Bio-appropriate is one of the latest buzz words in the pet food industry. It is used to categorise foods or ingredients that are appropriate to the animal - that is foods that the animal is evolutionarily adapted to consume, digest and utilise. For most (but not all) canine nutritionists, this means comparing foods with the diet of the wolf since wolves are the closest wild relatives of domesticated dogs. The closer a food is to that eaten by a wolf, the more bio-appropriate and therefore the better it is.
A typical bio-appropriate food would be high in meat (usually 50-80%), would contain a variety of vegetables, fruits and herbs and would be completely grain free. Relatively modern ingredients like soya, dairy and, of course, artificial additives, are strictly avoided. Many bio-appropriate advocates also adhere strongly to raw feeding principles.
It should be noted that not all canine nutritionists would define bio-appropriate in this way. The principles above are based on the theory that dogs are physiologically unchanged from their wolf ancestors but some nutritionists believe that the 30,000 or so years of their domestication has left modern dogs much less dependent on meat, far better at digesting grains and more suited to cooked foods than their wild counterparts. The debate continues.