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The diet you choose to feed your cat is critical in maintaining their health and the last thing any pet parent wants is to give them a diet that is harmful.
But, there is a lot of confusion (and misinformation) about what to feed a cat, what is healthy and what is harmful with some of the most common diet choices said to cause obesity, cancer, kidney failure and more.
This conversation with an expert veterinary nutritionist, Dr. Dottie LaFlamme, will help answer the most common cat-feeding and cat food questions:
Are carbohydrates bad for cats
Does dry kibble cause kidney failure
How many meals should you feed your cat
And so much more!
There is no evidence of adverse effects from carbohydrates in the diet, so long as the diet provides all of the essential nutrients that cats need
Evidence-based Nutrition
Dr. Alex Avery:
Today we're really going to dive into the world of cat nutrition, what to feed a cat, and some of the myths, or the many myths that are out there.
And with my tongue firmly in my cheek, I'd love to start with the myth that vets don't learn about nutrition…
So how on earth can we know that you know what you're talking about? Which is my very impolite way of saying, you know, what's your background and what brought you into the world of nutrition?!
Dr. Dottie LaFlamme:
You raise a good point because some veterinarians don't get trained in nutrition and others get great coverage in their veterinary curriculum.
Personally, I not only have my veterinary degree, but I also have a master's degree in ruminant nutrition and a PhD in clinical nutrition where I focused on dogs. And then I did a post-doctoral residency in clinical nutrition.
And then I went to work in research and development where I focused on canine and feline nutrition for over 25 years. So somewhere along the line I think I picked up a little bit.
Dr. Alex Avery:
I think that's very modest, and you’ll have more knowledge than most!
What to Feed a Cat
The first statement that I'd love to explore with you about what to feed a cat is the fact that cats aren't able to utilize carbs, or carbohydrates, in their diet. And even worse, carbs are harmful to the health of a cat.
Feeding Carbs to Cats: Is It Harmful?
It's something that I commonly hear pet parents talk about or read comments about. So I'd love your input on those two statements and dive deeper into that.
And I guess where this belief comes from is the knowledge or the statement that cats are obligate carnivores.
So what does that mean and what is the role of carbs and can cats actually utilize them?
Dr. Dottie LaFlamme:
Well, I hope we have several hours because it'll probably take that to really dig into each of those. Sure, you're right. I mean, those are probably among the biggest misperceptions about feline nutrition.
Cats Are Obligate Carnivores
Why don't we take it from the top and talk about what it means to be a carnivore and what it means to be an obligate carnivore just as a starting point as this will help better understand what to feed a cat if we want them to be as healthy as possible.
So carnivore is a taxonomic categorization. Dogs are carnivores, cats are carnivores, bears are carnivores, so forth. And yet there are vegetarian bears. So let's just recognize that the fact that something's called a carnivore in itself doesn't mean anything.
The perception is that cats are obligate carnivores. What that really means is that cats require certain nutrients that are found in nature only in animal products
For a carnivore, basically what that means is that that animal naturally will be a prey eater. Let me elaborate a little bit even more on that. When we talk about a dog or a cat or any other carnivore that's eating in the wild, they're eating prey. That means that they're an animal eater, which is different from a meat eater.
Some people think I want to feed my animal like a carnivore, so I'm going to give them steak, I'm going to give them chicken breast, and whatnot.
Sure, That's wonderful protein. But it's not complete nutrition.
When a cat eats a whole animal, when a dog eats a whole animal, they're eating the muscle, but they're also eating the organs. They're also eating the contents of the intestines. So they're getting a much broader collection of nutrients than just eating meat.
So carnivore means animal eater and cats are called obligate carnivores because they require certain nutrients that are naturally found only in animal products.
What it does not mean, it does not mean that carnivores or cats cannot utilize other nutrients.
What it means is this is a handful of nutrients that they have to have, either naturally from animal products or synthetic sources. For example, some vitamins and minerals can be provided synthetically.
Dr. Alex Avery:
And that's a really important definition because when you hear that phrase obligate carnivore it can seem like the logical jump to then say they need to eat meat and only meat. But that's not what it means.
