I admit that I am a dog food snob for my dogs, but I know dogs that lived long and healthy lives on crap like Gaines burger - that was the plasticky imitation hamberger patties. That said, I don't know how well they really felt on the inside. I, personally, have a terrible diet, but I look healthy and feel fine. When I do make an effort and go on a health kick and eat better, I do feel much better.
I always recommend a dog be fed the highest quality dog food that the dog does well on and that the owner can find and afford, but knowing how well some dogs do on very poor diets, I don't look down on people that do the best they can on lower quality diets.
Elaine and the herd