Stomach Confusion: Can You Mix Kibble and Raw Together For Feeding?

Stomach Confusion: Can You Mix Kibble and Raw Together For Feeding?

To answer the question simply: yes, you can.  Perhaps you’ve heard otherwise, or there are some caveats.  That’s what this article will get into.

*In case you’re wondering, kibble is dry food artificially formed into little brown shapes most people feed their dogs and cats.

(I recently added a video to complement this blog, potentially furthering the discussion, here.  Not conclusive by any stretch, but it does make you wonder if a human, that should have a lower stomach pH than a dog, can digest raw and kibble, does the argument that you can’t mix the two still hold up?)

There are a couple of obvious reasons why you’d want to feed a blend of raw and kibble.  One is transitioning from kibble to raw.  You’re trying to minimize digestive upset while making sure your pet takes to raw by having some familiar food in her bowl.  This is for a very short duration, usually for a week or so.  Some pets have sensitive stomachs.  Doing a transition helps the digestive system adapt to a new food without having to deal with diarrhea or other types of maldigestion.  Transitioning is a common practice.  It’s even done when moving from one type of kibble to another to minimize stomach upset.

Another is expense.  Raw may not be in your budget, but you’re doing what you can to afford the time and/or money required.  You could be stretching the raw meals by adding some kibble to make sure ends meet.  After all, some fresh whole food is better than none at all.  (In reality, some bargain shopping can yield very healthy raw, fresh meals for your pet without the need for kibble, but that’s another topic — read how here for DOG and CAT.)

Mixing raw and kibble does no harm, short-term or long-term beyond the effects of the kibble itself.   Humans have many foods mix all the time: think eating croutons on a fresh salad or a sushi roll that has raw fish and cooked rice.

I think I’m a realist.  I do not support feeding kibble in most cases because there is almost always a healthier solution for the circumstance.  Exceptions do exist.  However, there are extreme absolutists that are vocal when it comes to any kibble in a diet.  A strict and unbending philosophy.  It’s a very black-and-white decision for them: either 100% raw or you’re not feeding your pet correctly.  With that judgement you also get a generous slathering of guilt and pressure, questioning the love you have for your pet.  I’ve heard and seen it many times from the online communities.  There is no reason good-enough in their mind for ever letting your pet eat kibble.

The arguments from the extreme anti-kibble people spread questionable information for the right reasons.  One of their claims is kibble messes with the pH of the stomach, throwing it off, making it difficult to digest raw.  The other is kibble digests so slowly that harmful, toxic bacteria grow in the gut.  Then there’s the one that kibble and raw digest at different rates, which throws the whole digestive system into chaos.  There are probably some more that are on the interwebs somewhere.  All not true and certainly not backed up by science.

Not true because that’s not how the digestion system works.  Dogs, cats, and humans have a similar process.  There isn’t a selector switch in the stomach that detects kibble (or raw) significantly altering the strength of the acid or amount of enzymes released.  If you ate the best salad ever produced with the best ingredients, perfectly designed for your genome, and a Big Mac at the same time, your digestive system would handle it fine.  The same with raw food and the highly processed kibble.  If you’re not use to kibble, or Big Macs, you could feel a little funny (dyspepsia) but your digestive system won’t be crippled.

Digestion is the process of the extracting nutrients from food, shuttling the unlocked nutrition from the GI tract into the body where it is used for energy and tissue growth.  The stomach and small intestine are the major sites of digestion.  The stomach does not absorb nutrients; it releases them from the food, also destroying pathogenic bacteria like salmonella spp, clostridia, campylobacter and E Coli.  The longer food spends in the stomach, the greater the amount of breakdown (which is good).  The entire small intestine is the site of nutrient absorption, not the stomach. Nutrients released from the food are absorbed though the intestinal wall into the bloodstream.  The speed of food flowing though the intestine will impact the amount of nutrients that can be absorbed.  Fast moving nutrients may not be completely utilized.