They need to have a proportion of the proteins that are naturally present in meat in their diet. But they can absolutely utilize all of these other things that they're eating.
Dr. Dottie LaFlamme:
Absolutely. And it's certainly not just the proteins from animal sources. It's vitamins and minerals as well. So there are lots of different nutrients to consider.
Most of the time the easy thing, of course, is to just think about what nutritionists call macronutrients: proteins, fats, carbohydrates. They're called macro because they make up the biggest part of the diet, and make up 100% of the calories that the animals consume.
But of course, a complete diet, a balanced diet has those plus vitamins and minerals as needed by the animal. Today, I don't think we're going to be talking about those other nutrients. We're going to just assume that we're talking about a balanced diet and then focus on the macronutrients when deciding what to feed a cat.
A Cat’s “Natural” Diet
Dr. Alex Avery:
The problem with the topic of nutrition and trying to answer what to feed a cat is that we could probably talk for a week and still only scratch the surface!
With all this in mind, we've got our cats, their hunting their prey, small rodents, whatever it is. What nutrient profile do they provide the cat. You've spoken about the organs and their stomach contents. So they're going to be eating a certain percentage of carbohydrate in their natural diet as well.
Dr. Dottie LaFlamme:
There have been a couple of studies looking at the typical diets of feral cats.
And what that translates to in terms of those macronutrients is that protein is the biggest component. Fat is the next and carbohydrates are the smallest amount, with somewhere between 2-6% of the cat’s calories coming from carbohydrates. The biggest chunk of it comes from protein, with fat also making up a big component.
The difference between that particular breakdown of, let's call it 5% carbohydrate then can be compared to commercial dry diets that might have 30 to 45% carbohydrates.
That difference in carbohydrate content is part of perhaps part of the misperception or the concern about foods and why are cats getting so much carbohydrate.
We're going to be talking about that. But I want to bring up another point. We've talked about the term obligate carnivore. We also need to bring up another term, and that's called opportunistic diet.
Some people think about this evolutionary diet, whether they're talking humans or they're talking about wild dogs and wild cats based on what those cats in the wild could eat.
I want to bring up the term opportunistic diet, because that indeed is what wild animals eat. They eat what they're able to hunt or they're able to catch.
And if they are successful in harvesting enough prey, or if they don't have prey they eat enough roots and leaves and plants and whatever they might eat to fill their bellies, if they're able to consume enough nutrients then they survive. And then that species, that individual will survive.
It doesn't necessarily mean it's a perfect diet. It doesn't mean it's the best diet. It's what the opportunity provides.
If we think about feral cats today. Yes, they live on a diet that's low in carbohydrate, high in protein. But they also don't live very long. The average lifespan of a feral cat is somewhere in the 3 to 5 year range. Not that they die from malnutrition necessarily. Mostly they die from traumatic issues. They're killed by other animals. They become prey themselves or are killed by cars.
But the point is that they don't live 15 or 20 years like we want our pet cats to do.
Dr. Alex Avery:
And that's a hugely important statement to make. Because they are living long enough to breed, and cats breed very successfully and very quickly and at a young age, any nutritional problems that may manifest later on don't make a difference to that overall cat population.
That's what I'm hearing you say.
Dr. Dottie LaFlamme:
That's exactly what I'm saying. Thank you.
Do Carbohydrates Cause Disease In Healthy Cats?
Dr. Alex Avery:
That leads us nicely to the statement that carbohydrates aren't just not able to be utilized by cats, but they're actually harmful and are responsible for a lot of the chronic diseases that we're seeing. The cancers, the endocrine problems.
And because of that, we shouldn't be feeding cats that are otherwise healthy, these carbohydrates so that they don't get these problems later on in life.
Is there any truth in any of that?
Dr. Dottie LaFlamme:
Let's start with the short answer: No!
But then let's go to a better context. And let's start by talking about what exactly are carbohydrates and why are they in foods.
The Role Of Dietary Carbohydrates
So carbohydrates are a broad category that includes sugars. From a biochemical point of view, it's carbon, hydrogen, and oxygen put together at a particular ratio.
