The study demonstrated kitties have a daily calorie ‘intake target’ that is equal to 52 percent protein, 36 percent fat and 12 percent carbohydrate.
According to lead study author Dr. Adrian Hewson-Hughes:
“This is a fascinating discovery and we are intrigued to know more about why cats have the ability to do this. It is particularly remarkable that, even after thousands of years of domestication, cats still select a diet nutritionally similar to their natural prey.”
According to its authors, the Geometric analysis of macronutrient selection in the adult domestic cat, Felis catus is the most extensive study of macronutrient regulation ever conducted on any carnivore. (Macronutrients are the nutrients animals need in large quantities, like protein, fat and carbohydrates. Micronutrients are those needed in smaller quantities – primarily vitamins and minerals.)
The results of this study are extremely exciting, but not surprising to those of us who understand the importance of providing species-appropriate food to companion animals.
Food Used in the Study
The study was conducted to determine if adult 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).
From the study:
Most domestic cats are fed commercial pet foods by their owners. Some of these products are moist and others are based on a dry formulation.
As well as differing in water content and texture, there are macronutritional differences between wet and dry commercial foods, notably a higher carbohydrate content of dry foods (required for their manufacture). We have therefore built into the experimental designs an investigation of the nutritional consequences of these different food types.
Our results show strong nutritional regulation, reinforcing the fact that macronutrient regulation is common across trophic levels [feeding positions in a food chain] and providing important information for the design of domestic cat nutritional regimes.
For the experiments, six dry cat food formulas and six canned formulas were used.
The dry food formulas were manufactured by Mars Petcare based on commercial recipes. They contained poultry meal, maize gluten, ground rice, wheat flour and beef tallow to fulfill the three macronutrient requirements of protein, fats and carbohydrates.
The canned foods were also manufactured by Mars Petcare using commercial recipes and contained chicken breast, soya protein isolate, lard and wheat flour.
All the formulas (kibble and canned) contained added vitamins, minerals, taurine and L-methionine to meet the National Research Council (NRC) and Association of American Feed Control Officials (AAFCO) guidelines for adult feline maintenance.
Only kitties fed dry food from weaning were used in the dry food experiments; only cats weaned on canned food were used in the wet food experiments.
While this research didn’t include them, study authors recommend future projects incorporate other dietary factors like water content, texture and added flavorings to determine to what extent those features impact how cats select the food they eat.
- The cats in the study demonstrated a maximum tolerable level (ceiling) of carbohydrate intake that is 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 as follows:
- 100 calories or 52 percent from protein
- 67 calories or 35 percent from fat
- 24 calories or 12.5 percent from carbs
- 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.
Research Proves It: Cats and Carbs Don’t Mix!
Cats are obligate carnivores, meaning they have nutritional requirements that can only be met with a diet based on animal tissue. The macronutrient profile for cats is high in protein and fat, consistent with a meat-based diet.
According to study authors:
The carbohydrate ceiling explains many of the intake patterns seen in both dry and wet diet experiments and suggests that cats may only be able to process ingested carbohydrate up to a certain level.
The feline body is specifically designed for a low carb diet. Indicators your kitty isn’t equipped by nature to process a lot of carbohydrates include:
- No taste receptors for sweet flavors
- Low rates of glucose uptake in the intestine
- No salivary amylase to break down starches
- 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 and are found in the stomachs of prey animals.
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 a cat food with high carb content, she’s on track to develop digestive disease and other serious conditions like diabetes and pancreatitis related to eating a diet unfit for her species. And certainly, too many carbohydrates aren’t the only problem with most processed pet foods.
Pet Food Industry Response
To answer research findings on the appropriate way to feed carnivorous pets, and in response to growing consumer demand, an increasing number of pet food manufacturers are introducing grain free formulas that are higher in protein content.
Unfortunately, the type of protein used in most affordable pet foods is of poor quality. Whole food protein sources (animal meats) aren’t cheap, after all.
Much of commercial pet food protein is derived not from human-grade meats, but from crude, rendered or non-meat sources. The digestibility and absorbability of low grade protein sources is questionable at best. This means your pet’s body won’t get optimal nutritional benefit from the protein in the majority of commercially available pet foods.
I can only assume as more protein is added by pet food industry giants, the quality will decrease proportionately to insure the products remain affordable for consumers and profitable for pet food companies.
Even more concerning to me is that while science is proving cats need more protein and manufacturers are beginning to deliver high protein products, they are still not biologically correct.
High protein diets that are dehydrated or extruded (made into kibble) do not contain adequate moisture content. Cats were designed to get most of the moisture their bodies need from the water found in fresh prey (which is about 70 percent water). When cats eat dry food, their organ systems become stressed and they can end up with kidney, liver and digestive stress.
What About Your Favorite Feline?
If you’re convinced it’s time to transition your carnivorous kitty to a more biologically-appropriate food, there are a few different ways to approach it.
My favorite, as regular readers of my newsletter know, is to learn how to prepare your pet’s meals at home with ingredients you select based on balanced recipes from either Real Food for Healthy Dogs and Cats or another expert nutritional source. Our feline recipes are designed to be about 60 percent protein (including organs), 27 percent fat and 13 percent carbohydrate (veggies), which mimics their natural requirements.
If you don’t feel you have the time or resources right now to prepare homemade meals for your cat, the next best thing is to feed a commercially prepared, balanced, raw diet. These diets are usually found in the freezer section of small or upscale pet boutiques – not in the big box pet stores. You can also find a selection online. Unfortunately, this option is just too costly for many pet owners.
If neither of these choices work for you, do not despair!
No matter what you’re currently feeding your kitty, you can take baby steps up the pet food quality ladder. Take a look at my video/article 13 Pet Foods – Ranked From Great to Disastrous to find out where your pet’s food ranks, and how you can make gradual improvements to your beloved kitty’s diet over time.
I also recommend you read here for some great tips on how to decipher the labels on your cat’s pet food like a pro. (The article is about dog food labels, but the information provided can be applied to cat food just as easily.)