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The Truth About Kids Getting ‘Hyped Up’ on Sugar

It’s not the candy — it’s the confirmation bias

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It’s nearly the scariest night of the year—that terrible evening where good, hardworking folks are terrorized by tiny children who are after only one thing: human flesh.

Sorry, I mean candy. They’re after candy.

The science shows pretty conclusively that sugar itself doesn’t make children hyperactive.

On Halloween, we engage in a wonderful ritual. First, children dress up and parents everywhere call them adorable and cute. Then, they go around the neighborhood trick-or-treating, and similar parents pay them in sweets and call them adorable and cute all over again. Finally, the children come home, gorge themselves on their sweet hoard, and go wild with all that sugar. Every parent knows this.

Except, the evidence doesn’t stack up. The science shows pretty conclusively that sugar itself doesn’t make children hyperactive.

The grand urban myth is just that: a myth.

The sugar hypothesis is fairly simple: We burn sugar for energy. Eating a lot of simple sugars means that you process them very quickly and, thus, should have a big spike of energy — which in kids can be exhibited as hyperactivity. This is backed up by a lot of anecdotal evidence from parents who see their children go to parties with tons of sugar and come back excited and pumped.

If your kid is hyperactive, it was obviously the sugar, right?

Well, that’s why there’s science. We have a plausible hypothesis: Sugar causes hyperactivity. But scientists were interested in knowing exactly what was happening. Was it the sugar or could there be some other explanation for these anecdotes?

In the ’90s, a series of experiments were conducted to address this exact question. In the most famous of these, mothers were told their children had either been given sugar or an artificial sweetener. They were then each asked to rate their child’s hyperactivity. Despite all the kids only eating artificial sweeteners, mothers who’d been told their progeny had eaten sugar were more likely to rate them as hyperactive.

It seemed sugar was not actually causing the kids to be hyperactive. Rather, these mothers’ expectations—everyone knows that sugar makes kids antsy—was making them believe their children were hyperactive, even if they weren’t.

Sugar, it appeared, was not to blame.

Sugary treats are pretty terrible for children regardless.

Further studies have confirmed this. In fact, the exact opposite seems to be true: Eating sugar makes people—both children and adults—more alert, less aggressive, and more in control. All of these findings are based on fairly weak evidence, so take them with a grain of salt. But they do make the sugar-equals-hyperactivity hypothesis less likely than most parents would like to think.

It turns out that the most plausible explanations are social. Everyone knows (or thinks they know) that sugar makes kids hyperactive, so when we see kids who are hyperactive, we assume they’ve eaten sugar. When kids eat sugar, we assume they’ll be hyperactive. It’s a vicious cycle of confirmation bias. But when you actually test this idea in a scientific experiment, you find that sugar doesn’t even cause hyperactivity in children with diagnosed ADHD.

What does this mean for the stickiest night of the year? Honestly, not that much.

Sugary treats are pretty terrible for children regardless of whether they make them hyperactive or not, but a single night of gluttony is probably not the biggest issue. We know that eating large quantities of heavily processed foods high in sugar day in and day out is not great for growing bodies, but the impact of Halloween is much smaller than, say, whether a child has ready access to soft drinks year-round.

In general, both adults and children should limit their intake of sugary treats — but not because they make us hyperactive. Candy has numerous problematic health effects, which is not surprising given that most of it is pure calories and not much else. Nonetheless, kids we believe to be “hyped up on sugar” are probably just reacting to our own expectations of what kids do when they gorge on sweet deliciousness.

Bottom line? Don’t worry about hyperactivity. Your kid is fine. They’re probably calmer than you think.

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