This forms simple sugars, like table sugar. Blood glucose is a sugar, it is a carbohydrate
Or they can be much more complex sugars, larger molecules. And we think about starches and we think about complex carbohydrates which are found in whole grains and so forth. These we know from the human perspective are very important and very healthy.
And then there's a whole other category, and that's the indigestible carbohydrates, which is fiber.
And by definition, they're not digestible but they're also important because they do provide for GI health. They provide foodstuffs for the microflora that live in the gut, which is an important component, whether you're a cat or a person or a dog. This GI microflora is important to our health.
And so some amount of dietary fiber is important to keep them healthy.
That said, we're going to focus just on the digestible carbohydrates, but still, we're talking about a big difference between complex carbohydrates, such as those found in grains, and simple sugars, which might be found in table sugar or sodas and things like that.
And there's a difference in how these two carbohydrate types are processed and metabolized in the body.
One of the things I want to point out is that if you look at the literature, there are lots of articles that talk about how carbohydrates are bad. Most of this work is coming from the human side, whether it's actually people in the study or mouse models or rat models. They're talking about high carbohydrates being bad.
But if you look at them, what you find is that those studies were looking at high-sugar diets. And if you look a little deeper, what you find is that high carbohydrates, when it's complex carbohydrates such as whole grains, instead of an adverse effect, you find beneficial health effects.
So on the human side, it depends on what carbohydrates we're talking about.
Dr. Alex Avery:
But we're not tending to give our cats carbonated beverages or candy. So generally, I guess, we're talking about complex carbohydrates. Would that be fair?
Dr. Dottie LaFlamme:
Well, I think if we're talking about what's present in diets, it's predominantly complex carbohydrates.
But a lot of the misperception that carbohydrates are bad is an extrapolation of the sugar. And there have been studies done with cats over several decades, I guess a few studies here and there.
And one of those studies used sugars, high levels of sugar in the diet and did indeed find some adverse effects. When very high levels of sugar was present in the diet, that caused some damage to the kidney and it caused some damage to the GI tract.
But when the same amount of carbohydrate in the form of complex carbohydrates was provided, there were no adverse effects. None of those same things were seen.
We have to take into consideration that the effect on the cat may very well depend on what source of carbohydrate.
Do Cats Need Carbohydrate In Their Diet?
Nevertheless, let's come down to how much carbohydrates cats need.
Here, we have to differentiate between what we call a dietary requirement and a physiologic requirement. And what I mean by that is dietary requirement means that the animal or the person has to have that nutrient as a component of the diet or they're not going to survive. That's a dietary essential nutrient.
For cats, for dogs, for people, there is no requirement for carbohydrate to be a part of the diet.
That said, there is a physiologic requirement, which means that the cat's body, the human body, has to have carbohydrate in the form of glucose in the bloodstream. Blood glucose is the primary energy source for almost every cell in the body.
And if we don't have enough glucose in the bloodstream, basically, we're going to die. We don't want too much, of course, that's associated with diabetes. We don't want too little because then you have hypoglycemia, you have coma, you die. We don't want either of those. We want the right amount in the bloodstream.
And because of that, our cat's body, our own body, has all kinds of homeostatic mechanisms. In other words, the body has ways that the body maintains blood glucose at the right level for normal health.
Now, getting that back to the diet, when I said we don't have to have it in the diet but we have to have it in the blood, how does it get into the blood?
There are two options. One is it can come from the diet, so carbohydrates in the diet can be digested and metabolized to provide the glucose that's needed by cats. Or they can take dietary protein and break it down. There's then a process called gluconeogenesis (gluco- means glucose, -neo- meaning new, -genesis means being made).
In other words, the body can make new glucose from protein or it can come from carbohydrate in the diet. But because there's that backup capacity to convert protein into glucose, it doesn't have to have it from the diet. And so it's not an essential nutrient.
Carbohydrate is still a wonderful source to provide the glucose that the cats actually do need.
And yes, cats are able to digest carbohydrates, process carbohydrates, and use carbohydrates from the diet in a manner similar to other species.
Dr. Alex Avery:
Something else that I don't want to dive deep into now, but people who have listened to the show before will know that I've spoken several times about the environmental cost of pet food and how this needs to be considered when deciding what to feed a cat.
