Finally I'm vindicated! The Straight Dope tackles my biggest social pet peeve! There is no such thing as a Sugar Rush or Sugar High. It doesn't exist, so stop perpetuating the myth!
This particular issue is a personal annoyance simply because of the sheer pervasiveness of the myth. On average, I hear somebody mention this myth at least once a day. It's usually on television, but also quite often in the real world.
So please just stop it. Ingesting sugar does not change your behavior or give you a "rush" of any kind... except for the placebo effect generated from all your years of brainwashing and ignorance.
I don't think I've ever had plain sugar, so can't comment specifically on whether or not it creates an artificial high.
I do believe that the food you eat or drink can have an effect on your body, mood, or mental state. I think I live that every day.
I remember one day in college where I ate a whole bag of jolly ranchers. I was definitely a bit loopy in the evening. I have no idea what is in a Jolly Rancher, but I was definitely effected by something.