Essential Guide: Understanding Your Cat’s Food Diet

Vet’s Klinic Clinical Director and veterinary practitioner, Jenny Philip BVMS MRCVS, knows the importance of giving your cat a science based natural balanced diet, which gives them the nutrients they need to thrive knows first-hand how deficient some commercially prepared cat food brands can be from a nutritional point of view.

Currently 70% of UK cat owners feed a commercially prepared diet to their cat, of which half feed a mix of wet and dry cat food; the other 30% of owners feed table scraps, raw meat based diets or allow their cats to eat live prey.

Raw and live prey animal cat food diets are potentially very biologically appropriate. However, at home prepared diets are notoriously difficult to balance correctly and can be time consuming and inconvenient for most. Worryingly, a recent study in the US found 84% of these home prepared diets are deficient in multiple nutrients.

Even so, some commercially prepared cat food diet recipes are just as inappropriate; they may well balance better on paper but it only takes a glance at the back of a packet of some of these commercial cat foods to highlight their inadequacies.

For example, take the two best market leading dry cat food brands; the analytical constituents (this is the ingredients in the cat food) read 30-32% protein, 10% fat and 7.5-8.5% ash. What the manufacturer doesn’t need to declare is the carbohydrate content. Most of these dry diets are over 40% carbohydrate and rely on the carbohydrate to create the kibble structure. So why is a high carbohydrate content in a cats diet a concern?

Are Cats Carnivore or Omnivore?

Cats do not need a high carbohydrate diet, in fact it goes against their biological makeup

Cats are biologically different to us; they are classified as obligate carnivores. If you are a ‘Carnivore’ you derive your energy and nutrients from a diet exclusively or mainly from animal tissue. If you are an ‘Obligate Carnivore’ you depend solely on animal tissue as opposed to a facultative carnivore that, in the absence of meat, can choose to use non-animal sources for their nutritional requirements. In contrast, humans are classed as omnivores, deriving their energy from a variety of food sources, and dogs are a topic of controversy and can be classified as either omnivore or facultative carnivores.

The domestic cat’s natural diet consists of small rodents and mammals. On average a prey item is 62% animal derived protein, 10% fat with 14% ash, which is mainly mineral content from bone (see the table below).

Prey Species – Crude Protein% – Fat% – Ash%

  • Mouse – 62 – 11 – 13
  • Rat – 63 – 9 – 14
  • Small Bird – 62 – 9 – 15

This protein rich diet has caused obligate carnivores to evolve with completely different biochemical pathways for processing food and metabolising nutrients when compared to other species we are familiar with such as dogs or ourselves.

Cats Need Protein for Energy, Not Carbohydrates!

The universal source of energy to all cells in any creature is glucose. For humans and dogs glucose is readily available from breaking down the carbohydrate in our diets. However, for carnivores their diet of fat and protein requires them to obtain glucose in a different way. Hence cats have well developed pathways to convert the building blocks of protein, amino acids, into a source of glucose. These pathways exist in humans and dogs but they are part of a collection of pathways to create energy that can be altered dependent on the type of food ingested. For cats, even when a cat has not consumed any protein, their body cells still demand a source of amino acids for energy and, in the absence of dietary protein, they have to start utilising existing body protein, i.e. muscle mass, to maintain normal cell function.

Cats naturally in the wild would consume a high amount of protein in their diet, 62% if they consume a mouse. Comparing this with the commercial diet at 30% it doesn’t take an expert nutritionist to identify a massive discrepancy within their diet!

Don’t All Commercial Cat Foods Contain Protein?

Technically, commercially prepared cat food products do contain protein, but not all protein is created equal. The other important question that needs to be considered is where the protein originates from. Protein in a diet can come from animal tissue but is also found in many vegetables and grains. The only way of determining the source of protein is by analysing the composition (ingredient) list on the back of the packet. The list is ordered by weight in descending order, so to satisfy a cat’s biological requirements, a source of meat-based protein should be first on the list. For the two diets in our example the first three ingredients read: cereals, animal and meat derivatives (10%), vegetable protein extracts. Therefore, the protein declared in these diets is largely derived from non-animal sources. Other than the obvious fact that we have never witnessed a cat with a desire to stalk vegetables, why does this matter?

Cats Need Animal Protein for Health Reasons.

It matters because, cats require specific amino acids and vitamins in their diet, which are essential for normal cell function; some of these can only be obtained naturally from animal tissue. Arginine, Taurine, Cysteine and Methionine are amino acids used in lots of important processes in mammals but cats have to rely on a dietary source making them essential; this is not the case in dogs and humans as they can synthesis these molecules from others. For cats this process is not efficient and their daily requirements are much higher, consequently they utilise them faster than they can be created. Deficiencies can cause serious disease, for example taurine deficiency can cause heart disease and blindness. Commercial diets have to follow strict guidelines to ensure that these molecules are present in adequate amounts and in cases where levels are inadequate, the cat will need to take an artificial supplement to ensure they receive the right level of thee important vitamins and minerals. Surely the more logical and natural approach is simply to feed what the cat naturally requires- meat based protein!

How many of us have seen a black cat that has a reddish brown tinge to their coat?

This is something that many of us may have observed in passing without realising but is a classic example of the effects that a diet deficient in meat can have. Tyrosine is an amino acid only found in animal tissue that cats can’t synthesise themselves. However, it is not a necessity for body function and therefore is not a regulated requirement to be supplemented in commercial diets. Tyrosine is a key component of the pathway that creates melanin, the black pigments responsible for their coat colour; so in a deficient state a black cat turns brown.

