cat food ingredients

Is Dry Food Bad for Cats?

Dry cat food (kibble) is perhaps just as common as wet cat food. But is it suitable for cats? Is it good for a cat’s health, or could it have long-term effects? Should you feed it or not?

Is dry food bad for cats? It is. It doesn’t reflect a cat’s wild diet, is nutritionally unsuitable in more than one way, and can cause long term health issues like kidney disease and obesity. That applies despite it remaining popular and being frequently advertised. Instead, feed your cat wet cat food or raw cat food as these are more suitable choices. Pick a food with a minimum of grains and other bulking additives, which instead has as much meat in it as possible.

The guide below addresses how dry cat food is bad for cats, and a few dry vs. wet cat food pros and cons.

Is Dry Cat Food Bad for Cats?

Dry cat food is bad for cats in several ways.

  1. It isn’t natural. ‘Natural’ doesn’t always mean ‘good’, but as a general rule, cats need to eat diets that match their wild diets and display behaviors that mirror their wild behaviors. This is one case in which the natural choice (real meat) is the better one.
  2. It isn’t nutritionally suitable. Kibble can contain the wrong kinds of protein (incomplete vs. complete proteins). It also doesn’t contain enough water for a cat, and cats don’t drink enough to make up for that fact.
  3. Dry cat food causes long term health issues. Kidney stones, UTIs, tooth decay and obesity can all result from a dry-food diet.

The simple answer for why dry food remains popular, despite being inadequate, is that we’re still learning how to take care of our pets as best we can. Advances in medical science over the past decades/century have revolutionized how small pets are cared for, for example. In the same way nutritional analysis of food, and a biological understanding of how food supports the body, are both fields of science that continue to evolve. There’s also a vested interest on behalf of manufacturers to encourage people to continue buying their products.

Can Cats Live on Dry Food Only?

dry cat food
Cats can enjoy eating dry cat food, and can live long, mostly healthy lives eating the stuff. But that doesn’t mean it’s best.

Cats can live their whole lives eating nothing but dry food. It contains enough energy for them to survive (and even gain weight), and won’t cause any immediate health concerns. That’s why dry food has become so popular over the years. In that sense, dry cat food is a lot like the snacks that we eat.

Admittedly, there are a few reasons why dry food is good for cats (or at least good for your wallet). It’s cheap and easy to find/buy. It lasts for a lot longer than wet cat food when put out for your pet. You can also free feed with it, which can be a good thing.

But that doesn’t erase what’s bad about dry cat food. A person could survive for a long time eating nothing but candy and chips. But that doesn’t mean you should, and nor should your cat live on dry food.

1) Is Dry Cat Food Natural?

As a pet owner, it’s your job to give your cat the healthiest and happiest life you can. While not all things that are natural are good, or are best for your cat, whether something reflects your cat’s wild experience can be a good yardstick as to whether it’s right or not.

In this case, dry cat food is not natural. It’s made with ingredients that your cat won’t eat in the wild like grains, vegetables and cooked meat. As we’ll see in a moment, this makes kitty kibble nutritionally unsuitable for cats. At the same time wet food, and especially wet foods that contain raw meat, are both more akin to the cat’s wild diet and better for it.

Wet cat food is more similar to a cat’s wild diet, albeit not the exact same. Raw meat diets that are carefully selected to be nutritionally appropriate are the best.

2) Is Dry Food Nutritionally Suitable for Cats?

In some ways, manufacturers seek to make dry food as nutritionally suitable for cats as possible, for obvious reasons. But in other ways, kibble remains distinct and different to a cat’s wild diet, which can lead to disease in later life.

Carbohydrates, Protein & Fat

To fully understand whether or not dry cat food is safe for cats, we should look at some examples, like this one from Purina. There are two ways to think of kibble’s content: either by breaking it down in a nutritional analysis, or reading through the ingredients list. Both are presented below.

