i'm not sure it's actually a "natural fad" - i saw a news brief on the local NBC channel here and i did more research into what i learned - the non-natural foods have a lot of really bad things in them. the news said that there are dead, dying, diseased animals in the pet food (animals not fit for human consumption). there were also traces of penobarbital in the pet foods (from euthanized animals), traces of flea collars, traces of the styrofoam from the meat from supermarkets past its "sell by" date...there are a LOT of terrible things, and if they're not good for our bodies, they certainly aren't good for our kitties' bodies.
so, you may want to do a bit of research. i was shocked to learn what i'm putting in my little darlings' bodies. i've switched to wellness brand (a natural food with only human-grade ingredients) - before making my decision, i looked into innova, natural balance, natural choice, felidae, royal canin and flint river ranch. those are the best on the market - and they aren't more expensive than the science diet that my girls were on before - just better for them!