Life's Little Mysteries

Does sugar make kids hyper?

If a child eats cotton candy, a chocolate bar or any other kind of sugary treat, will a hyperactive frenzy follow? While some parents may swear that the answer is "yes," research shows that it's just not true.

Yes, that's right. "Sugar does not appear to affect behavior in children," said Dr. Mark Wolraich, chief of Developmental and Behavioral Pediatrics at Oklahoma University Health Sciences Center, who researched sugar's effect on children in the 1990s.

Instead, parent's expectations of so-called "sugar highs" appear to color the way they view their children's behavior, Wolraich said. It's easy to see why parents make the link: Sugar is often the main attraction at birthday parties, on Halloween and other occasions when children are likely to bounce off the walls. But all that energy is due to kids being excited, not from the sugar in their systems, he said. 

Related: Why does mint make your mouth feel cool?

If parents believe that sugar affects their children's behavior, "their ideas are reinforced by seeing it in those circumstances," Wolraich told Live Science.

The misconception comes from the idea that increased blood sugar levels translate into hyperactive behavior. It's true that someone with low blood-sugar levels (known as having hypoglycemia) can get an energy boost from drinking a sugar-filled drink. But it's a different story if someone has a sugary treat when he or she doesn't have low blood sugar.

"The body will normally regulate those sugars. If it needs it, it will use the energy," Wolraich said. "If it doesn't need it, it will convert it to fat for storage."

That's right — if you have a donut when your blood sugar level is already just fine, those extra sugars may be converted into fat.

Sugar high?

Much of this information comes from studies that Wolraich and other researchers did in the 1990s.

For instance, the researchers found that mothers rated their sons as more hyperactive when told that the boys had ingested sugar, even when the children hadn't done so, according to a 1994 study in the Journal of Abnormal Child Psychology. In the study, 35 boys ages 5 to 7 were given a drink containing an artificial sweetener called aspartame, which is not made of sugar, but rather of amino acids. Half of the mothers were told that their boys had received sugar.

When the researchers asked the moms about their sons' behavior, the women who were told their sons were given sugar rated their children as more hyperactive, the study found.

Moreover, the researchers also videotaped the interactions between the boys and their moms. The tapes revealed that the mothers who believed their sons had sugar stayed closer to their sons and were more likely to criticize, look at and talk to their sons than the mothers who were not told their sons had been given sugar.

"The placebo effect can be very powerful," Wolraich, who was not involved with the study, said to explain the results.

However, this study (and many others) looked only at sugar consumption at one point in time. So, Wolraich and his colleagues decided to do a longer, nine-week study. However, they still failed to find a link between sugar and hyperactivity, he said. 

Related: Typical toddler behavior, or ADHD? 10 ways to tell

In that 1994 study, published in the New England Journal of Medicine, researchers examined children whose parents thought they were sensitive to sugar. In all, the scientists looked at 25 preschool children, ages 3 to 5, and 23 school-age children, ages 6 to 10. Each family followed a set diet for three weeks at a time: One diet was high in sugar (sucrose), another was high in aspartame, and one was high in saccharin (a noncaloric sweetener).

The study was also double-blind, meaning that neither the families nor the scientists knew which child was on which diet at any given time.

According to cognitive and behavior tests, as well as reports from parents, teachers and researchers, "there were no significant differences among the three diets," indicating that sugar did not effect the children's intellect or behavior, the researchers wrote in the study.

Furthermore, Wolraich and colleagues published a review in 1995 in the journal JAMA that included 16 studies looking at the "sugar high" issue. This review also "found that sugar does not affect the behavior or cognitive performance of children," the researchers wrote in the study.

In fact, the statistician who worked on the 1995 paper, in which the researchers statistically combined the results from all of the studies done until then, said that, "he had never had such consistently negative results." This means that sugar consistently failed to create the fabled "sugar high," Wolraich said.

Originally published on Live Science.

Laura Geggel

Laura is the archaeology and Life's Little Mysteries editor at Live Science. She also reports on general science, including paleontology. Her work has appeared in The New York Times, Scholastic, Popular Science and Spectrum, a site on autism research. She has won multiple awards from the Society of Professional Journalists and the Washington Newspaper Publishers Association for her reporting at a weekly newspaper near Seattle. Laura holds a bachelor's degree in English literature and psychology from Washington University in St. Louis and a master's degree in science writing from NYU.