why not corn?

My cats will eat corn in its natural state.
But not potatoes, rice, or those other ingredients.
My Lucky is good for at least three kernels of popcorn.

Depends  upon whom you talk to.

Many cat owners trust in feline nutrition experts such as Dr. Lisa Pierson, who is absolutely against providing foods with substantial corn, wheat and soy content to cats.  On this board there are posters who have said, based on their experience working in a vet office or working for a pet food company, that in most cases corn is not unhealthy for cats.  There are even photos of cats hilariously eating corn on the cob.  That wouldn't be my choice for my cat's menu but to each his own.

Clearly, some commercial foods are better than others.  When my gal was a young kitten I gave her a recipe that included corn as a principal ingredient, but not the primary ingredient.  I avoid corn nowadays.  Excessive carbohydrate intake leads to obesity in humans and cats!

Cats are obligate carnivores. They have no biological need for corn or other vegetables. They need to be on a diet that is high protein and low carbohydrate. Corn, potatoes, peas and such are often used in some cat foods as fillers to keep costs down but they do not need it and thus, their bodies do not utilize these things. I noticed that the fewer fillers and unnecessary foods my cats eat, the less waste they produce and the smell is negligible.  When I first got them, all 3 were on lower quality foods from shelters and the smell from the litter box could knock a buzzard unconscious or make a skunk seem like a walking rose garden. 

I personally wouldn't feed them corn. if you're looking for a snack that is closer to what they need biologically, my go to is Pure Bites freeze dried chicken breast treats. They are chicken breast and nothing else. I get the big dog sized bag from Amazon. I also give them roasted chicken breast from time to time and they love Boar's Head low sodium chicken and turkey which are minimally processed. 

Cats can eat plain pumpkin puree (not pie filling) if you are looking for a veggie to give them. Plain pumpkin is a good way to keep the digestive system running normally as it is a good source of natural fiber and it helps regulate water in the colon. It is good for diarrhea and constipation if either issue arises. Most cats like the taste too. Just make sure the ingredients list does not mention anything other than pumpkin. 

Kat0121 is  right about seeing the benefits of better quality food when it comes to your cat's litter box,  My rescue cat was feed the cheap stuff at the shelter and for the first several days at my home you could tell the lack of quality from her stools.  Giving her some of the better recipes from Fancy Feast, Evolve, Purina Beyond etc.  has eliminated the gag-inducing odor from the litter box.

I was questioning the pet food makers. That they maybe exaggerating the problem. The most expensive food isn't much better than the cheap stuff. Just the place where you buy it.

Can food is better than dry