I can't speak to the actual statistic's regarding feeding grain free food's, natural food's, more expensive brand's of food compared to "ol Roy" or "Skippy" dog food BUT I rationalize it this way....with us always having more than one rescue(we have 4 at this time) and Vet bill's the way they are(No offense Dr. Doug) I figure it can't hurt to feed a "so called" quality food in hopes that it does benefit a dog's life or life span? I'm sure there must be studies regarding illness'es in Pet's in relationship to what they are eating as a diet? and since illness equates to Cost(Vet cost), it seems there should be some data one way or another?
As you can see, those are questions.....just thinking out loud.