Once food has entered the stomach the work begins.  Before the first bite of food is taken, stomach ‘juices’ are released into the stomach in anticipation of eating — the body gets ready from the smells and sight of food.  Food arriving in the stomach causes stretching/distention, triggering the release of even more stomach ‘juices’.  Chemical digestion of proteins is initiated by enzymes like hydrochloric acid, pepsin, and lipase and food is liquidized. Hydrochloric acid is the enzyme responsible for denaturing proteins, eliminating bacteria, and converting other enzymes. Pepsin is solely responsible for protein digestion, and lipase, which is only found in the stomach of carnivores (dogs and cats), begins digesting fats.

After being turned into liquid, food begins to leave the stomach into the small intestine. Bile and pancreatic enzymes are critical for the absorption of fats, carbohydrates, and proteins. This is where the majority of chemical digestion takes place.

Finally, food moves into the large intestine. In carnivores, this is where water is absorbed, bacterial fermentation takes place, and feces are formed.

There was a recent experiment focused on seeing what speed raw and kibble were both digested.  Using X-rays and barium (a radiopaque liquid mixed with the food), the researchers were able to follow kibble and raw meals, each fed a couple of weeks apart, through the gastrointestinal tract.  While only one dog was examined, it showed raw digested slower than kibble.  The experiment pretty much laid waste to the blanket statement that “raw digests faster than kibble”. It follows the common knowledge that liquids tend to empty from the stomach faster than solids and carbohydrates pass faster than proteins and fat. (Kibble contains significant carbohydrates.)

When food hits the stomach, it drops into waiting digestive juices.  Then, depending on how much distention, the stomach releases an appropriate amount of juices to manage dilution, so the pH can stay at a high acid level initially.  Dilution (increasing pH) is part of the digestive process.  It happens gradually through the digestive tract.  You wouldn’t want to poop full-strength hydrochloric acid, right?

The stomach has a great design that has served dogs and cats for thousands of years.  One example, when calcium is sensed in the stomach, more acid is released because bones are expected due to the calcium content.  It takes more digestive juices to break-down bones than, say, flesh.  There are more of these ‘sensors’ and feedback mechanisms in the digestive system to efficiently extract nutrients from various diets that animals may have to eat in good times, and non-normal things in bad (like kibble).

It’s important not to conjure a false cause-and-effect, mistakenly attributing digestive disruption of a sensitive stomach because a diet is changed, with feeding raw and kibble together.  There are studies, detailed research on dogs and cats, and humans, giving no indication mixing raw and kibble together creates a toxic brew or digestive challenge.

Mixing kibble and other food-types has been done for decades.  Only recently the trend of avoiding this type of feeding seems to have become popular, fueled by suspect information and passionate emotion.  Studies do show mixing some fresh, raw food with kibble is much better health-wise than kibble alone.  A full raw diet is the best thing you can feed your pet and is the ideal that we should all strive for as responsible pet guardians.  But there are valid exceptions and always things you can do to mitigate feeding kibble exclusively.

As always, consult your vet before making any substantial change to your pet’s diet.

Fetching Foods is a top quality, nutritionally rich raw and gently cooked food for dogs and cats.  It’s made entirely with high-end, human-grade ingredients.  We offer several products including Just Cat, Only Dog, and Custom Meals designed specifically for your dog’s or cat’s unique needs.


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J. W. McINTOSH, N. ANDERSON, H. L. DUTHIE, and A. P. M. FORREST  “THE EFFECT OF AN ADRENAL INHIBITOR (SU 4885) ON GASTRIC SECRETION IN DOGS”  University Department of Surgery, Western Infirmary, Glasgow

Bourreau, J., D. Hernot, et al. (2004). “Gastric emptying rate is inversely related to body weight in dog breeds of different sizes.” Journal of Nutrition 134: 2039S-2041S.

Case, L., D. Carey, et al. (2000). Canine and Feline Nutrition: a resource for companion animal professionals. St. Louis, MO, Mosby, Inc.

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Hand, M. S., C. D. Thatcher, et al., Eds. (2000). Small Animal Clinical Nutrition. Topeka, KS, Mark Morris Institute.

Itoh, T., T. Higuchi, et al. (1986). “Effect of particle size and food on gastric residence time of non-disintegrating solids in beagle dogs.” Journal of Pharmaceuticals and Pharmacology 38(11): 801-806.

Keinke, O., M. Schemann, et al. (1984). “Mechanical factors regulating gastric emptying of viscous nutrient meals in dogs.” Quarterly Journal of Experimental Physiology 69: 781-795.

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