He's old enough now to have more control over the effects. Before he's given something sugar-laden, he's reminded that it's not an excuse to act up...it's an opportunity to show me he can control the effects of sugar so that he's more likely to be allowed a treat next time it's offered.
It's great that your ds can recognize the "sugar effect". Too many kids (and parents) don't see it.
I don't want to ban all sugar laden treats; I just want people to notice when they cause problems for kids. The problems can be managed.