The risks of raw feeding: all-meat diets
Homemade diets for our pets come with some associated risks, in particular concerning their nutritional balance. Manipulation of raw meat is also a potential risk of raw diets.
In order to help you better understand these risks and mitigate them, I’m starting a series of articles about the risks of raw feeding.
In this first article, I’m going to talk about probably the biggest mistake you can make when feeding a homemade diet: feeding only meat. As we will see, feeding an all-meat diet could kill your cat.
What’s an all-meat diet?
As its name suggests, an all-meat diet contains only meat. Specifically, it’s a diet that doesn’t contain any source of calcium.
An all-meat diet might be a cooked diet—which is often the case with recipes vaguely based on human diets—and composed of ⅓ meat, ⅓ vegetables, and ⅓ carbs.
It can also be a raw diet: that is often the case when beginners start without taking the time to research a well-formulated diet. In fact, it’s known that cats are carnivores and so they should eat meat. However, as we will see in this article, they shouldn’t eat only meat.
The consequences of an all-meat diet
As an all-meat diet doesn’t contain any source of calcium, the consequence is that—as you would expect—the diet will be calcium deficient.
This calcium deficiency will lead to nutritional secondary hyperparathyroidism, also known as the “all-meat” disease.
Calcium is an essential mineral for cats, as their body isn’t able to synthesize it. Therefore, it must be provided in the diet. If the calcium levels in the blood drop, this may cause hypocalcemia, with symptoms including seizures, tetany, cardiac arrest, and death. However, to avoid hypocalcemia, the body tightly regulates the calcium in the blood: if it’s not provided in the diet, the body will take it from its reserves. These calcium reserves are the cat’s bones (as they are mainly composed of calcium).
So, calcium deficiency in the long-term will cause a decalcification of the bones: a cat eating an all-meat diet will have a low bone density. Low bone density means that bones are brittle and fragile. This can cause spontaneous fractures and bones deformation, especially in kittens. In the worst case, it can lead to death. [1]
What is particularly insidious with calcium deficiencies is that the blood calcium levels are so closely regulated that a blood test won’t show that something is wrong until at a very advanced stage.
The best way to verify that there isn’t any calcium deficiency is to audit the diet to verify that it contains enough calcium to fulfill the nutritional requirements of the cat.
The consequences of a calcium deficiency appear much more quickly at demanding life stages such as growth, gestation, and lactation.
A kitten not only needs calcium for normal body functions but also to build the bones for growth. Similarly, a gestating or lactating queen has increased calcium requirements to grow the kittens or produce milk.
In the case of nutritional secondary hyperparathyroidism, kittens were affected after only one to three months of eating a diet without calcium. [2][5][6]
For adults, cases have been reported in dogs after one year and a half to several years on a diet deficient in calcium. However, radiological evidence of decreased calcium density in the bones is visible after 10 weeks on an all-meat diet. [3][4][8]
Why do people feed an all-meat diet?
People feed all-meat diets due to two main misconceptions. The first one is anthropomorphism: people try to feed their cats the same way that they eat. However, cats have much higher calcium requirements than us humans. Here are some numbers to give you an idea:
A human adult needs 900 mg of calcium a day, and a 4 kg cat needs 180 mg of calcium a day. If you translate the needs of cats for a 60 kg human, that would be 2700 mg of calcium a day, so 3 times more than the recommendation for human adults. [7]
The second misconception probably comes from an idealization of carnivores that would eat exclusively meat. However, that's not correct as the prey that cats eat are not made of only meat aka muscular tissue, but they also have organs, bones, skins,... The bones are the part of their prey that brings their calcium in the wild! So, while a cat cannot survive eating only meat, it can survive eating only animal products.
What’s a calcium source?
Now that we understand the danger of a diet without calcium for our cats, let’s look at the possible source of calcium in a homemade diet.
The most natural source of calcium will be the same one as the one consumed by wild cats: raw meaty bones. A word of caution as cats can’t eat all bones: they should be meaty (with meat around) and raw, as cooked bones can splinter and be dangerous. Finally, they should also be adapted to the size of your cat, as bigger bones may break their teeth. You can read more about raw meaty bones in this article.
Bones can also be fed ground (and raw). They can also be found in the form of a bone meal, which is cooked and finely-ground bones.
Another natural source of calcium is fine-ground eggshells, as they are made of 97% calcium carbonate.
You can also directly use a calcium supplement like calcium carbonate.
In a cooked diet and some raw diet, it’s common to feed a meal completer that will bring calcium and other minerals and vitamins needed in addition to the meat.
The quantity of calcium that you need to add to the diet depends on your cat’s nutritional requirements and need to be precisely calculated.
As I mentioned in a previous paragraph, it’s important not to make any anthropomorphic analogy: you might think that dairy products could be a good source of calcium for cats but, in fact, they are not adapted. This is because cats become lactose intolerant as they grow up and because milk, cheese, and yogurt don’t contain enough calcium compared to cats' needs. The quantity of dairy that would be needed to satisfy their requirements would cause gastrointestinal upset and bring far too many calories into the diet.
For example, to get enough calcium, a cat would need to eat more than an entire yogurt every day, which is a huge quantity and would bring more than a third of their daily calorie requirement.
Slow transition for kittens
When you transition a kitten to a raw diet, it’s important to always feed a source of calcium.
I personally recommend directly introducing raw meaty bones or another calcium source. In fact, waiting several weeks before introducing raw meaty bones could compromise the growth of your kitten or even put them at risk of nutritional secondary hyperparathyroidism.
To conclude, calcium in a homemade diet is absolutely essential. If you see any recipe for cats without any source of calcium don’t feed it to your pet as it could be really dangerous. While common sense may say that cats need to eat only meat, this is actually erroneous and meat is not a synonym of animal products that also contains organs and bones.
Sources
[1] Parker, V. J., Gilor, C., & Chew, D. J. (2015). Feline hyperparathyroidism: pathophysiology, diagnosis and treatment of primary and secondary disease. Journal of feline medicine and surgery, 17(5), 427–439.
[2] Taylor, M. B., Geiger, D. A., Saker, K. E., & Larson, M. M. (2009). Diffuse osteopenia and myelopathy in a puppy fed a diet composed of an organic premix and raw ground beef. Journal of the American Veterinary Medical Association, 234(8), 1041–1048.
[3] de Fornel-Thibaud, P., Blanchard, G., Escoffier-Chateau, L., Segond, S., Guetta, F., Begon, D., Delisle, F., & Rosenberg, D. (2007). Unusual case of osteopenia associated with nutritional calcium and vitamin D deficiency in an adult dog. Journal of the American Animal Hospital Association, 43(1), 52–60.
[4] Verbrugghe, Adronie & Paepe, Dominique & Verhaert, Leen & J, Saunders & J, Fritz & Janssens, Geert & Hesta, Myriam. (2011). Metabolic bone disease and hyperparathyroidism in an adult dog fed an unbalanced homemade diet. Vlaams Diergeneeskundig Tijdschrift. 80. 61-68.
[5] Won, D. S., Park, C., In, Y. J., & Park, H. M. (2004). A case of nutritional secondary hyperparathyroidism in a Siberian tiger cub. The Journal of veterinary medical science, 66(5), 551–553.
[6] Lenox, C., Becvarova, I., & Archipow, W. (2015). Metabolic bone disease and central retinal degeneration in a kitten due to nutritional inadequacy of an all-meat raw diet. JFMS open reports, 1(1), 2055116915579682.
[7] https://www.anses.fr/fr/content/le-calcium
[8] NRC (2006). Nutrient requirements of dogs and cats. Washington, DC: National Research Council, National Academy Press.