And if we're relying on the protein component, we know that it's more expensive to produce, it has a higher environmental cost. And so relying on proteins has that impact as well.
What Cats Should Avoid Carbohydrates?
When it comes to diabetes, this is a good time to ask if there are any health conditions where actually it's better not to feed a lot of carbohydrates to cats?
No Carbs vs Too Much
Dr. Dottie LaFlamme:
There is a review article that some of us did where we looked at all of the literature, all of the data that's out there relative to the impact of carbohydrates on cats. And what we found in that very extensive review is that there is no evidence of adverse effects from carbohydrates in the diet, so long as the diet provides all of the essential nutrients that cats need.
And I qualify it in that way, because if you fed your cat a really, really high carbohydrate diet, then you're probably not going to be providing enough protein, enough fat, and enough other nutrients. And that can contribute to an issue.
So our group that did that review basically found that, of the data available, carbohydrate can provide up to as much as 50% of the calories in the diet without causing any adverse effects. Again, so long as there's enough protein in the diet.
Fat doesn't have to be particularly high, but the lower the carbohydrate, the higher the fat will be because the diet has got to add up to 100%. And if you take one piece of it away, the other two pieces have to make up the difference. And so usually a low carbohydrate diet is higher in fat as well as higher in protein.
So in terms of adverse effects from high carbohydrate, really in a healthy cat, it's only if it's so high that it contributes to loss of the other essential nutrients.
And then with healthy cats, the opposite also has to be considered. Are there adverse effects of low carbohydrate diets?
As I was just mentioning, when you take away one nutrient, the other macronutrients make up the difference. This means that most low-carbohydrate diets are actually high in fat. Fat is much higher in calories than carbohydrates. And so high-fat diets actually are a risk factor for obesity. And obesity is a risk factor for a number of health problems in cats as well as other species.
Dr. Alex Avery:
It's a huge issue that is increasing in prevalence across the cat, the dog, and the human population.
Diabetic Cats
I'm also thinking here about diabetic cats and the high protein, low carb diets being thought of as the best option. Is that the truth? And are there any other conditions, that cats already may have, where we need to be a little bit more cautious with the carbohydrate content of their diet?
Dr. Dottie LaFlamme:
With the perception that low carbohydrate and high protein diets are beneficial in cats with diabetes, the scientific evidence to support that is not as strong as we'd like it to be.
But there is some evidence that they are beneficial, and clinical experience amongst a large number of experts in the field support that there is a benefit in cats that are already diabetic.
This is because these cats have lost their natural ability to regulate blood glucose. One of the challenges with diabetes is the blood glucose gets too high because it's not being taken up into the bloodstream fast enough and so it's not being metabolized fast enough.
So there are two ways we can try to prevent that excess carbohydrate in the bloodstream. One is to put less carbohydrate in the diet, and the other is to feed small amounts of food over an extended period of time, which is the way that cats would naturally eat in the wild. Small meals, multiple meals a day which prevents a massive influx of blood glucose all at one time.
Those are two things that we can do. In addition, of course, to providing them with insulin or other medication as needed.
Dr. Alex Avery:
Diabetic cats can be quite challenging to stabilize in some cases.
Equally, I have a patient at the moment who is, I believe, 21 or 22 and has been diabetic for five years and is still going strong. That may be defying all expectations but with good management it's certainly possible.
Does Dry Kibble Cause Kidney Failure in Cats?
I'd love to switch now to our next statement, which is that dry diets are unhealthy because cats have a low drive to drink. They don't drink a lot naturally, and cats also commonly suffer from kidney failure…
…Therefore, dry diets are causing kidney failure and a host of other problems…
Is there any evidence behind these allegations to better help us decide what to feed a cat? Is wet food healthier for cats?
Dr. Dottie LaFlamme:
That does not seem to be true.
As a matter of fact, there's evidence to the contrary.
I think part of the perception that dry foods were going to be causing problems is that, yes, water is a piece of it, but the high carbohydrate content was also a piece of it. Now, we've talked about carbohydrate in sufficient detail, but that combination has led to the perception that dry foods are in some way damaging for cats.
