To answer this question we need to look at the difference between cat’s and dog’s dietary requirements. Unlike dogs, cats are obligate carnivores meaning that they have to eat meat to survive. Dogs, on the other hand, are omnivores, they need a varied diet of meat, grains, and vegetables in their diet. These grains and vegetables are not needed in a cat’s diet. The essential nutrients needed for cats are Taurine and Arginine, these are only found in meat.
Cats require more protein in their diets than dogs or even humans and have enzymes that are always set for high levels of protein. Cat food generally has around 30%-34% protein (more in tinned food) whereas dog food generally has 18%-26% protein.
If cats are fed dog food long-term various negative effects can occur. These can include a loss of muscle mass and lethargy. Taurine is essential for digestion, vision, heart function, and a healthy immune system in cats and is found in all commercial cat food.
Cats and dogs have different taste receptors with cats often being the pickier of the two animals. This is why cat food is engineered to be highly palatable for our feline friends. It is rather uncommon for cats to feel the need to eat dog food, whereas dogs tend to love the high protein content and flavor of cat food.
The other necessary ingredients that cats need to live healthy lives are Vitamin A, Arachidonic Acid, and Niacin.
Vitamin A cannot be synthesized by cats themselves and is generally supplemented in cat food. A lack of Vitamin A will result in a dull coat and muscle weakness.
Arachidonic acid is a fatty acid that can also not be created by cats. A low arachidonic- acid level will result in abnormal kidney and liver levels as well as increased skin issues. Dogs can create this acid by themselves, so it is rarely added to dog food.
Niacin (also known as Vitamin B3) is another necessary dietary requirement for cats. They cannot make Niacin themselves, so it is supplemented in their food. Niacin occurs naturally in meat and fish (as well as eggs and greens) and a deficiency in this nutrient can lead to loss of appetite, weight loss, and inflamed gums.
Now for the answer, technically cats can eat dog food in emergency cases or for short periods. Dog food is not dangerous to your cat’s health, it just isn’t recommended for long-term use. If your cat happens to get into some dog food, don’t stress over it.