Where is your cat’s protein coming from?

Even when animal protein is included in a diet the majority comes from rendered sources. Rendered meat or more commonly named ‘meal’ comes from animal tissue that has been heated for a prolonged time at extreme temperatures and pressures to remove the fat. Rendered meat is on average only 75% digestible. This means that for every 10g of rendered meat consumed only 7.5g can be utilised by the body. When you compare this to some of the new technologies using fresh meat as an ingredient, with 96% digestibility, this protein source certainly looks to be a more favourable ingredient. Furthermore, the carbohydrate content in commercially prepared cat food diets affects digestibility; the higher the carbohydrate content the less digestible the protein. There are several factors contributing to this but predominately carbohydrates accelerate gut transit hence reducing the time available to digest protein in the diet.

More importantly on this topic, as illustrated by the figures above, a cats natural diet does not contain large amounts of carbohydrate, therefore cats have evolved with a reduced ability to process and utilise carbohydrates.

Raw Cat Food – Why It’s the Best Diet For Your Cat, and What Are the Trade-offs For You?

The biggest myth surrounding cat ownership is that cats are worry free, self-contained and self-providing pets that require little or no maintenance. Cats are so good at giving people the impression of independence and self-reliance that people believe they don’t have to provide the highly focused attention to cats that, say, dogs require. The fact of the matter is that cats do require the same attention to detail that any dog does, and maybe even a little more, in some cases. This is especially true when it comes to probing the controversy regarding whether raw cat food is better that canned cat food or kibbles for your feline ward.

It’s a sad thing to look around our country these days and see so many people who have allowed themselves to become overweight and then have to deal with the consequential suffering and ill-health effects of obesity. Diabetes, shortness of breath, constant exhaustion from lugging around so many extra pounds and lowered self-esteem. Of course, the garment industry is singing happy tunes with all the extra thread they have to put together. There’s no shortage of explanations for why this situation has come about, but I think when it comes down to it we can only blame ourselves at the individual level for allowing such a condition to take root. After all, how many pounds overweight does one have to get before they realize that something’s not right and becoming a problem? 10, 20… 50 lbs? And how long does it take to realize that the magic pills, diets, elixirs and effortless, lose-weight-with-no-work-out machines are products being marketed to your ego, to separate you from your bank account, and not to solve your problem? No… the only way to find an ideal normality is with thorough research, discovery and a lot of hard work accompanied with a healthy life style change. But, enough sermonizing about the human condition. This is about cats, their eating habits and raw cat food.

One thing needs to come along with this discussion from the previous paragraph. Most people are not experts in animal nutrition and rely on others to lead them in the right direction. The source for most ‘experts’ available to a person for their daily decision making and selection of choices usually comes to us through the traditional media of radio, newspapers, television and now, the internet. Media offers two kinds of resources. Investigative reporting which is presented in newscasts or opinion pieces, and secondly, the marketing hype that provides commercial broadcast funding. The former is reliable enough to put credence into and might call for further research on your part if it interests you. The latter really only wants you to spend your money with them. That’s not necessarily bad… it does ultimately put people to work and provides many with an adequate, and even comfortable living. Unfortunately, the bottom line is… corporations only have one objective in the end. That is to feed their bottom line. Now recent events have caused many to reconsider the morality behind a corporations goals. But, as long as this market structure is the paradigm for our economy, the ultimate goal for big business will always be to maximize their profit-loss statements towards the profit end of the spectrum, any way they can get away with, and at your expense… literally.

So, what does this have to do with cats and if raw cat food is what you should be feeding them? Simply put, most people rely on the marketing hype to base their decisions regarding the food they feed their pets. Which is exactly the wrong source for basing such a critical decision. Take the cat for example. It’s not only a scientific fact, but a cultural one also, that the cat is described as an obligate carnivore. This defines cats as creatures who derive most of their food nutrients from the animals they hunt and consume (raw cat food). When a cat devours it’s prey, she will eat everything including not only muscle meat, but the brains, organ meat and the stomach and its contents which may consist of grasses and grains. One thing she doesn’t do is fire up a stove and saute or bake her dinner, or prepare a nice sauce to go with it. She eats it raw. Cultural purists use this description as an argument that feeding cats store bought, mass produced canned or dry cat food is doing your cat a disservice by depriving her of the natural nutrients she would normally get in the raw cat food she captures in the wild, and for which she was biologically designed.

Pottenger’s cats
Francis M. Pottenger, Jr. (1901 – 1967) was the son of Francis M. Pottenger, Sr., the physician who co-founded the Pottenger Sanatorium for treatment of tuberculosis in Monrovia, California. Between 1932 and 1942 he conducted what is know as the Pottenger Cat Study. One part of this study was what effect heat had on the nutrient value of raw food. In other words, what happens to food when you cook it.

“Pottenger used donated laboratory cats to test the potency of the adrenal extract hormones he was making. The adrenal glands of these cats were removed for the experiments and Pottenger noted that most of the cats died during or following the operation. He was feeding the cats a supposedly nutritive diet consisting of raw milk, cod liver oil and cooked meat scraps of liver, tripe, sweetbread, brains, heart and muscle.

When the number of donated cats exceeded the supply of food available, Pottenger began ordering raw meat scraps from a local meat packing plant, including organs, meat, and bone; and fed a separate group of cats from this supply. Within months this separate group appeared in better health than the cooked meat group. Their kittens were more energetic and, most interestingly, their post-operative death rate was lower.

At a certain point, he decided to begin a controlled scientific exploration. Pottenger conducted studies involving approximately 900 cats over a period of ten years, with three generations of cats being studied.