The reality is the vast majority of cats have no problem maintaining hydration.
There are exceptions. It may be a cat that's very senior. It may be a cat that already has kidney disease. It may be a cat that has urinary stone disease. There are certain cats that really will benefit from having extra water to their diet. And those cats might do better on a high-moisture diet rather than a dry diet.
But the vast majority of cats should do just fine on dry food.
I was actually looking for any scientific evidence that would support the perception that dry foods contribute to kidney disease. And actually what I found was a fairly recent study that said just the opposite. Cats on dry food are less likely to develop kidney disease than those fed wet foods.
But if you look at the literature in its entirety, you will find some studies that suggest that dry foods are associated with certain conditions. You might find an association with urethral obstruction, urinary tract obstruction, or urinary tract disease. You might find evidence that dry foods are linked with diabetes. You might find them linked with other conditions.
But then there are other studies that show just the opposite. That there's a protective effect of dry food against kidney disease. There's a protective effect of dry food against thyroid disease.
Certainly, dry food seems to be better in terms of dental condition.
With this in mind, I don't think that we can draw a line in the sand in any way and say dry food is bad for the vast majority of cats.
And so for our cat owners out there, I think if you like feeding dry food and your cat enjoys eating dry food, there's really no reason to switch them onto a wet food so long as they are healthy and unless a veterinarian diagnoses another problem.
Dr. Alex Avery:
Just because cats who have existing problems benefit from, or may benefit from, a higher water content diet doesn't mean that all cats need that diet.
Is Wet Food Healthier for cats?
From the point of view of what to feed a cat, that's an interesting one.
I feed my cats dry kibble the majority of the time. But I do also feed them different types of wet food.
Because one thing I worry about is cats becoming fixated on a particular diet, the “kibble junky” is a classic example, and then we want to switch them to this higher moisture content food, should anything happen, we can really struggle to get them to eat it.
Dr. Dottie LaFlamme:
This cat-feeding strategy makes perfect sense, and from what we know about cats is a good strategy.
Even if it's just as an occasional treat, it doesn't necessarily have to be every day. As well, it's a good way to provide a flavor variety for your cat instead of constantly changing the primary diet. You can be feeding them a nutritionally balanced dry food, for example, and then the canned food that you put on top of that or beside that could be a number of different flavors across different days.
You don't want cats to become fixated on a particular food. And while we're probably not really talking about kittens here, it seems that the key time for introducing cats to different foodstuffs is when they're young. If you do have a kitten, feeding a variety of different foods while they're young is a great idea for exactly that purpose. They learn that all these different textures and flavors are food too.
Dr. Alex Avery:
And this is something that people really struggle with: “My cat is fussy and won't eat that diet” is something that I hear all the time.
But we can train them, or even “socialize them” to their food.
My cats know what goes in their bowl is what they need to eat or else they're going to go hungry. And as a result, they quite happily accept new diets straight away the first time I feed them.
They've not trained me to just feed them one particular thing. Which happens because our pet cats are very smart!
Dr. Dottie LaFlamme:
Thank you for putting it that way, because our cats are quite good at teaching us how to care for them and how to spoil them.
Dr. Alex Avery:
And we're suckers for it because they're part of the family and we want them to be as happy as they can be.
How Many Meals Should a Cat Have Each Day?
The last thing I want to talk about today in our discussion about what to feed a cat is actually how cats like to eat.
We talked earlier about how they naturally eat smaller, more frequent meals. And the act of searching for their food and hunting and killing can also be important.
I've also heard that from a feeling full point of view, and we spoke about the problem of obesity as well, that actually feeding one big meal is the best thing that we can do to help them stop feeling hungry.
How do you recommend people go about feeding their cat? Is it with ad-lib feeding, having food down all the time so that they can choose to have these small meals?
How can we feed our cats to best optimize their physical and mental health?
Dr. Dottie LaFlamme:
That’s a great question but, unfortunately, the simple answer doesn't exist.
Every cat is an individual. Every home environment is unique. And so what works in one household may not work in another household.
There are however some pros and cons of different approaches.
