My dog was a picky eater. She, sometimes, refused to eat for a couple of days. We were always changing brands and trying to add something to her food to make it more tasty. But after starting giving her dog chef, she turned into a completely different dog!
It's a noticeable change, as now she eats everything right after putting her food in the bowl. I even have the impression she is more energetic than before (probably because she would eat enough before).