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Sugar and ADHD: A Bad Mix?

Gummy bears or grapes? Why studies disagree on sugar and ADHD.

Boris Dzhingarov, Candy Store ``Candy Kitchen`` in Virginia Beach, VA
Source: Boris Dzhingarov, Candy Store ``Candy Kitchen`` in Virginia Beach, VA

As a kid I ate a lot of candy. And I got a lot of cavities. On days when it basically rained candy, like Halloween or Christmas, I took it to a whole another level. And then I usually got hyper, restless, and silly. I assume it just too much candy.

If you’ve ever wolfed down a large amount of candy in a short period of time (especially as a kid) then you probably know what a sugar rush is. Sometimes it’s called a “sugar high.” Or maybe you’ve seen your own kids on a sugar high. Science doesn’t really support the idea of a sugar high, but I’m not so sure. Common wisdom for instance tells us don’t give kids too much sugar, especially if it’s too close to bedtime.

Beyond our run-of-the-mill sugar highs, many parents think that ADHD and sugar are a particularly bad mix. Too much sugar makes ADHD symptoms worse. That’s the logic. The “sugar high” aggravates the already vulnerable hyperactivity or inattention. Kind of like a sugar high squared. But once again, the research linking sugar and ADHD is not totally supportive. It’s mixed.

One recent study from Iran for instance suggested that a diet rich in diary, homemade fruit juice, vegetables, and low-fat meat may be better for ADHD symptom management in kids than a diet with high amounts of sugar. They compared the two groups who were each randomly assigned to one of the diets. Both groups also took the ADHD medication, methylphenidate. This make sense in that medication is often considered the most effective form of intervention for ADHD, so dietary changes would most likely be used in addition to medication, rather than in place of medication. The results were positive in that the healthier diet led to reduced ADHD symptoms, but surprisingly this held for the kids’ inattention symptoms and not their hyperactivity symptoms. Of course since it’s only one study, it needs to be repeated with other additional studies to show these benefits more conclusively. The details of this study by Ghanizadeh and Haddad is at:

But other studies don’t support such a link. So there’s disagreement. So does that mean there’s no link between ADHD symptoms and sugar? Should we assume that sugar has not effect on ADHD at all? Well I say no and here’s why.

First, research doesn’t disprove the theory that sugar makes ADHD worse, it’s just mixed on it. Some studies show a relationship between sugar and worsened ADHD behaviors and others don’t. That’s not the same as saying there’s no relationship.

Second, we need to rethink how we understand research. The mass media (especially TV) wrongly trains us that study A “proves” this and study B “disproves” that, as if each individual study settles the matter completely. That might boost viewership but it’s not accurate.

All studies are imperfect and they all differ from each other in many ways. For studies on ADHD and sugar there might be differences in the ages of the kids involved, the amount or type of sugar eaten, the way ADHD symptoms are measured, how many people dropped out, and so on. And then there might be other things that influence the ADHD symptoms other than sugar, like mood, sleep, or medication, that the study does not even measure. So there are many reasons why similar studies can have different outcomes.

But even though all research is incomplete and imperfect, that doesn’t mean it’s useless. Rather, most studies represent a snapshot at a moment in time. And like a picture album you need to look at multiple snapshots to get the idea of what you’re seeing. In other words, look for a trend across numerous studies to know what is going on, not just one individually. If multiple studies all point in the same direction, despite their differences and flaws, then it is a more powerful sign than an individual result.

Research is helpful but it’s not the answer for everything. On a very practical and personal level, pay attention to what you observe in your own kids. If your son buzzes too much after a jar of candy, don’t let him eat that much anymore. If your daughter is more difficult than usual after eating a lot of holiday candy, then manage her intake. You may have heard recently about added sugar in our diets. Many products that aren’t noticeably sweet have sugar added to them, like pasta sauce. So read those labels too! Finally, know that many other products we buy are sweetened with sugar alternatives like aspartame, agave, and corn syrup. Take note of how much of these are in the foods you buy.


Ghanizadeh, A., & Haddad, B. (2015). The effect of dietary education on ADHD, a randomized controlled clinical trial. Annals of General Psychiatry, 14: 12.

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