I whole-heartedly agree that too much protein is a bad thing... the important question is how much is too much, and how much is too little? Some might argue that a raw diet is all protein - it isn't. Much of it is moisture, fat, bone, etc.

However, I disagree, that there is no difference between plant protein and animal protein, to an opportunistic carnivore (NOT an omnivore).

When starches are broken down, they must first be broken into sugars in order to be usable. Dogs and cats do not normally produce enzymes in their saliva to actually break-down carbohydrates and starches. Amylase in saliva is something omnivorous and herbivorous animals possess, but not carnivorous animals. Their pancreas is forced to produce large amounts of this enzyme to deal with the starches. Dogs also do not have the kinds of good bacteria that break down cellulose and starch for them.

Ideally, a dog can only digest about 50% of a grain-based food. That is why manufacturers of these food have to add a plethora of extra vitamins and minerals, to compensate. So the question then becomes... would you rather your dogs get their necessary nutrients from additives, vitamins, and only partially digestible matter; or from a natural, biologically appropriate source?

Don't write off everything you've learned about nutrition, from one single lecture... take it with a grain of salt, and continue researching independently (reliable sources, of course). That's what I think, anyway. : )