Link between sugar and behavior?

So I have always heard people joke about giving kids sugar and their behavior, but does anyone have any links to documentation on this?

I swear, it turns DS into a wretched little human being. Today I gave him half of a peanut-butter/choco rice krispie thing my mom made and he went into full tantrum mode within 10 minutes. He is now wearing only a diaper in his crib and huffing and puffing in there. I know he's not tired because he had just gotten up from a good nap. Maybe it has to do with having it within 30 minutes of waking up? 

When he was younger he went through a time where he would have night terrors if we let him have a sweet after dinner (b-day cake, etc.).

I am just wondering if he  is someone who should not have sweets period. We don't give him much sugary stuff beyond fruit and the treats named above (special occasions).

I know several of you are pretty well-versed in behavioral and dietary issues, so I thought I would ask here, rather than on his age board.