Gosh, I cannot tell you exactly how many different foods I have tried with Harley. When I adopted him they were feeding him Beneful, yuck! We stuck with that for his first month because that is what he came with and he had been to a total of 3 places in a months time.
After that I tried Purina One, the Purina Pro Plan, Authority, Avoderm, Timberwolf, Solid Gold, and now Wellness. All the prior foods Harley would nibble ate and graze all day. I did see some improvements with Timberwolf and Solid Gold. On Solid Gold his energy level was lower then on Timberwolf.
He just didn't seem to care too much for any of the foods. I went to the feed store and bought Wellness and he absolutely loves it and eats it all. I have seen a huge improvement in his coat and he now has more energy. He seems so much happier and more active. He has more spunk lol.
Right now he is snoring next to the computer as I type after a good long session of fetch.
For those out there struggling to find the right food I say keep trying and you will suceed. It has taken me almost 2 years!