It's not the protein levels but the calcium levels that make it not the best choice for a growing giant puppy. The dog nutritionist I talked to about feeding it to my english mastiff puppy since I already feed it to my other two said Sierra Mountain was the only one with a low enough calcium level to make it okay for giant pups. There are certainly plenty of other choices but Taste of the Wild is a good, middle of the road price wise food. I agree though that asking a vet is definitely not always your best bet. Most vets received minimal education about nutrition, which is understandable considering all they have to learn.
What is considered a good calcium level for giant breed pups ? I will have to double check the %'s , but im pretty sure the TOTW was fairly close to the Performatrin puppy food we were feeding her.