Question about corn

I know grain based cat foods are not good for cats. Corn is often mentioned as an evil. I'm trying to get a better understanding of why corn is worse for cats than other grains such as brown rice. Does anyone have any information on that other than the fact that some cats are allergic to it? Just wondering. I want to be more knowledgeable about this.

I'm NOT an expert, I have been doing lots of posting to find out about foods (part of two threads today), but one thing I picked up is that its just filler. It does them no good, just goes right through them. Also as you said, its a big one for allergies (my dog has wheat/corn allergies). I'm sure someone who knows a lot more than me will answer better soon!

Corn is not at all digestible, not even by omnivores like humans and dogs.

rice is acceceted as the most digestable grain ( white rice the br is high fiber thus lowers digestability)

corn is a huge allergan in many animals .... it is also not so digestable ...
corn gluten can be used in some corn allergic cats and is a protein ..

The easiest way to look at it is - what would your cat eat in the wild?

Corn is not a huge part of their diet in the wild and so is best not to be in their diet. Corn is generally used as a filler and does not include any of the vitamins and minerals - taurine etc - that cats need. However, for most major pet food manufacturers, matching a cats wild diet is expensive and therefore not practical.

Here is a great article about catfood and its ingredients - sorry if this has been posted before (PLEASE NOTE: PDF format)