I have fed my cats the raw diet for many years and they have always been well, then my spouse died and I stopped making this food as it was a bit of work for me to do by myself and I had so much responsibility with a sick person. The result is several months later one of my cats developed some serious problems and was not absorbing nutrients, losing weight etc.
I went back to making the raw food and is he now back to his normal weight and well again. I make a large amount, and freeze in small plastic containers, thaw as needed. The commercial food for cats is terrible stuff. These cats are carnivores and by feeding them commercial food (especially dry), we feed them totally inappropriate food for their species. We need to give animals the closest thing to what they would eat in the wild. Same for dogs.