Why is organic cat food harder to digest?

Your cats may be so used to the fancy feast that when offered new food they weren't sure what to think? My cat threw up once after trying a new food too. I think it was because it was something so different than what their stomach are used to the fancy feast. You could mix the two together and slowly remove more and more of the fancy feast. I've been feeding my cats true buffalo blue brand and actually have duck, chicken and salmon. I keep rotating every meal with a different flavor to keep it interesting! Try mixing them together. I don't give my cats any food or treats with by products. I think they eat better than me!