All good points Keith and something that I think about often: my son Joshua turns 18 on the 23rd of this month

His Mom and I have been apart for the last 16 years and during all that time he has spent alternate weeks between his two homes... I am
not restricting him to eating the same way as I do, so what do I feed him..?
In my humble opinion the discussion here too quickly becomes polarised to extremes of low "this" or high "that" when -- as been wisely pointed out before -- the same amount that one person counts as "low" another may count as "high".
From my personal viewpoint I am an obese middle-aged man with Type 2 who has found out through experiment that I currently have a very low-tolerance for most, if not all carbs. I believe that my body's ability to manage sugar has been overwhelmed by too many years of too much fast-acting sugar. It is possible that as my weight and insulin sensitivity improve I may be able to allow myself more flexibility in my diet.
I don't want Josh to end up the same way, and I am hopeful that there is still time to set him on a healthier path. It may well be -- and I am leaning this way -- that all he needs to do is watch the "bad carbs" such as High Fructose Corn Syrup; by eating predominantly "real", whole, unprocessed foods.