You are all going to think this is my favorite topic. …the reality is, I am passionate about teaching others to be unbiased, well-informed  – good critical thinkers and researchers when it comes to canine nutrition. And as I’ve been emphasizing, carbs are very misunderstood and unjustly feared. Extremes in diet are never wise, and many have totally eliminated carbohydrate in the mistaken belief that they are harmful to dogs. Again I emphasize – which source, how much, and for what dog?

Ok – so last time we saw that all carbs are is energy from plant matter, one of the three groups that provide significant energy in the diet. When we take out carbs entirely, we are using ONLY protein and fat to provide the calories your dog needs to run on. And that can have some unwanted consequences, especially over time or with certain conditions .

We saw – and most know anyway – that carbs are not all the same, that one wellknown division is between simple and complex.  We agreed (at least I think we did) that simple carbs are not good for dogs (or, really, anyone). Complex carbs or polysaccharides (starch and fiber) are not requirements in the sense that an overt pathology will develop in their absence, but they perform important biological functions. I think that’s about as far as we got.

In this installment I’d like to look at fiber; not quite as controversial as starch, most researchers agree that some dietary fiber is an important addition to the diet, it’s been well studied and the types and amounts, while variable from dog to dog , are pretty well understood.


Fiber is defined as” plant material that consists primarily of several forms of carbohydrate…which cannot be broken down to monosaccharide units for absorption in the small intestine”. It’s the part of the plant that is not digested – and it plays an important role in your dog’s health and wellbeing.

Looking at “non-digestible carbohydrates “- in other words, fiber – we see divisions that can help us make the best decision with regard to which type  we want to use. The first classification everybody has probably heard already is soluble/insoluble. The second aspect that pertains to fiber and our decisions about which source and how much to feed, is rate of fermentability. There are other aspects with regard to carbs overall – gluten content, glycemic load, anti-nutrients – but with fiber these two concepts are key.



This one is relatively simple.

Soluble fiber partially dissolves in water, forms a gel as it passes through the intestine and is also highly fermentable. Insoluble fiber does not dissolve in water, and is resistant to fermentation. Sources of soluble fiber include oatmeal and oatbran, seeds such as flax, legumes, apples and blueberries, and psyllium.(Important to note that many soluble fibers are actually a mix; psyllium, for example, which is very helpful for problems such as diabetes and anal gland issues, is 70% soluble and 30% insoluble fiber.)  Sources of insoluble fiber include wheat, barley, brown rice and many vegetables. Both have value but  need to be added according to other factors in the dog’s makeup as well as other considerations in the food sources. For example, wheat and brown rice both contain insoluble fiber, but rice has no gluten, and as we shall see, gluten is a good thing to avoid or at least, minimize. Hence I would use brown rice over wheat, and  squashes over barley. Both provide insoluble fiber in a gluten-free form. Insoluble fiber should represent the  majority fo the total fiber intake for most dogs.

Soluble fiber has it’s role to play too.  Soluble fiber such as psyllium or ground flaxseed helps to  stabilize blood sugar levels. This  is not only useful for diabetics but important for all dogs, that blood sugar levels should not spike dramatically (more on that later). Soluble fiber should not be overfed, but considered as an augment to a largely insoluble fiber presence in the diet, much as one adds probiotics or other supplements to aid in bowel health.  But all  fiber  affects nutrient absorption, soluble more so than insoluble; it also slows gastric emptying which can be therapeutically valuable if the dog is constipated.


As we have seen; non-digestible polysaccharides  ferment in the large intestine, but with varying speed – insolubles like  wheat bran and many grains hardly ferment at all, while solubles like pectin and guar gum, many fruit and vegetable fibers are highly fermentable. Rate of fermentability greatly affects gastric emptying and  too much highly fermentable fiber will usually result in diarrhea. The key thing we look for is fiber that ferments at a moderate rate. Beet pulp is one such fiber and  that’s exactly why it’s in so many dog foods – well, that and it’s cheap. Rice bran is another moderately fermentable fiber with more health benefits than beet pulp offers, and hence it’s a very good choice for the dog who is not allergic or intolerant of it. I sometimes use soaked, well cooked brown rice as a part of the carb and fiber section of of a recipe; less than I used to, but it still has a place. While it’s become popular to think of canned pumpkin as a panacea for diarrhea, cooked brown rice helps many dogs just as well.  Brown rice provides about 215 calories per  cup, and offers 3.5 grams of mostly insoluble fiber; it’s glutenfree, moderately fermentable and a good source of selenium, manganese and niacin as well.   Look for organic sources and wash until the water runs clear; cook softer than we humans like it. We’ll be going much more into detail on all the foods we use to homefeed dogs. Solubility and fermentability are keynotes to understanding fiber, what it can do for your dog, how much to use (that can be very individual) and  which sources.

Not recommended, but pretty cute:

Overall; fiber promotes colonic health by providing a source of Short Chain Fatty Acids; helps maintain healthy populations of friendly bacteria and regulates not only the rate at which stool passes through the system but also  blood glucose levels as well.

As with all foods – there are pros and cons to fiber, the amount and type  you use in a home made diet must work with A) what we know about dogs in general, scientifically – and B) your individual!  For dogs on diets very high in carb overall, including fiber, I adjust the minerals to address possible absorption problems – although all nutrients may need to be raised above RA to avoid running low. Usually, however, this is not necessary. You might think of increasing fiber if your dog is constipated, has anal gland issues, has kidney or liver disease, or has sloppy stool without a precise veterinary diagnosis (fat reduction is another thing to try in this case). What type helps will depend on your dog, but psyllium is a time-honoured helper for those needing soluble fiber, and brown rice or cooked pumpkin/sweet potato offers relief with insoluble fiber (and a host of other nutrients). Don’t overdo it, and be aware that soluble fiber in particular can block absorption of some nutrients and medications. When I give psyllium, I often add it to a fatfree home made meat stock, and give it as a treat – in between meals, and well away from medications.

All dogs are not the same! Find what works for yours.

Upcoming entries will cover: a summary of carbs, and what a recipe with 25-30% carb looks like; explorations of individual foods, pro and con, and preparation tips; the real scoop on fruits and vegetables in the diet; how much carb is in your grainfree food?  popular myths about carbohydrate – and yep, eventually we will get to protein. I promise.

Oh – and more Ridgebacks. I can pretty much guarantee that one.


Canine and Feline Nutrition: A resource for Companion Animal Professionals (Case, Carey, Hirawaka, Daristotle)

NRC Nutrient Requirements of Dogs, 2006

Countless years of casework 🙂