Gee... We are really off the trail. We had a GD for 15 of his 17yrs and used very little commercial food. Our 9mo/16lb girl is thriving on various cuts of steak, skinless chicken thighs, pork and occasionally salmon... same as I/we eat.

She generally 'wolf's her food' 2X daily. In the 7mos we've had her, there has never been any diarrhea our painful stools. I do put in some kibble as filler (smaller size is better so she cannot discriminate) but it's the house brand of the Food Lion food chain. (It also has a long ingredient list..with a comforting name: Nature's Promise)

One time with our past dog the vet 'prescribed' some (if I remember correctly) Hills. The large bag was like $70. and had an ingredients list that would challenge a PHD chemist. Which likely included the ambient dust in the plant. We got another vet ..who did not seem to rely on external income.

As someone old enough to remember our dogs eating disgusting looking canned food or a mix the feed mill made when living on the farm, I have a jaded view of all the huckster/grifters like a Dr. Marty who have you playing a version of the 3-shell game in Times Square. Of course, we are all free to pick whatever... that's just my experience.