Does sugar make children hyperactive? To the surprise of many, particularly parents gearing up for tonight's Halloween craziness, the answer is no.

A large body of scientific evidence debunks the notion of a cause-and-effect relationship between sugar consumption and children's hyperactivity. So what's actually going on? The San Francisco Chronicle interviewed a Stanford nutrition expert today to find out:

Dr. Tom Robinson, director of the Center for Healthy Weight Lucile Packard Children's Hospital at Stanford, explains that because so many parents (and thus children) expect eating sweets to make them hyper, it becomes a self-fulfilling prophecy. "The way we think we should feel has a lot to do with how we do feel," he said.

The story mentions one of my favorite studies on the subject, in which parents who thought their kids were sugar-sensitive were asked to rate their child's behavior after the children had consumed soda. Parents who heard that their children received sugar-sweetened sodas rated the youngsters' behavior significantly worse than those who were told their kids drank artificially-sweetened soda. The catch? All the kids in the study consumed artificially-sweetened sodas.

Several other studies have attacked this question from different angles and reached the same conclusion that eating sugar doesn't make children hyperactive. But as Robinson notes in the Chronicle piece, there are plenty of other good reasons, besides hyperactivity, to limit children's sugar consumption. Two such reasons are sugar's connections to promoting obesity and dental cavities.

In total, the hyperactivity research provides a perfect example why it's important to tease apart correlation from cause-and-effect in scientific research. The fact that sugar consumption and hyperactive behavior often occur together (i.e. are correlated) does not mean one causes the other. So when your kids are jumping around like maniacs tonight, don't blame the candy. Instead, the excitement of dressing up, heading out into the dark, yelling "trick or treat!" or, perhaps, their loving parents tell them "All that sugar is going to make you crazy!" could explain the phenomenon.

Previously: Examining why instilling healthy eating and exercise habits in children may not prevent obesity later in life; In animal study, high-fructose diet compromises cognitive function; How eating motivated by pleasure affects the brain's reward system and may fuel obesity

Photo by jamalfanaian