How Are A Cat’s Nutritional Needs Different Than A Human’s?
Humans are omnivores. This means that our bodies can digest and use foods sourced both from plants and animals. Humans can survive on a large variety of different foods and diets.
On the other hand, cats are carnivores, obligate carnivores to be exact (source). They need to eat meat to survive. Their diet should be high in animal protein, high in moisture, moderate in fat, and low in carbohydrates. A small amount of plant matter can be digested and even used as dietary fiber, but large amounts can cause strain on the cat’s body.
Surviving Vs. Thriving
There is a difference between surviving and thriving. Surviving just means that the body is still alive. The body can become injured or diseased and continue to survive. Many humans and pets live for years with chronic diseases.
Thriving is another story. Thriving is when the body is working optimally, and no disease is present. A cat can survive when fed a diet that is high in plant matter, but they can’t thrive on it.
To put this into perspective, just imagine, as a human, that you were put on a diet that was mostly dirt. It’s a new, crazy, imaginary fad diet. Worms do it, why can’t we? Technically, you can eat dirt as a human.
If you ate dirt, your body would do the amazing things it was designed to do, and you would probably even squeeze out a little bit of nutrition in there somewhere. However, you would probably start to notice digestive issues after a while, which would eventually progress to more serious health concerns. If you have good, rich soil in your area and you are in good health to start with it could take a while to see any serious problems.
The dirt diet for humans is kind of what it is like to put a cat on a diet that is mostly made of plants. Just like humans can’t digest dirt the way worms can, cats can’t digest plant matter very well. Cats are carnivores. Different species, different rules. Sure, cats may get some benefit from plant matter, but the risk for chronic disease goes up.
Cats Are Carnivores Proof #1: Choice Of Diet In The Wild
When cats are left to choose what they want to eat for themselves, they hunt other small animals. Their chosen prey tends to be rodents, small birds, and insects. These smaller animals are eaten whole (source), that means fur, bones, organs, etc. Occasionally cats will be seen nibbling on plant life, but this makes up a very small portion of their diet. Some plants are very dangerous, such as the lily and it’s relatives.
Cats Are Carnivores Proof #2: Meat-eater’s Teeth
A cat’s teeth are thin and pointed. They are used for ripping and tearing meat – not for chewing (source). Often cats will chew their food as little as possible before swallowing it. A cat’s jaws move only up and down (not side to side), and they have powerful muscles in their necks for swallowing meat.
Eating vegetation requires rigorous chewing. Animals that naturally eat plants have large, flat molars that are made for grinding plant matter. They also can move their jaw from side to side to grind those plants up more efficiently.
Cats Are Carnivores Proof #3: Short Digestive Tract
Since cats are carnivores, their digestive tract of a cat is quite a bit shorter than that of a plant-eating animal. Cats eat their prey whole (meaning feces and bacteria still inside), so it makes sense that they would need to digest their food quickly. The longer the food is in the digestive tract, the more time for bacteria to build up and potentially cause illness. On average, the entire journey of the food from the mouth to the anus is 10-24 hours for a cat (source) which is less than half of the 2-5 days it can take in a human (source).
Cats Are Carnivores Proof #4: Lack of Correct Enzymes
Digesting vegetation requires certain enzymes to break down the cell walls of the plant. Animals that naturally eat plants produce an enzyme called cellulase in their saliva that helps begin to break down the plant matter.
Since cats are carnivores, they do not produce cellulase (source). Instead, a cat’s pancreas must produce a different enzyme called amylase to help digest plants. The cat’s pancreas is only designed to create a small amount of amylase as there is naturally very little plant matter in a cat’s diet. When a cat’s diet is high in plant matter, the cat’s pancreas becomes stressed from having to produce enough amylase to digest that plant matter.
Cats Are Carnivores Proof #5: Inability To Create Certain Amino Acids And Fatty Acids
Amino acids are found in every food whether plant or animal based. These are the building blocks of proteins and fats that are needed to sustain life. Sometimes an animal’s body can create necessary amino acids and other times they must be found in the food the animal eats. When an animal cannot create a certain amino acid it needs, that amino acid is considered an essential amino acid for that animal. There are also essential fatty acids (fatty acids that an animal’s body cannot produce).
Cats have essential amino acids and essential fatty acids that can only be found in meat (source). Taurine and arginine are examples. Cats also cannot create vitamin D using their skin. They need to get vitamin D3 from animal sources (not D2 from plant sources). Other vitamins and minerals cats must get from meat are vitamin B, calcium, phosphorus, iron, and vitamin A.