If you read this blog regularly, you hopefully have at least some idea of the concept behind the paleo diet - eat the diet that we evolved eating over the last several million years, which didn't include rice, beans, grains, or starches (not until the last 10,000 years or so, a blink in evolutionary terms).
If you have a "furry friend" (cat or dog), take a good look at them. Note the fangs, and the claws, and the forward-facing eyes and (in most cases) ears? That is a predator species.
Now, take a look at the ingredients list on the food you provide for them. How many kinds of grain and starch are on the label? Do you think that they enjoy eating that, or do they just eat it because they're hungry and that's what's there?
All I'm trying to say is, if the paleo diet is good for us, then it's got to be good for our friends, too. So, when you're out picking up their food, show the same sort of care for the ingredients that you show when picking your own food out. It can be difficult, but it's not impossible to find grain-free pet foods. In my area, there are two different major labels that are sold as grain-free. One is called "B.G." (Before Grains), and the other is Wellness brand. We have a new kitten in our cave (part of the reason posting has been a bit sparser of late), and he's on a mix of the Wellness canned and dry foods for kittens, and thriving. And it makes me happy to know that he's eating what he evolved to eat - a high-protein meat-based diet. With any luck, he'll be around for a long time to come, amusing us with his antics.