I feed Now!
http://www.petcurean.com/index.php?page_id=161
It was hard to find a lower protein, super-premium dog food. My vet told us to get off of the Wellness Core we were feeding, because he is a believer in the fact that too high a protein affects the liver, and indeed my dobes liver tests were elevated before she had surgery last fall.
My dobe will be considered a senior (7), and my GSD tends to just be too plump, so we chose the senior/weight management variety.
They get it mixed with a small amount of Deli-fresh dog food, and warm water.
A good link for things to avoid in dog food, and all kinds of other good information:
http://www.dogfoodproject.com/index....badingredients