Is sugary high a myth?
As father of a two year old, I have to listen to ridiculous parenting superstitions. "He's hyper, did you give him any sugar?" No, but if I had would that be evidence that a lack of sugar causes hyperactivity?
Sleep is the ultimate throwaway explanation. Sleep is the explanation for his energy whether he got a lot of sleep or very little. If he got a lot of sleep then that just gave him all the energy in the world. If he didn't get much sleep, then that's why he's so loopy and silly; he's trying to keep himself awake.
So I'm not surprised to find plenty of evidence that sugar highs are a myth.