Here's the extent of my knowledge about pet food:
Every morning, I feed the cats heaping spoonsful of a premium brand food. If the cats eat the food, I am grateful and make a note: The cats liked today's food!
The next morning, armed with the knowledge from the previous day, I serve the cats the exact same brand and flavor. The cats get all huffy and peevish and refuse to eat. I spy them skulking around, all surly and offended, calling their cat lawyers on their little cat cellphones to consider taking legal action against me. Such an affront! This cannot stand!
I know what you're thinking: I should get a dog. This never is an issue with dogs. For reasons I will not belabor, this is not an option.
So I was interested to read a recent study that involved Jean Hall, a professor in the Carlson College of Veterinary Medicine at Oregon State University. Hall and her colleagues on this study ran what amounts to a blind taste test on pet food and came to some surprising conclusions, particularly in relation to cats.
Actually, the work involved in just designing this experiment, performed at the Kansas-based Pet Nutrition Center of Hill's Pet Nutrition, is mind-boggling: The researchers wanted to see what sort of diet dogs and cats would prefer when given a choice between meals that essentially tasted the same. So the researchers set about designing four meals that had different nutritional balances: One diet, for example had more fat than the others. Another diet had more carbohydrates. Another one had more protein, and so on.
But then the researchers had to figure out ways to make the meals taste the same, although I am not sure I want to know exactly how the researchers determined this. (This is the sort of scientific detail that sometimes is delegated to graduate students, God bless these foot soldiers for science.)
The test itself involved monitoring 17 adult dogs and 27 adult cats over 28 days. (It involved dry food, which is easier to track and measure.) Food container placement was changed daily, to account for the "bowl position bias," in which Rover decides he prefers to eat from the first bowl from the left. The dogs were allowed to eat for one hour a day, and their caloric intake was monitored so they would eat enough to maintain health but not enough to go tubby. The cats had access to their food bowls for 23 hours each day and presumably were busy dialing their lawyers during that 24th hour.
It turned out that given their druthers, dogs preferred the diets that were heavier on the fat; they preferred a diet that was 41 percent fat and 36 percent carbs. No surprise there.
But the cats were contrarian (again, no surprise). Despite a pet food industry that's been emphasizing protein-heavy feline diets, cats preferred the diets that were heavier on the carbs, opting for a diet that was 43 percent carbs and 30 percent protein. Not a single dog or cat chose to get the highest percentage of its calories from protein. (The Pet Nutrition Center of Hill's Pet Nutrition Inc. helped support the research, which was published recently in the Journal of Experimental Biology.)
"This new knowledge is going to challenge some people," Hall said. "It's new knowledge. It's credible. It's statistically valid. You have to consider it."
She said protein tends to be the most expensive ingredient in pet food. So, if pets don't need as much protein as earlier thought, why pack their food with it?
And the issue takes on some added urgency in the case of older cats, who can be prone to kidney disease. In essence, younger cats are more able to dispose of excess protein a lot better than older cats can — and that can add to the stress that older feline kidneys already endure, Hall said.
The findings also raise this intriguing question: What physiological signals are the animals responding to when they decide which foods to eat? "That's a whole new field," Hall said.
Are the pets eating the food that their bodies tell them best matches their needs? If that's the case, how does that signal get to the brain?
Those are the kinds of questions that keep Hall engaged in these studies: "I enjoy this. I enjoy looking at what you eat and how it maintains long-term health."
And there also is the sense that there's still lots we don't know about pet nutrition — or nutrition in general, for that matter.
"Everybody thinks they know a lot about pet food," Hall said, "but there's a lot we don't know." (mm)