well, I really don't know. My mom also always fed our cats cat chow or something similar, as well as all our dogs, and they never had problems, except are all getting old. BUT, I think the difference for me is that our babies started on the higher brand stuff, and I am weary about changing them to a cheaper brand. I don't really care what we feed them, but don't like to change them around. I don't want them to start getting sick. The only cat we had to feed expensive food was our one indoor cat, the rest were all outdoors. We have not had an ounce of health issues other than old age with any of our pets. So I have no thought that one kind is actually better (unless problems arise like being overweight). I just don't want to keep changing them when they have been used to one brand for almost a year, and Pip has had his food for four months. I AM SO CONFUSED!