Carbohydrates in Cat Food – Refining a Complex Issue
Dr Justin Shmalberg
Carbohydrates in Cat Food – Refining a Complex Issue
Perhaps no greater controversy exists in feline nutrition than that of carbohydrates in cat food. Understandably, cat parents frequently question what science, evolution, and unique feline physiology tell us about the subject. With this article we hope to help by giving some technical understanding to a subject that is often guided by emotion when making dietary decisions for our cats.
Firstly, let’s start with the fact that cats are obligate carnivores, as this is not up for debate. Cats share features of all true carnivores physiologically, such as:
- The need for preformed vitamin A (versus being able to use beta carotene as a precursor);
- Higher protein requirements;
- Their internal processing is geared for making blood sugar from amino acids rather than dietary sugars;
- A shorter digestive tract;
- An explicit need for preformed taurine (made from other amino acids in dogs), among others.
We all accept that wild cats are hunters when it comes to feeding habits, although they admittedly seem to hunt for sport as well. These facts all provide a pretty compelling case to argue that carbohydrates for cats have no benefit and can’t be absorbed. Well, that’s where it gets a little tricky.
Cats, in spite of not seeking out carbohydrate rich foods (although I’ve seen the odd house cat go after carbs from the counter), can efficiently digest and absorb simple carbohydrates, although not quite as well as their omnivore or herbivore friends. Kibble contains such carbs, and it’s certainly been shown that these are absorbed (they aren’t just ‘fillers’ passing through the gut into the stool). The portion of complex carbohydrates which aren’t absorbed, as well as soluble fibre, do also play some role in feeding the gut bacteria in cats (and cats appear to have a unique fermentation process for these in their colon compared to other species). In addition, these substances are found in the natural prey they eat, at about 10% of total calories or slightly less. So, from an evolutionary perspective, cats were not eating a completely carbohydrate free diet.
The question remains, do cats need carbohydrates? Well no, just as arguably dogs don’t and people don’t either; they and we can derive essential nutrients from diets free of plant material (just so happens here that Atkins and KatKin rhyme - totally unintentional). Before we talk about the KatKin approach, let’s talk about what we know about any dangers from carbohydrates.
Unfortunately, this is not as clear cut as one would hope. Despite all the interest in carbs and cats from the public, there just aren’t lifetime feeding studies comparing cats that consumed high carb, low carb, or no carb diets. I wish there were. If we know cats absorb carbs to some degree, it’s obvious to ask the question of what effect they have. Well, they do contribute to blood sugar (glucose), and glucose in the blood is necessary for a cat to survive. If they don’t have carbs, they will build it just fine from certain amino acids. What about excess sugar? Surely that causes diabetes? Well, it doesn’t seem so. The main cause of diabetes in cats is obesity (which is different in dogs for those keeping inter-species score). Certainly, energy-rich foods like kibble are more apt to be overfed without care from a cat parent, but the link between carbs and obesity isn’t well-established in cats if one exists. At the end of the day, there are a lot of theorized disadvantages to carbohydrates, but we just don’t have many studies that have examined the question. Which is as frustrating for me as I’m sure it is for you. Now, before you think I’m advocating for a diet with 50% carbohydrate calories, I’d implore you to read on.
It’s only fair to talk about possible advantages to plant-based material in low amounts (let’s say for the sake of argument, similar to that of a natural prey item). We know it may be absorbed and contribute to energy, and while your cat may be the type to seem like he’s not using any energy perched on the bedazzled custom window sill resting area you built for him, even he needs calories. More interestingly to me, however, are phytonutrients - these are generally nonessential nutrients your cat could live without, but which may confer some health benefits. Take beta-carotene for instance (think carrots here): this vitamin A precursor doesn’t work in the cat (unlike dog and human) for vitamin A as we learned, but it is absorbed and does have impact on immune cells and can serve as an antioxidant in cats (aka free radical fighter to combat cell damage). Your cat will be fine without it, but could actually get some benefits from its inclusion in the diet. There are a number of other compounds that have a similar story, and while you could certainly just add purified beta-carotene to a diet, that wouldn’t really be a whole foods approach to the problem. Admittedly, some of the ingredients that contain such phytonutrients might not always be in the prey of cats, but the principal phytonutrients may well be there from another source.
So, what to do? You certainly have some options, you could feed a higher carbohydrate food than in natural prey items (often necessary if feeding kibble because carbs give the kibble form and shape); or feed a diet approximating that of natural prey (let’s call this a touch of carbs); or just leave all the carbs out. Well your cat will be certainly fine with the latter and may even thrive, but could miss out on some of those prebiotic fuels for gut bacteria and some potentially interesting phytonutrients. Since we built all of the KatKin diets ourselves, from the ground up, we went with the middle option of a diet closer in carbs to natural prey, our ‘touch of carbs’ approach.
The KatKin diets all have less than 5% of calories as carbs (actually less than in natural prey) with some variation from recipe to recipe. Plant-based ingredients are less than 5% by weight (ingredients may contain both carbs and fibre). The reasons for the inclusion are as above, and the good news is that if your cat doesn’t take to the carbs, the diet is still complete and balanced and your little one won’t be missing out on calories and start losing weight if they leave them in the bowl (since it’s such a small part of the recipe). If you wanted to pick them out and were finding yourself with a lot of extra time on your hands in lockdown, we suppose you could, but we’re confident they won’t cause any harm and may well do a bit of good! We do, however, value your feedback and our first goal was to educate on how we approached carbs and the formulas broadly. We have no doubt that as the KatKin community grows (and thank you, by the way) there will be an expansion of the recipes on offer.
Before we go, it’s a great time to mention some other unique features of KatKin. The first is you can certainly find a meat your cat will enjoy with all the flavour options. This can be particularly helpful for those cats that need a new protein source (due to food allergies for instance) or those who are just choosy about what they’ll eat (we get it, it’s a cat thing, trust us). The diets are all naturally high in moisture which helps to maintain hydration and can be particularly helpful for certain conditions, but which we feel benefits all cats (don’t be alarmed if your indoor cat’s water intake goes way down after a transition - that’s typical of cats to get their water in food).
Also, we formulate for all life stages - providing additive nutrient boosts for cats of all ages. The high protein level is helpful not only for matching the evolutionary machinery of cats, as described above, but also to maintain their muscle mass (or help them to lose weight if they’re a little chubby). And let’s not forget custom portioning to prevent overfeeding (all too easy to do in cats). Basically, it’s all the stuff we think best for cats, delivered to your door. Hopefully, you now have not only a better understanding of carbohydrates in cat food, but also of the KatKin approach. Thanks for joining us on the journey!
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