Managing Meal Time
One thing that we both know is that very few cats are in a single-cat household. There are some, but most cats have at least one or two feline siblings. And so we have to think about how we are going to feed all of the cats.
If you’re meal feeding, it's not so difficult to set down one bowl per cat. Give the cats half an hour, perhaps in different rooms if need be to prevent stealing, give them time to eat and then take up whatever's left, if anything. And that's it.
And then they're done until the next meal time. You should feed them at least twice a day. Cats can survive on once-a-day feeding, but most of us would prefer to feed 2 meals a day.
Cats might prefer ten times a day, but you can get by with feeding once or twice a day. But even that separation, I think, doesn't work in many households.
Ad-lib feeding
What a lot of people tend to do is put dry food down that all the cats have access to. then, in addition, they will feed wet food. And sometimes the wet food can be separated among the different cats. But it's very typical for cats to get a combination of dry food and wet food.
Is it necessary? No. But as we were just discussing, there are certain advantages to it.
As far as feeding frequency. Again, cats in the wild and feral cats will tend to eat many, many different meals a day. And part of that is because they have to hunt for their food. They'll catch a mouse or a bird or a lizard and they'll eat it and then they'll catch another and then they'll eat it and so forth and so on.
But even in a research setting, given the opportunity, most cats will generally be nibblers and they will eat up to 20 times a day if they have the opportunity.
One important point here though is that this is usually measured in individual cats who don't have other cats competing for that same food. And so that creates a different scenario because if cats are going to be eating each other's food, then you have to think about what's the best way to do that.
Top Cat Feeding Tips
So bottom line, I can't give you what's the perfect way to do it, because every home is a different situation. There are a few tips that I can provide.
Feeding Fat and Thin Cats
In households where there are cats of different body condition scores, you have your lean cat and you have your fat cat, what can work well is to use a creep feeder. This is basically a box that has a small hole cut into it that only the skinny cats can get in.
The thin cat’s food is placed in this feeding box and they are allowed to come and go as they please. But the fat cat can't get into the box and so can’t access this food!
They can then be fed controlled amounts as many times a day as the owners choose to do so.
Weigh Your Cat’s Food
Another ideal with the obese cat is to measure out their food once a day. And if you have multiple cats, measure it out once a day on the kitchen scale - 50 grams for this cat, 70 grams for this cat - put it in their little baggie, feed it to them as many times a day as you wish.
But when the bag is empty, the bag is empty, and they get nothing more.
Use Active Feeding Toys
Active feeding is probably the direction that most feline nutritionists are encouraging. If we can encourage cats to work for their food, it replaces their ability to hunt for food.
Food toys, whether it's a ball or whether it's one of these various mazes, putting the food into a feeding toy is a great way to do this because it encourages activity. It's mental stimulation. They burn a few calories. It slows down their eating.
There are lots of benefits to active feeding and so that's another thing that I would certainly recommend.
Dr. Alex Avery:
And these feeding toys don't have to be the expensive ones on Amazon. They can be homemade. Even something as simple as using a toilet roll inner cardboard tube with a few holes punched in it which the cat has to bat it around and the kibble falls out.
Dr. Dottie LaFlamme:
Or a water bottle with holes punched in it that the kibbles can fall out of. It can be as simple as that!
Cat Feeding Resources
Bio: Dr. Dottie LaFlamme
Dr. Dottie Laflamme received her MS in ruminant nutrition, Doctor of Veterinary Medicine degree, and PhD in nutrition and physiology, all from the University of Georgia. She completed her clinical nutrition residency as an ALPO Postdoctoral Fellow in Clinical Nutrition. Dr. Laflamme is a Diplomate and past-President of the American College of Veterinary Nutrition.
She is an author on over 250 scientific and technical publications; and has been a speaker at a number of veterinary, research, and continuing education programs worldwide. She worked for Purina (first Ralston Purina, now Nestle Purina) in the Research and Development Department from 1990 until her retirement in 2015.
Her research focused on therapeutic nutrition, especially obesity management, and geriatric nutrition. She currently works as an independent consultant. Dottie lives in the Blue Ridge Mountains of western Virginia.
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