Food Ingredients

I have had both cats on Nature's Variety Lamb and Oatmeal recently, but since one is being switched to a prescription diet and they can't share anymore I want to put the other back on a grain-free food. He wasn't doing very well on EVO since the recipe change, so I need something different. I was looking at the Nature's Variety Instinct, but there are a few ingredients that I am questioning. Tapioca is one. I thought that would be considered a grain. Another is Montmorillonite Clay. I can't figure out why they would include this in food, and whether this is a good thing or a bad thing.

Also, what are your overall opinions of Nature's Variety Instinct?

clay is something that absorb s... help with diarrea and also supposedly acts as a detox ...

Overall I find it complicated ie lots of ??? ables as to need but it is a very high quality food ( I have read some ???s on that but then again name a food without ANY complaints )

Tapioca is KNOWN as one of the few things HUMANS arent allergic too