By Jennifer Copley (Last Updated 18 December 2011)
The wet (canned) versus dry (kibble) cat food debate rages on, and while some veterinarians say that either wet or dry food is fine as long as it’s high quality, others assert that cats should be fed primarily wet food for the following reasons:
- Dry food can have a dehydrating effect, which may lead to urinary tract infections (UTIs) and kidney disease.
- Dry food tends to be higher in carbohydrates, which increases the risk for inflammatory bowel disease, obesity, diabetes, and cancer in cats because they are obligate carnivores.
Dry Cat Foods Can Have a Dehydrating Effect
The moisture content in dry cat foods is approximately 5%-10%, compared to nearly 80% for wet food. Many cats fed primarily or totally on dry food spend their lives in a chronic state of low-level dehydration. This can lead to a higher density of minerals in their urine, which can cause urinary tract illnesses (UTIs) and may contribute to chronic renal failure (CRF), also known as kidney disease.
Some cats, particularly those that tend to be naturally slim and active and drink lots of water, do fine on premium, high-protein dry foods. Owners feeding dry food can decrease the risk of UTIs and kidney disease by encouraging more drinking. This can be done by:
- Keeping water bowls clean and providing fresh water each day
- Placing bowls of water at multiple locations throughout the house
- Purchasing a fountain-type water bowl
- Using glass, metal, or ceramic water bowls rather than plastic
Feeding Cats Dry Food Increases the Risk of Obesity
Cats are obligate carnivores and they require a high-protein diet for optimum health. Wet foods tend to include more animal-based protein, whereas dry foods are often higher in carbohydrates, which can lead to weight gain because cats have to eat more to feel that they have satisfied their protein requirements.
The fact that owners tend to free-feed dry foods (leave a full bowl out all day long) rather than having set meal times further increases the likelihood of obesity. Also, because cats prefer food that tastes strongly of meat or fat, starchy dry foods are often coated with either fat or a powder made from animal by-products. This makes the food so tasty that cats overeat.
Obesity predisposes cats to a variety of health problems, including diabetes, cancer, liver disease, and certain skin diseases. According to veterinarian Ron Hines (2009), 20%-40% of cats that are free-fed dry food become obese.
Wet Food, Dry Food, and Feline Dental Health
Does dry cat food keep a cat’s teeth cleaner? Some studies have found slight dental benefits associated with eating dry food. However, unless a cat is slim and active, drinks plenty of water, and eats only a premium high-protein dry food, the health risks of feeding nothing but dry likely outweigh the benefits. Veterinarian Jean Hofve (2010) recommends that at least 50% (and preferably more) of a cat’s total calories come from wet food.
Canned Wet Food and Thyroid Disease
Some research has linked pop-top cans, fish flavours, and by-products to thyroid disease in cats. Although it’s not known for sure, many experts have speculated that the rancid fish and by-products often used in cat foods, particularly cheap, low-quality brands, along with the materials used in certain types of cans, may contribute to health problems.
Hofve recommends purchasing cat food in larger cans rather than pop tops and refrigerating leftovers (store them in a glass container rather than the metal can). If refrigerated, food should be warmed to room temperature before serving – many cats will not eat cold food, as it is too far removed from the natural body temperature of prey.
Switching Cats from Dry to Wet Food
Most cats prefer wet food and are happy to gobble it down when owners provide it, but cats that love their dry food may have difficulty making the switch, particularly if they’ve been free-fed. To overcome this reluctance, Hofve recommends leaving dry food out for only an hour a couple of times a day. After the cat has become used to the new feeding schedule, try providing a little canned food before putting down the dry. If he’s hungry, he’s more likely to try it.
This article is provided for informational purposes only and is not intended as a substitute for veterinary consultation and care.
- Hines, R., DVM. (2009). “What Should I Feed My Cat.” 2ndChance.info/catfood.htm.
- Hofve, J., DVM. (2010). “Why Cats Need Canned Food” and “Does Dry Food Clean the Teeth?” LittleBigCat.com.
- Stuart, A. (Reviewed by M. J. Stickney, DVM, 1 May 2010). “Cat Food 101: What You Need to Know About Feeding Your Cat.” WebMD.com.