I am sorry I cannot remember how it was exactly explained to me by a nutritionist. But apparently Innova has almost all USABLE protein which is somewhat different in the way it is processed in the body. Excess protein goes thru the renal system and just gets peed out so it stands to reason that it would be hard on the renal system as it is working harder. BUT usable protein I am just not able to remember what he said about it

I would go to the Innova website and read up. I chose not to feed it because of the high protein, I supplement my dogs food too much as it is.