Factors that can contribute to disobedience and aggressive behavior include boredom, lack of stimulation, an inadequate diet (especially one with too much protein), allergies, stress, lack of attention and/or lack of exercise.
As far as the article goes it was, meh, but I do have a question about this first part.
Have any of you heard why a food high in protein would cause behavioral/disobedience problems? I've never heard of that, and I'm not convinced of the validity of that statement. You all know much more about the foods than I do, so I would be interested to hear your input!