.

In my experience, as more and more pet parents open their eyes to the tremendous health benefits of feeding fresher, minimally processed, species-specific diets to their animal companions, low-odor convenient kibble takes a backseat to low-odor human-grade, nutritionally balanced fresh food.

The Myth That Will Not Die: Kibble Cleans Pets’ Teeth

Dry (extruded) diets have been promoted as helping to keep pets’ teeth clean, but this is utter nonsense. Kibble is no better for your dog’s or cat’s teeth than crunchy human snacks are for your teeth. It would never occur to you to eat a handful of peanut brittle or granola to remove plaque and tartar from your teeth, and the idea that dry food keeps your pet’s teeth clean is just as silly.

However, diet certainly plays a significant role in the development of tartar on your pet’s teeth. Wild dogs and cats have strong, healthy teeth partly because they eat and chew raw meaty bones. Raw diets — even prepared, ground raw diets — help control tartar.

Raw ground bone is a gentle dental abrasive, acting like fine sandpaper when chewed, which helps remove debris stuck on teeth. Biologically appropriate fresh food diets are naturally low glycemic, so there’s no sugary residue left on your pet’s teeth after a meal, unlike kibble.

For dogs and cats, chewing also plays an important role in removing plaque and tartar from teeth. In one study, raw bones reduced tartar by a whopping 87% in 20 days!3 Even though there are plenty of toys and food products on the market that can be of some benefit, raw bones are really the most natural (after often cheapest) option for dental and emotional health; most dogs love them.

There are two categories of raw bones; edible bones and recreational bones. It’s important both categories are offered raw, because cooked bones can splinter and do serious damage to the gastrointestinal (GI) tract.

The size and type of bone depends on the size of your pet and whether she’s such an eager chewer that she risks injuring herself or even breaking teeth. Click here to learn the rules of feeding raw bones if you’ve never offered them to your dog.

Your dog should always be supervised when she’s working on a bone for dental health to minimize the risk of choking or tooth damage, and raw recreational bones should be refrigerated between chewing sessions.

With a gentle hand, patience and persistence, most pet parents can teach their dog or cat to tolerate daily tooth brushing, which is the ideal way to ensure tartar doesn’t form on tooth surfaces. One of the secrets to successful tooth brushing is to progress slowly and gently, allowing your pet to trust the process and adapt at her own pace.

If your pet is highly resistant to having her teeth rubbed or brushed, there are products available that when applied to the teeth go to work to break down plaque and tartar without brushing. However, the more rubbing and brushing she’ll allow and from an early age, the more quickly you’ll see results, and the easier it will be to maintain her oral health.

Another Myth: Kibble Is Better Nutrition for Pets

Based on the survey results, nearly half of pet owners at least somewhat agree that dry foods are healthier than canned pet food. For purposes of clarity, when I refer to dry food here, I’m referring to extruded kibble, not minimally processed freeze-dried or dehydrated pet food, which in theory is also “dry food.” The reality is that ultraprocessed feed-grade kibble is one of the least healthy pet foods on the market today.

Many pet parents who feed kibble love the simplicity of buying it in bulk and simply pouring it into their dog’s or cat’s bowl at mealtime. But one of the many problems with this convenience pet food is it doesn’t store well.

No “complete and balanced” pet food exists that is also shelf stable. One example: As soon as a bag of kibble is opened, important dietary fats in the food start to go rancid, and long-term consumption of rancid fats can obviously negatively impact your pet’s health.

The “best by” date on your bag of kibble is how long the food lasts before the bag is opened. Once the bag is opened, it should immediately be stored in the freezer and fed within a month to prevent the negative effects of oxidation that occur in the food from being passed up the food chain.

Also, because kibble is processed multiple times and at extremely high temperatures, effectively killing all the nutrition in the food, manufacturers assume the finished product contains no micronutrients. That’s why the final production step involves spraying on a nutrient mix (and a palatability enhancer to make pets want to eat the stuff).

The nutrient mix contains cheap, feed grade vitamins, including metal oxides (check the label for ingredients such as “zinc oxide,” etc.) and sulfates (“copper sulfate,” etc.) that speed the oxidation of fats, ultimately resulting in rancid fats in a formula that may or may not be entirely safe to feed as little as a week after it was opened.

There’s also significant potential for opportunistic bacteria and mycotoxins in dry pet food, and the longer the kibble is stored, the greater the risk to your pet and anyone in the family who handles the food.

And as if all that wasn’t bad enough, storage mites can also proliferate in dry food. These tiny mites start out in grain silos and from there find their way into dry foods like cereal, grains, and kibble. Pets can develop a hypersensitivity to storage mites, resulting in itchy inflamed skin, hair loss, and recurrent ear infections.

If you must feed dry food, don’t buy in bulk. Instead, purchase enough for 30 days at a time. Check to make sure the food isn’t near (or past) its use-by date, and also ensure there are no tears in the bag. Since rancid fats are worse than no fats, I recommend buying formulas that do not contain added essential fatty acids (EFAs). Instead, add them fresh at mealtime. Sustainably sourced krill oil is an excellent choice.

Dry food that sits in a warm or humid environment presents a greater risk for rancidity, bacterial and fungal growth, and other problems, so it’s best to store most of it in the freezer and remove just enough for one or two meals at a time. Kibble kept at room temperature (not recommended) should be in an airtight container that is washed frequently with detergent and hot (not warm) water. Never store kibble in a warm environment, like a garage.

