Is canned food or dry food better for cats?

by Dr. Wendy A Shiao, VMD
March 29, 2016

When I was a child growing up in Arizona, my dog's veterinarian told us that dry food was better for his teeth than canned food. I was young and impressionable, not to mention the fact that by that time I was already dreaming of becoming a veterinarian when I grew up, so vets were like gods to me when it came to pet health and I accepted everything they said as law.

My dog, a German Shepherd/Collie mix (half German Shepherd, a quarter Collie, and a quarter unknown) we adopted as a six-week-old puppy, ate nothing but dry dog food his entire life. No canned food, and no table food. He stayed very healthy except for one minor issue - Collie nose, which was attributed to a combination of his genetics and his intensive sun exposure due to living in Arizona, not to his diet. As he got older he also had a problem with hip dysplasia/arthritis in his hips but that was also attributed to genetics more than anything else. He lived to be 12 years old and was put down when the pain from his arthritis kept worsening and became unmanageable, but he was otherwise very healthy all his life.

My parents did not allow me to get a cat while I was growing up, so it wasn't until I got married and left home to attend veterinary school in Pennsylvania that I got my first cat. Soon after that we adopted two more cats and were a happy 3-cat household. Because my dog back home did so well on the dry dog food our vet suggested, and we were told the same thing for our cats, plus dry food was much more affordable than canned food for a poor vet student, we fed our cats a diet of mostly dry food with small amounts of canned food or tuna fish as an occasional treat. What I didn't realize back then was that dry food was not in fact the best diet for a cat. One of my two male cats had recurring urinary blockages (a life-threatening emergency medical condition), the other died of kidney failure when he was only six years old. My female cat, though spared of urinary problems as far as we could tell, developed feline asthma at a very young age.

Problems with Dry Cat Food

Cats, unlike dogs, do not have a well-developed thirst drive due to their origin as a strict carnivore living in a desert environment. Their natural diet consisted of prey animals that they caught and ate raw, which provided nearly all the water they needed without drinking much water. When pet cats are fed a dry food diet, they simply do not drink enough water to compensate for the lack of water within their food. Too many of them will succumb to urinary problems when kept on such a diet long term. This is the biggest but not the only problem with dry cat food.

Another problem with dry cat food is that it tends to contain more plant-based ingredients than canned cat food does. As obligate carnivores, cats do much better on a meat-based diet. They can digest and absorb nutrients from meat better than they can fruits, vegetables, or grains.

Additionally, processing destroys nutrients, and dry kibbles are a far-more processed form of food than canned food. Even more nutrients become lost once you open a bag of food and leave it sitting in your pantry for up to months until the bag is finished. Canned food, on the other hand, is less processed to begin with and each can is typically finished within a day or two of being opened, so more nutrients are retained.

As a general rule, canned food is a better choice than dry food for your cat.

But, what if you cannot afford or cannot manage feeding your cat canned food for whatever reason? Canned food, unfortunately, is more costly than dry food. And you simply cannot beat the convenience of feeding dry kibbles. Or maybe you're reading this but you're not the one making pet food decisions in your family and are unable to convince the person who is. Or you might have a cat that you're not yet able to transition to canned food. There are a number of things you can do to minimize some of the problems with feeding your cat dry food.

Ways to Improve a Dry Food Diet

First and foremost, you need to do everything you can to get your cat to drink more water if he's on a dry food diet. Fortunately, there are in fact many ways to help increase your cat's water intake, such as using a water fountain, trying different water dishes (many cats prefer a shallow, stainless steel dish, for example, because it doesn't touch their whiskers while they drink and doesn't impart any taste to the water), having multiple water dishes strategically placed around your cat's living space for easy access, using filtered instead of tap water to remove the taste of chlorine from the water, etc. You can also try giving your cat homemade unsalted/unseasoned chicken broth to drink. Some cats won't drink much water but will drink plain chicken or other meat/bone broth which has the added benefit of extra nutrients (including taurine) in addition to its water content.

Secondly, choose a high-quality dry food that has a higher meat-based protein content. A grain-free cat food is better in theory, but you should make sure that the grain isn't simply being replaced by other types of high-carbohydrate plant ingredient such as potatoes. You want as much of the food to be animal-based as possible, not plant-based.

Once you open a bag of cat food, it starts to degrade. Oxygen, light, heat, and moisture will all speed up the rate of degradation. The best way to store the unfinished food is to leave it inside its original bag, and put the entire bag into an airtight container in a cool, dry place. You should not pour the food out of the bag into a storage container. The original bag the food came in is designed to keep the food fresh longer, so leave the food in there. If you don't put the bag into an airtight container, you should at least squeeze out as much air as possible after each use, fold down the top of the bag, and use a large clip to keep the bag closed.


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