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Nutrition Nuggets is the newest offshoot of petMD's Cat Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of cat nutrition.

Foods for Cats with Chronic Diarrhea

July 25, 2014 / (4) comments

When I was a veterinary student, I was taught that dietary fat and gastrointestinal disorders were often a bad combination. The rationale behind this had to do with the fact that fats are often considered to be the nutrient class that is most difficult to digest. Therefore, it’s not too surprising that many of the diets recommended for cats with digestive disorders are relatively low in fat.


I’m not sure what the foundation for this recommendation is. Perhaps some of the underlying facts were “borrowed” from human or canine physiology, but research casts doubts on the “fat as boogeyman” theory …  for cats with chronic diarrhea, at least.


Scientists divided 60 cats with chronic diarrhea into two groups. One group was fed a low fat diet (24% of calories) and the other a high fat diet (45% of calories) for six weeks. Over that time, the owners kept track of the consistency of the cats’ feces. They used “an illustrated fecal score chart ranging from 0 (very watery) to 100 (firm and dry).”


According to the researchers:


Fecal scores improved significantly, with 78.2% of cats improving by at least 25 points on the 100-point scale or having a final fecal score of at least 66. Over one third of the cats developed normal stools. There were no differences in clinical responses between the diets. Clinical improvement was noted within the 1st week, and maximized within 3 weeks.


Interesting. So it appears that dietary fat content is not all that important of a consideration when it comes to improving chronic diarrhea in cats. So why did cats eating both high and low fat diets get better in this study? I think it’s because both the high and low fat diets were highly digestible.


Digestibility is a term that gets thrown around a lot in pet nutrition circles, but its actual meaning is not always well understood. Simply put, the portion of a food that is digestible is that which is absorbed into the body. The indigestible parts of the diet are eliminated from the body in the feces.


Pet food manufacturers can put a number to digestibility through feeding trials. For example, if a cat eats 50 grams of food per day and produces 5 grams of poop per day she is absorbing 45 grams of the food into her body.


45 grams/50 grams x 100% = 90%


This food is 90% digestible. (We’re ignoring water for the sake of simplicity, which is fine as long as we don’t try to compare dry and canned foods.)


You will not find actual numbers for digestibility on pet food labels, but if you call the manufacturer, they should be able to give them to you. Digestibility percentages of around 85-90% are a good starting point for cats with chronic diarrhea. Alternately, look for the terms highly digestible or low residue on the label (you’re most likely to find them on prescription diets). Unlike many phrases you find on bags and cans of cat food, these actually mean something.


Dr. Jennifer Coates



Effect of diets differing in fat content on chronic diarrhea in cats. Laflamme DP, Xu H, Long GM. J Vet Intern Med. 2011 Mar-Apr;25(2):230-5. 


Image: Valeri Potapova / Shutterstock


Comments  4

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  • Change protein in diet
    07/23/2014 10:56am

    I am a UK vet with an elderly cat who suffered from chronic diarrhoea. I am a great believer that many of these cases DO NOT need expensive blood and faeces tests in the first instance (unless there are other signs of hyperthyroidism for example). If your cat is otherwise healthy, try a planned programme of trial diets. Note - any change needs to be made gradually.
    In my opinion, most of these cases are due to PROTEIN allergies so it is no point trying a 'chicken flavour' diet as it will probably only be 4% chicken and the rest listed as the dreaded 'meat and animal derivatives' which could be anything. You can home cook a diet of protein with an equal amount of rice but, lets face it, most of us like the convienence of dry diets - plus they are better for the teeth. Look for good quality diets where they state 'chicken, fish, lamb, duck ONLY'. Try the one that your pet has had LEAST of in its life - introduce slowly and only give it that - although you can suppliment it with home cooked protein of the same type. Try it for 4-6 weeks. If the bouts of diarrhoea haven't improved, gradually switch to another protein source. Obviously, if your cat gets really ill in himself or if there is severe weight loss - go to your vets.
    Incidentally, I did pay for a full blood work up and faeces test on my cat - all of which was unremarkable. I gave him some probiotics - Protexin for a short period. The third diet I tried - James Wellbeloved senior fish and rice - worked. Three years later, he maybe has diarrhoea once every 3 months, is happy and healthy and I did NOT use any antibiotics or steroids.
    Hope this helps!

  • Diarrhea Thoughts
    07/25/2014 09:45pm

    In my opinion, something is causing the diarrhea and I agree with franthevet that allergies could very well be the culprit (if it's not one of the comment causes such as hyperthyroidism).

    Luckily chronic diarrhea isn't something with which I've had to deal, but Fluffy would be at the vet many times to find the cause. And, when really frustrated, I'd be calling on specialists.

    As an aside, if Fluffy has been ill, is it possible that the gut has lost the enzymes necessary to digest food properly? Might acidophilus help?

  • 07/25/2014 09:46pm

    Uh, that's COMMON causes, not comment causes. Sure wish there were a way to edit a comment after it posts and fix typos!

  • 07/26/2014 08:00pm

    cheers old broad - I never even noticed the spelling mistake. I did try acidophilus but Murphy is really hard to tablet and wouldn't take food with the capsules opened and sprinkled on which is when I bought the protexin paste and forcibly syringed him ( complete with a few gouges out of my hand!). Dietary therapy is sooooooooo much easier