Hello, being in the med profession myself, I thought I'd jump onboard and give my 2 cents.
First off, from what you say, I think your child is getting plenty of carbs (beans, bread, pizza, oatmeal, cereal, etc.). It's really not so much about the AMOUNT of carbs as it is about the KIND of carbs your child gets that will determine his health.
Furthermore, I wonder how recent and how far back your ped's education covers, because the current food pyramid is actually an alteration of the original one. The current one states that we need a lot of carbs because that's the base for our nutrition... well we don't, because it's not. The REAL base for our nutrition starts with the plant groups - fruits and vegetables, then meat and dairy, then grain (carbs), then sugars and fats.
Also, not all people and their bodies are alike, your child's nutritional typing may require more emphasis on protein, or be combination, rather than carb-oriented.
So don't worry about it, just make sure he gets the right stuff and you and he will do great. :)
And I'm with you about the disorder thing. We seem to live in an age where every little thing indicates a disorder. It's like every measley deviant behavior or quirk has to be diagnosed and analyzed, or means that there MUST be something medically and/or psychologically not right with the child.
Bollocks!
Some people just can't accept the fact that their kid is just plain naughty, or defiant, or stubborn, or lazy, or strange in some way. Just because they aren't your perfect paper-doll cut-out child doesn't mean you need to diagnose and drug them to death!
Some of my colleagues would take umbrage with my little rant here, but don't be fooled, not all doctors or med profs truly have your best interests at heart. In my career I've seen far more than my fair share of those who got into the field just for the large sums of money they can make, not for the service to the public good. They make me sick at heart and I try not to associate with them if I can help it. They also tend to not bother with education beyond what they got in college and whatever's new, fashionable, and/or profittable. :P