I can add I do as Tracy does. High quality grain free food. Small poops, the pudgy cats slimmed down (except for Crystal, lol), they are healthy and coats are shiny.

You can find some info about cat foods here:
http://www.petfoodratings.net/cattable.html

I fed Taste of the Wild for several years. That became unavailable for a time as of April of this year and I switched to Earthborn Holistics - they offer grain free formulas as well.