Typical ValuesAnalytical Constituents:
Fat content:11%
Crude ash:8%
Crude fibres:3%
Linoleic acid:1.8%
Arachidonic acid:0.1%
Nutritional Additives:IU/kg:
Vit A:12 500
Vit D3:1 000
Ferrous sulphate monohydrate:145
Calcium iodate anhydrous:2.4
Cupric sulphate pentahydrate:35
Manganous sulphate monohydrate:15
Zinc sulphate monohydrate:182
Sodium selenite:0.23
Colourants1 and antioxidants
1no added artificial colourants

This dry food contains 30% protein and 11% fat, which is roughly adequate for a cat. The additives mean that the food supplies everything that a cat needs, like taurine. However, in terms of ingredients, the list is less suitable:

Cereals, Meat and Animal Derivatives (10%*), Vegetable Protein Extracts, Oils and Fats, Derivatives of Vegetable Origin, Minerals, Yeasts, *Equivalent to 20% Rehydrated Meat and Animal Derivatives, with min. 4% Chicken and min. 4% Duck

The problem here is that vegetable proteins aren’t necessarily the same as animal proteins. Animals proteins are complete proteins, while most vegetable proteins are incomplete. The difference is that proteins are made up of amino acids, which stack up like building blocks to form protein strands. Complete proteins contain every amino acid, while incomplete ones only contain some. As it’s unclear where the proteins in dry cat food come from without directly messaging the company about their manufacturing processes, it’s therefore also unclear whether these proteins are complete or not. Since cats eat meat, they’re used to complete proteins, so these are best for your pet.

Another problem is if the kibble contains lots of carbohydrates. It’s not listed in the nutritional analysis, but this one does. Cats don’t need a lot of carbohydrates, because they’ve evolved to best digest proteins and fats. Your cat’s intestines are shaped so as to be far better at digesting meat and getting the energy from that rather than from grains and other sources of carbs. It’s therefore best to limit the carbs your cat eats.

Moisture Content

homemade cat food
Meaty cat food clearly has a higher moisture content than dry food. In this way, it’s much more suitable.

The worst thing about dry cat food, though, is that it contains next to no moisture. This is what gives kibble its dry and rough texture.

The problem is that cats like food that has a relatively high moisture content. Meat contains around 65-75% moisture in total, and it’s from that moisture content that cats get most of their water. That’s why cats drink so little.

When cats eat kibble, they miss out on this water content, but don’t drink enough to make up for it. This dehydration is the root cause of the health issues that kibble causes later in life.

3) Does Dry Cat Food Make Cats Sick?

Kibble won’t make your cat sick, as in make it vomit. But dry food will cause health problems in the long run.

Does Dry Food Make Cats Fat?

One issue that owners frequently encounter is that dry food makes their cat obese.

The problem is that you can free-feed dry food. That means leaving food available at all times for your cat. You can’t do that with wet food, which goes bad quickly and attracts flies, but with dry food it’s fine.

Free feeding doesn’t necessarily lead to overeating, but it can. Since cats are used to meat, they know how much to eat to maintain their weight, and cases of obesity are rare in cats fed wet food or raw meat. They aren’t used to kibble in the same way and consequently stand a higher chance of overeating it.

Being slightly overweight isn’t too bad for a cat. It’s when the cat becomes grossly overweight that complications like diabetes can occur.

Lower Kidney Function

The low water content in kibble can kidney problems in your cat. There are several forms that these kidney problems can take, and one issue can follow the other, severely affecting your cat’s health.

The issues begin with lower kidney function. Dehydration causes a buildup of acids, waste products and myoglobin in the body. These are excreted through the kidneys and can damage them when they aren’t diluted with water. This damage doesn’t occur overnight, but gets worse and worse over time, and leads to lower kidney function. That’s where the kidneys don’t do their job as well as they should.

Kidney Stones and Bladder Crystals

Another side effect of dehydration is the formation of crystals in the kidneys and bladder. These crystals form when urea remains in the kidneys or bladder for a long time without much water to dilute it down. These tiny jagged crystals grow bigger and bigger until they form a stone, i.e. a kidney or bladder stone.

A kidney or bladder stone can prove fatal. That’s because when they are dislodged, they can block the tubes that lead from the kidney to the bladder, or from the bladder to the urethra. This causes pee to build up because it can’t get past. Your cat’s kidney or bladder could rupture, and it would die as a result. They can also cause grazes or cuts in the kidney, bladder, or the tubes that connect the urinary system together.

