I read somewhere that there’s no evidence that sugar actually makes them hyper. It cheers them up and excites them, but then so do lots of exciting and nice things.
I heard/watched/read the same, think there was an experiment on TV with a bunch of kids fed with sugar loaded snacks and another fed on normal foods. The parents weren’t informed which was which and the results indicated no conclusive evidence, except the parents claiming to notice their kids loaded when they weren’t!
if you want to wind ’em up a treat the only way is amphetamines, though that does raise a whole load of ethical/moral questions, not to mention the legal position…