Myth: Sugar makes kids hyper.

Fact: Many studies have shown that consuming large amounts of sugar does not inherently make kids (or adults) bounce off the walls. But that doesn't mean your kids won't go crazy after eating handfuls of Halloween candy or a slice of birthday cake.

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 Journal of the American Medical Association published a review of 23 studies on the subject, and the results back up Robinson's rationale.

One study included in the review divided 30 boys, ages 5 to 7, and their mothers into two groups. Researchers told one group of mothers that their sons had consumed a drink with high sugar content. They told the other group of mothers their sons had a sugar-free drink. In truth, all the boys had sugar-free drinks. But the mothers who believed their sons had consumed sugar reported higher levels of hyperactive behavior. (Source:

Another study showed that when kids ate sugary snacks that they and their parents believed to be sugar-free, they did not report behavior changes.

When healthy people consume sugar, there is a small and temporary increase in their blood glucose levels. But Robinson says many people wrongly believe higher glucose levels make them feel more energetic. In reality, healthy people can't feel the effects of these relatively small blood sugar increases at all. And people with medical conditions such as diabetes, which prevent them from processing sugar, actually feel more lethargic when their blood sugar levels are very high.

Even if trick-or-treats don't turn kids into mini-monsters, Robinson recommends that parents limit candy for many other health reasons, from dental health to weight control.