When your cat eats nothing but dry food, these crystals/stones form much faster.

UTI (Urinary Tract Infection)

cat toilet
Cats with UTIs struggle to go to the toilet.

When bladder or kidney stones damage your cat’s urinary tract, urinary tract infection often results.

A UTI is where bacteria enters through the urethra and enters a wound in the urinary tract. The area around the wound then becomes inflamed.

This happens because of the immune system’s histamine response. White blood cells find the bacteria and let out a signal to the rest of the immune system that something needs to be done. The body sends histamine there, which causes swelling by opening the tiny blood vessels nearby and allowing more blood in. On the one hand, this allows more white blood cells into the area, but it also causes a swollen lump.

Elsewhere in the body this might not be a problem. But the pipes that connect the urinary tract together are narrow and are easily blocked by this swelling. That’s why a UTI stops your cat from peeing. If kidney or bladder stones are present, they can continually cause small cuts and therefore continually cause UTIs too.

Dry food therefore doesn’t cause UTIs directly, but in a roundabout way, and after a long time.

Is Dry Cat Food Good for a Cat’s Teeth?

One of the reasons people recommend dry cat food is that it’s supposedly good for a cat’s teeth. The idea is that its rough outer surface brushes at your cat’s teeth and so gets rid of plaque.

This is partly true, but also less true than you might think. The rough outer surface of dry cat food can clean your cat’s teeth. It’s abrasive like a toothbrush with hard bristles.

The problem is that kitty kibble comes in very small chunks. Your cat doesn’t have molars like ours that are good for chewing food. It has sharp, pointy teeth, and it struggles to chew on small pieces of kibble. This means that your cat eats many of the individual biscuits whole without them having any abrasive effect on the teeth.

Beyond that, kibble may even be bad for your cat’s teeth. That’s because it contains lots of carbohydrates which can be partially digested in saliva. This sticky, slimy carb-and-saliva mixture adheres to your cat’s teeth and can damage them in the same way that candy damages our teeth. It can cause tartar formation and gum disease.

Do Cats Need Wet Food Every Day?

Feeding your cat wet cat food every day is better than feeding dry cat food every day. Again, your cat doesn’t drink a lot of fluid in a day, and nowhere near enough to make up for dry food. Feeding it wet food every day is therefore better.

Feeding your cat wet food on some days and dry food on others isn’t ideal, though. That’s because cats don’t typically opt for variety in a diet. In wild cat populations, kittens/young cats learn from their mother which prey to hunt. This preference lasts into adulthood. So, if your cat enjoys dry food, it will gorge itself on dry food days and leave its plate on wet food days.

If you don’t want to feed wet food every day for whatever reason, you could feed raw meat instead. There are commercial brands that sell raw tins of cat food which you could use, or you could feed your cat raw meat from a supermarket (although this isn’t always ideal).

Mixing Wet and Dry Cat Food

You could alternatively mix small amounts of dry food in with your cat’s wet food. There isn’t any strict nutritional need to do this, but if it helps your cat finish its meals, you could. You shouldn’t mix in large amounts of dry food as a permanent solution, though; it’s better if your cat transitions to eating nothing but wet food/raw food as soon as possible.

How to Change Your Cat’s Diet

If you feed your cat dry food, and you want to switch to wet food, don’t make the change overnight. If you do, your cat’s gut will react badly. Cats get used to eating certain things, and when you change what they eat, whether that change is good or bad, it can result in gastrointestinal distress. Owners changing their cats’ diets may see their pets vomiting or experiencing diarrhea and conclude that the change must be bad, but that’s not necessarily the case.

To avoid this problem, use the 80/20 method. This is where you make a gradual change rather than an all-at-once change. Here’s how it works.

  • In the first week, feed your cat 80% old food and 20% new food. Mix the new food into the old food so that your cat stands less chance of turning its nose up at the meal.
  • In the second week, feed your cat 60% old food and 40% new food.
  • In the third week, feed your cat 40% old food and 60% new food.
  • In the fourth week, feed your cat 20% old food and 80% new food.
  • In the final week, feed your cat nothing but new food—it should tolerate the food perfectly.

You should consult with a vet before you make any changes to your cat’s diet, whether in favor of wet food or dry food.