The boys got no sugar at all. But some of their mothers were told they had, and those mothers were sure they could tell.
That’s the setup of one of the most famous experiments on a belief almost every parent holds on Halloween: that candy turns kids into tiny tornadoes. The science on this one is surprisingly clear, and it’s not what the folk wisdom says. Let’s walk through the experiments in the order they happened.
Experiment One: The Mothers Who Were Told Sugar
In the early 1990s, psychologists Richard Milich and Daniel Hoover studied 31 boys, ages 5 to 7, whose parents described them as “sugar sensitive.” As Popular Science describes it, every boy was given a drink sweetened with aspartame, not sugar. Half the mothers were told their sons had just had sugar. The other half were told the truth.
The result was striking. Mothers who believed their sons were on a sugar high rated them as more hyperactive, and they criticized them more harshly, even though no sugar was involved. The researchers concluded that the link between sugar and behavior might come from parents’ expectations, not the sweetener.
Experiment Two: The Double-Blind Diet
Pediatrician Mark Wolraich, now at the University of Oklahoma Health Sciences Center, ran a different kind of test. In a double-blind study, children were fed different diets, one high in sugar, others using artificial sweeteners, and neither the families nor the scientists knew which child was on which diet at any given time. As Live Science notes, the results didn’t show sugar changing behavior.
That matters because it removes the guesswork. When nobody knows who got sugar, expectation can’t leak in.
Experiment Three: Combine Everything
The strongest evidence comes from combining many studies at once. In 1995, Wolraich and colleagues published a meta-analysis in JAMA that pulled together 23 experiments reported across 16 papers. Their conclusion was that sugar, mostly sucrose, does not affect the behavior or cognitive performance of children.
The researchers did add a caveat. They couldn’t rule out a very small effect in some children, and they called for bigger studies. But as Medical News Today summarizes it, whatever effect might exist isn’t anywhere near as large as many parents report.
So Why Does It Look So Real?
If the science is this clear, why does the myth feel so true? A few reasons stack up.
Think about where kids eat sugar. Halloween, birthday parties, and holidays come with costumes, friends, noise, late bedtimes, and a break from routine. Wolraich told Live Science that the energy at these events is better explained by kids being excited than by what’s in their bloodstream. Add in what Experiment One showed: when you expect a sugar rush, you notice behavior that fits.
There’s also a simple story problem. “Sugar did it” is a tidy explanation. “Seven excited kids, a skipped nap, and a room full of costumes” is messier.
What We Can’t Say
It’s worth being careful about the limits. Most of the strongest studies tested short-term effects on behavior, such as what happens in the hours after a sweet snack. Longer-term eating patterns are a different question. A 2019 review in the Journal of Affective Disorders, discussed by Medical News Today, found that a diet high in refined sugar and saturated fat was associated with a higher risk of ADHD. That’s an association over time, not the same as a sudden sugar high, and it doesn’t show sugar is the cause.
And none of this means sugar is harmless. Too much of it is still bad for teeth, and heavy intake over time is linked to weight gain and other health problems. The myth is about behavior, not nutrition.
What to Do With This on Saturday
You don’t need to ration candy out of fear of a meltdown. If your kids are bouncing off the walls on Halloween night, there’s a much better suspect than the candy bowl: the excitement, the costumes, the friends, and the late night. Let them enjoy it, keep an eye on teeth and stomachs, and plan for a good night’s sleep afterward.
If a child’s behavior worries you at any time of year, it’s worth talking to a pediatrician. This is general information, not medical advice.
The Bottom Line
The sugar high is one of the most durable myths in parenting, and one of the best-tested. In experiment after experiment, the sugar did nothing, and the belief did a lot. Next time the house is chaos on Halloween, you can blame the party.
For more everyday myths and mysteries, visit our Everyday Science section. And since the clocks change this weekend too, you might want to read why the “extra hour” isn’t what it seems.
