By Dr. Becker
Recently, a team of scientists from the U.K. and Australia published some fascinating research on how domestic cats choose the food they eat.1 What the researchers discovered was that given options, kitties learn to choose food based on its nutritional value, not how it smells or tastes.
Now, this will probably come as a surprise to many of you with finicky felines who at times seem impossible to please, but hang in there with me as we explore the insights this new research provides.
Cats DO Go for Flavors and Aromas First, BUT …
The research team's goal was to study "macronutrient balancing" in domestic cats, and specifically, to determine to what extent the smell, taste and texture of food influences what they choose to eat.
Macronutrients — carbohydrates, fat, and protein — provide the body with energy. Prior studies have shown that not only wild herbivores and omnivores, but also carnivores like cats are driven by nature to forage or hunt for food that provides the ideal balance of macronutrients.
For the study, the scientists formulated three different flavors of wet food with about the same protein-to-fat ratio. The foods were the consistency of porridge. One contained fish, another rabbit, and the third, orange flavoring.
They offered the three foods to a group of male and female cats, all of which initially showed a preference for the fish-flavored food, followed by rabbit, and with the orange-flavored stuff coming in a distant third.
However, over time, the kitties learned about the nutrient content of the three different foods and began choosing the foods that allowed them to meet their unique nutritional requirements for protein and fat.
Through Exposure, Kitties Learn the Nutritional Value of Food
As lead author Adrian Hewson-Hughes, Ph.D., explained to Discovery News (Seeker):
"Cats initially selected food based on flavor preferences, but after 'learning' (due to prior exposure) about the nutritional composition of the foods, cats selected foods to reach a particular target balance of protein and fat regardless of added flavors."2
As a result, over time some of the kitties ate more of the not-so-tasty orange-flavored food because it had the right protein-to-fat ratio. The fish and rabbit-flavored foods didn't have the precise nutrient ratio the cats instinctively knew they needed.
Specifically, the cats' ideal protein-to-fat ratio was about 1 to 0.4, which means about 50 percent of their energy is derived from fat, and 50 percent from protein. From the study:
"What is remarkable given the unusual nature and properties of the foods offered in these experiments — 'porridge-like' consistency, added flavours/aromas, different P:F [protein-to-fat] compositions and animal- or plant-derived protein sources — is the extent to which the balance and amounts of protein and fat intakes do converge …
This indicates that macronutrient balancing is a powerful driver of food selection in cats and points to the ability to detect and respond to post-ingestive macronutrient signals that are distinct from sensory aspects contributing to the apparent palatability of foods."3
Loosely translated, cats seem to receive signals from their bodies during and after eating, that provide information about the quantity and quality of nutrition they are ingesting, and therefore, the type of food they need more of, or less of, at future meals.
They will then choose the food their bodies need, regardless of taste, smell, or texture.
Another Good Reason Your Feline May Be Picky at Mealtime
As lead author Hewson-Hughes also told Discovery News:
"Cats can display neophobia. This means they are unwilling to try a food that is new or different to their normal food, which may make them appear fussy."4
Cats are obligate carnivores (also called strict or hyper carnivores), meaning they evolved to eat a diet of almost exclusively animal meat. Since for cats in the wild, eating a strange new food could lead to digestive problems or much worse, neophobia (fear or dislike of anything new or unfamiliar) makes perfect sense and helps keep them alive.
In addition, domestic kitties can recognize bitterness at the molecular level, which means they are able to detect rancidity with extreme accuracy.
The takeaway? Each time you feed Mr. Whiskers, he's learning about the value of the nutrition in his meal and whether he needs more or less of it. That could mean the food you've been giving him for weeks and that he initially seemed to love, isn't so enticing to him now.
In addition, if you've offered him a new type of food, he's probably balking due his natural tendency toward neophobia.
And on top of that, his acute sensitivity to "off" ingredients may also cause him to back away from the bowl. When you consider all that's going on when your feline family member strolls up to his food bowl, is it any surprise he sometimes turns up his nose and walks away?
Cats and Carbs
By now, you may be wondering why your cat seems to love treats. It's true many kitties gobble up store-bought treats, which are typically non-nutritious junk food, but it's probably because they get them only sporadically (or perhaps because they're bored or simply conditioned to accept treats).
However, based on their ability to choose nutritionally appropriate foods, it's doubtful any healthy cat would want to eat nothing but carbohydrate-laden treats all day. The fact is, the feline body is specifically designed for a low carb diet.
Cats aren't equipped by nature to process a lot of carbohydrates, which is why they have no taste receptors for sweet flavors, low rates of glucose uptake in the intestine, no salivary amylase to break down starches, and reduced capacity of pancreatic amylase and intestinal disaccharidases.
In other words, cats don't produce the enzymes required to digest carbohydrates. The only carbs felines eat in the wild are pre-digested by prey animals. You'll note carbohydrates aren't even mentioned in the study results, because the three foods the researchers formulated contained only negligible amounts. Doesn't it make you wonder why so many commercial cat foods are loaded with carbs?
In my opinion, many of the illnesses we see in cats today are attributable to low quality, biologically inappropriate commercial pet food formulas.
If your kitty's body is incapable of digesting a heavy carbohydrate load, and she's eating cat food with high carb content, she's at increased risk for digestive disease and other serious conditions, like diabetes and pancreatitis related to eating a diet unfit for her species.
Given the Choice, Cats Self-Select Foods Low in Carbohydrates
In an earlier study also led by Hewson-Hughes, the research team set out to determine if domesticated cats, given a choice, deliberately select food that is biologically appropriate for them (similar to the prey they would hunt and eat if they lived in the wild).5 The results were fascinating:
- The cats demonstrated a maximum tolerable level of carbohydrate intake under 25 percent.
- Given the option, the cats exclusively chose high-protein food over high-carb food even when there was less of the high-protein food available.
- Cats offered a choice of three foods with variable amounts of protein, carbs and fat mixed them to achieve a daily intake of 52 percent protein, 35 percent fat and 12.5 percent carbohydrates.
- When the cats were restricted to a high-carbohydrate food, they did not eat enough of it to get the targeted amount of protein (52 percent). The same happened with cats confined to a high-fat food — the target intake of protein was not achieved.
- Cats restricted to a high-protein diet ate more than the target protein intake, probably to gain energy. This suggests cats are able to eat even higher levels of protein than the target 52 percent.
- Experienced cats eating dry food increased protein intake and ate less carbohydrates than naïve cats offered the same choices. This indicates given the option, cats learn to avoid eating excessive amounts of carbs.
How to Keep Your Own Cat Well-Nourished
The goal in feeding your cat a diet she can truly thrive on is to mimic her ancestral diet as closely as possible. That means the best food you can offer your kitty is a nutritionally balanced, fresh homemade diet.
Of course, it's very important not to wing it when preparing your pet's meals at home, so, it's critically important that you know your homemade diet is balanced. The great thing about homemade raw diets is you get to handpick the ingredients. You know the quality of the meat you're using. With homemade food, you're in complete control of every ingredient that enters your kitty's body.
And of course, raw food is just that. It's raw and unadulterated. It contains all of the enzymes and phytonutrients that are typically destroyed during food processing. If you're not ready or able to prepare pet meals yourself at home, take a look at From Best to Worst - My NEW Rankings of 13 Pet Foods for additional options for providing your feline family member the food she would choose for herself if she could.