When my large older dog who's a terrier breed was diagnosed with early signs of possible kidney issues and elevated protein levels showing in his urine, I knew it was the right time for me to consider making changes in the type of dog food I was currently feeding him. The question posed before me was which brand to choose as a substitute. My dog always had allergies to chicken including wheat and soy which is why I always in the past purchased a grain free dog food anyhow. Natural Balance fortunately still met those same requirements and it also doesn't irritate his stomach which is a common problem occurrence when you feed a senior pet. I especially like the fact that this formula is also lower in protein at 24% compared to his previous brand of dog food which was rated at 35% or even higher. Typically, anything going over 30% could be considered a high protein dog food. A level of 24% is only considered moderate and a considerable reduction even by my vet's strict standards. I've also read somewhere how sometimes giving your dog peas in their diet can also upset their stomach and I was happy to see that peas are not listed in the product ingredients anywhere. Finally, I needed to choose a dog food that has a lower level of phosphorus per serving to possibly help his kidney function and surprisingly many other brands don't even list the phosphorus level which for me was a bit concerning. That's why I'm so glad the the Limited Ingredients version sold here by Natural Balance has a phosphorus level of only .60 min. Very few brands if any out there in the marketplace appear to list phosphorus levels on their bags as being any lower. Trust me I cross- checked dozens of other major brands and I couldn't find any. Last of all, my dog really loves the taste of this Salmon formula and it doesn't leave him with a fishy breath smell afterwards like other brands sometimes have a tendency to do so. Some reviewers expressed concerns about their dog's stools being somewhat darker or even firmer. That's a typical characteristic of most grain free dog foods and my vet assured me that it wasn't anything I should be overly concerned about. This is the second bag here at Amazon that I've bought just recently and I highly recommend it. I couldn't be any happier and I wish all dogs Happy Tails and Bone Appetit.