The best diet for cats is a properly balanced, raw-food diet. But they can also stay healthy eating ordinary canned food. They shouldn't eat dry food, otherwise known as kibble, on a regular basis, because it causes health problems.
Cats are Carnivores
Cats in the wild are predators. They evolved to eat small birds and rodents, such as mice. While cats eat a mouthful of grass now and again, they don’t graze on plants as a source of calories and nutrients.
In nature, cats eat only 2-5% of their calories from carbohydrates, and that comes from the plants in their prey’s stomach.
Cats Need to Eat Meat to Stay Healthy
There are two ways that animals can get the proteins they need to repair their muscles and other bodily tissue: they can either eat the proteins whole, or build them inside their bodies. Unfortunately for cats, they don’t have the enzymes needed to make a complete protein from its building blocks. Instead, cats need to eat their protein whole, and that means eating meat.
When cats get their protein from plant food, it’s in an incomplete form and it passes straight through their bodies unused. This is unfortunate for cats fed on dry food, considering that kibble is made largely from plants, such as grains and potatoes. Even though the dry food contains the right percentage of protein, it still leaves your cat lacking in essential nutrients.
Raw food diets, on the other hand, are 100% meat and bone. While most canned foods contain a high proportion of meat compared to dry foods. Eating one of these ensures that your cat gets enough complete proteins.
A Meat Based Diet for Cats Prevents Obesity
Because plant based, dry food doesn't nourish your cat properly, your cat feels unsatisfied shortly after its meal. Its natural reaction is to try to eat more food, so it can get the nutrients it needs. If the only food available is more kibble, your cat can never feel properly sated, and the vicious cycle continues.
A well-balanced raw food diet is the best diet for cats though, because it gives your cat all the nutrients it needs. This leaves your cat feeling satisfied after its meal, and the urge to overeat disappears. Canned foods also do well in this regard, because of their generally high meat content.
Dry Food Dehydrates Cats
In nature, cats get all their water from food, and only drink in emergencies.
Because they rely on food for their water, they get hungry when they start to dehydrate, not thirsty. This means that they ignore their water bowls, and only drink from them when they’re truly desperate. Even then, cats only drink enough to tide them over until the next meal, not enough to properly rehydrate themselves.
Unfortunately, if their next meal is kibble, the cats stay dehydrated, since the average kibble contains 8% water, while your cat’s natural prey is 65-70% water.
If your cat does walk around dehydrated, it can lead to painful and dangerous medical conditions, such as urinary tract blockages or cystitis (bladder infection.)
The fresh meat in a raw food diet contains as much water as your cat’s natural prey, however, and canned food contains an average of 75% water. This is more than enough to keep your cat well hydrated, so that it doesn't become unwell.
A Meat Based Diet Protects Cats against Gum Disease
The carbohydrates in kibble start breaking down into sugars as soon as they enter your cat’s mouth. These coat the teeth, causing a build up of tartar, and eventually gum disease.
When cats eat meat and bones, however, the process of chewing and grinding the food cleans and polishes their teeth. This keeps the teeth free from tartar, and prevents tooth loss.