When you open a new bag of kibble, don't pour the remainder of the old bag into it to avoid potential contamination of the new food. If you transfer the food to another container(s), you might want to write down the brand, variety, lot number, and any other pertinent information in the event of a recall. I also recommend disposing of empty pet food bags immediately outside the house.

Do You Really Want Your Dog or Cat Eating This Stuff?

While most kibble is formulated to meet the basic nutritional requirements of dogs and cats, it certainly doesn’t provide optimal nourishment for the long haul, just as a lifetime of cereal isn’t an ideal sole food source for human kids.

I have several issues with dry pet food, but let’s start with the quality of the raw ingredients. If your pet food’s website doesn’t use the term “human grade” throughout, the food you’re feeding is made from ingredients that failed human food inspection or were deemed inedible for humans.

Rendering plants create meat and bone meal from a variety of dubious sources, for example, parts of cows that can't be sold for human consumption, including bones, the digestive system, the brain, udders, hide and more. The vast majority of pet foods are made with ingredients rejected by the human food industry, meaning they’re feed grade.

An FDA compliance policy allows for feed grade pet food to include the carcasses of diseased animals, expired grocery store meat (including the plastic and Styrofoam packaging), road kill, zoo animals and dogs and cats that have been euthanized. Here’s a stomach-turning description of the process of spinning these raw ingredients into pet food from Slate:

“This material is slowly pulverized into one big blend of dead stuff and meat packaging. It is then transferred into a vat where it is heated for hours to between 220 [to] 270 degrees F. At such high temperatures, the fat and grease float to the top along with any fat-soluble compounds or solids that get mixed up with them.
Most viruses and bacteria are killed. The fat can then be skimmed off, packaged and renamed. Most of this material is called 'meat and bone meal.' It can be used in livestock feed, pet food or fertilizer … There is essentially no federal enforcement of standards for the contents of pet food.
… Indeed, the same system that doesn't know whether its main ingredient is chicken beaks or Dachshund really cannot guarantee adequate nutrition to the dogs that eat it.4

There are a few kibble companies that pride themselves on using human-grade meats and no imported nutrients, so if you must feed kibble, I suggest making sure you’ve done your homework to identify whether the food is food grade or feed grade. Visit the company’s website, where they should brag about the sources of their raw materials. However, there are still other issues with feeding ultraprocessed foods like kibble, in general.

More Problems With Kibble

The majority of dry pet food is a blend of poor-quality meats, agricultural leftovers, byproducts of the human food industry and synthetic vitamins and minerals. In addition, most kibble contains a large amount of high glycemic corn, wheat, rice or potato — grains and starches that offset critical nutrients found in fresh meat and create metabolically stressful insulin, glucagon and cortisol spikes throughout the day.

In fact, many popular grain-free diets have a higher glycemic index than regular kibble due to the excessive amounts of starchy ingredients (e.g., potatoes, peas, lentils, tapioca) used in the formulas. As we know, carbs break down into sugar, which fuels degenerative conditions such as diabetes, obesity and cancer.

In the last 50 years, we've learned the hard way that feeding ultraprocessed, fast-food diets to our family has negative health consequences. More and more research demonstrates that feeding large amounts of highly refined foods and biologically inappropriate diets to pets does not create health. In fact, chronic inflammatory and degenerative diseases in dogs and cats are at epidemic levels, and the problem can be traced in large part to diet and lifestyle.

To make matters worse, the poor quality proteins and fats used in most kibble, when processed at high temperatures, create cancerous byproducts, including Advanced Glycation End Products (AGEs) and Advanced Lipoxidation End products (ALEs) that have been linked to early aging and a myriad of serious and common degenerative conditions.

The meat that goes into extruded pet food is put through at least four high temperature cooking processes, leaving the digestibility, absorbability and overall amino acid content highly questionable.

The low moisture content of dry food is also problematic, especially for cats. Dry cat food provides only about one-tenth the amount of moisture cats receive from prey animals, living foods and even commercial canned diets, which puts significant stress on their kidneys and urinary tract. Dogs also tend to become excessively thirsty when fed a dry diet.

The carb-heavy nature of dry food, along with overfeeding, is also a significant factor in rising rates of pet obesity.

Ready to Feed Your Pet a Truly Nutritious Diet?

If you’re a regular visitor here at Mercola Healthy Pets, you know that I recommend pet parents ditch dry food altogether and instead feed a nutritionally optimal, species-specific diet, which means food containing high-quality animal protein, moisture, healthy fats and fiber, with low to no starch content.

A nutritionally balanced raw or gently cooked homemade diet is my top choice for pets, but you should only attempt this if you're committed to doing it right. If you don't want to deal with balancing nutrient levels at home, a great alternative is to feed a well-formulated, nutritionally complete commercially available raw food.

A freeze-dried/dehydrated diet is second best, along with commercial gently cooked diets, with many brands delivering right to your door. Human-grade canned food is a mid-range choice but can be hard to find and is the most expensive food on the market.

As you strive to freshen up your pet’s bowl, be sure to incorporate a variety of fresh foods from your refrigerator into your pet's diet, too, as meal toppers or treats. Diversifying your pet’s real food intake means more food-based antioxidants, polyphenols and phytonutrients are available to benefit your animal’s microbiome and body.

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