I feed Purina pro plan sport active 27/17 all ages food. I have tried other brands but I came back to Purina. I figure they have been making dog food for a long time so they know what they are doing. I have two boxers and their coats have never looked better. They like the food and the 37.5 pound bags work out just about perfect for a month of food for the two of them. One of them is seven years old and the other is three but you can't tell yet by the way they act. Very Active! And this food is all they eat other than the occasional table scrap they beg.