It is also seems to be a remarkably American belief. The first time I came across it, was in an American book (at the age of 20 or so.) Having grown up mostly in Europe, I had never heard about this before then, and my first thought about it, thinking back to my own experiences with sugar and hyperactivity was "that... sounds like bullshit."

However, I’d let the kids brush their teeth after the evening sugar treat. Sugars' relation with Karies seems to be of a more causative kind.