I know when you feed a better grade food, they have less stool and don't tend to eat nearly as much.
A lot of foods out there are crap. The dog eats more and then goes to the bathroom more, because they're not becoming full.
I know my husband wanted to put Harley on Eukanuba, and I told him absolutely not. We don't have her on Nutro (we have her on Sensible Choice, which uses human grade chicken as it's first ingredient), but I know Nutro Natural Choice is a good food. They actually have a new product out called Nutro Ultra. I think that one is more of a holistic food.