I often hear owners and veterinarians (myself included) say that canned food is generally better than dry for cats because the former is higher in protein. Well… I was doing some research for a previous post on feline nutrition and stumbled upon something interesting. In some cases, dry food has more protein than canned, even when comparing similar products made by the same manufacturer.
The first case I found involved a prescription, gastrointestinal diet made by a major manufacturer. Their canned variety contains 43.2% protein on a dry matter basis (meaning after the water has been removed, a necessary calculation when comparing dry and canned foods). Their dry version of the diet comes in at 56.8% protein, again on a dry matter basis. To see whether this finding was unique to this particular brand, I looked at another manufacturer’s prescription, gastrointestinal diet. Their dry food is 40% and canned food is 37.6% protein, both on a dry matter basis.
Hmmm. Perhaps protein levels being higher in dry versus canned foods had something to do with the nature of prescription, gastrointestinal diets. I next examined a high quality, over the counter maintenance food for adult cats made by a major pet food company. On a dry matter basis, both their “salmon” kibble and canned “salmon” diets were 33% protein.
Okay then, what about a brand of food that has a well-earned reputation for being one of the highest protein varieties available over the counter? The company’s dry Turkey and Chicken Cat/Kitten Food (it’s an “all life stages” food) has 55.6% protein while their canned version of the same food has 54.5% protein.
Based on this admittedly quick and dirty analysis, it sure looks like owners can’t rely on the overly simplified statement that canned foods contain more protein than do dry.
Unfortunately, comparing ingredient lists isn’t all that helpful either. Ingredients are listed in order of decreasing dominance in the food based on their weight which includes water content. The first few ingredients listed on the labels of the Turkey and Chicken Cat/Kitten Food mentioned above are:
(click image for larger view)
I don’t know about you, but I’d be hard pressed to say whether the dry or canned version of this food was higher in protein based only on these lists.
So, there’s no way around doing some math when it comes to comparing the protein content of dry and canned cat foods. Thankfully, the calculation involved is simple:
- Find the percent moisture and subtract that number from 100. This is the percent dry matter for the food.
- Divide the protein percentage on the label by the percent dry matter for the food and multiply by 100.
- The resulting number is protein percentage on a dry matter basis.
Keep in mind, however, that protein level is not the only characteristic that should be evaluated when picking out a cat food. In fact, the very attribute of canned foods that limits how high their protein levels can be — their high water content — is very beneficial for feline health.
Dr. Jennifer Coates