Well, as i see it, he is only doing research, and as such he will just read the same statement elsewhere.
Proteins are broken down into carbs when there is no fat left in the body at all, so if u live on egg white for a week, the body will burn fat off first.
Protein is inefficent to metabolise, and so is not the bodies preferred method of repsiration.
However protien contains C H and O and therefore can be used to be broken down into ATP at some stage.