Sugar doesn’t cause hyperactivity

Here is Aaron Carroll at The Incidental Economist:

Let’s cut to the chase: sugar doesn’t make kids hyper. There have been at least twelve trials of various diets investigating different levels of sugar in children’s diets. That’s more studies than are often done on drugs. None of them detected any differences in behavior between children who had eaten sugar and those who hadn’t. These studies included sugar from candy, chocolate, and natural sources. Some of them were short-term, and some of them were long term. Some of them focused on children with ADHD. Some of them even included only children who were considered “sensitive” to sugar. In all of them, children did not behave differently after eating something full of sugar or something sugar-free….

In my favorite of these studies, children were divided into two groups. All of them were given a sugar-free beverage to drink. But half the parents were told that their child had just had a drink with sugar. Then, all of the parents were told to grade their children’s behavior. Not surprisingly, the parents of children who thought their children had drunk a ton of sugar rated their children as significantly more hyperactive. This myth is entirely in parents’ heads. We see it because we believe it.

Even when science shows time and again that it’s not so, we continue to persist in believing that sugar causes our kids to be hyperactive. That’s likely because there’s an association. Times when kids get a lot of sugar are often times when they are predisposed to be a little excited. Halloween. Birthday parties. Holidays. We may even be causing the problem ourselves. Some parents are so restrictive about sugar and candy that when their kids finally get it they’re quite excited. Even hyper.

This does not mean that there aren’t a ton of great reasons why our kid should not ingest large quantities of sugar. As almost any parent knows, sugar has been linked to cavities and the obesity epidemic. Just don’t blame it for your child’s bad behavior.


Nonsense! My anecdotal experience trumps controlled experiments any day!

It should, actually.

No, it shouldn't.

It should generally, yes. Particularly if your anecdotal experience is confirmed by large groups of other people.

Unfortunately for you, Josh, having thousands of idiots believe in something does not make it even slightly true.
Controlled experiments trump collections of idiots any day.

Still a bit skeptical. From what I've seen of these tests they are poorly controlled. For instance, they generally just assume sugar substitutes cannot have similar effects to sugar. (If a molecule fits into the "sweet" receptor on the tongue, it is likely to also fit other receptors that sugar tends to fire.)

It might even be that the act of tasting something sweet itself leads to euphoric, hyperactive behavior. I would be interested to see more tests in which the control is something bland, or not eating at all.

Yeah, I've seen studies like "at a party we gave 30 kids soft drinks; half of them were sugar free. And all the kids ran nuts!"

Is there a study where they give some kids milk and some kids water and some kids high sugar drinks and then sit them down in separate classrooms to learn how to calculate the surface area of a prism?

I love the way that he warns us against old wives' tales and then ends with "As almost any parent knows, sugar has been linked to ...the obesity epidemic". Ain't 'linked to' a wonderfully, um, adjustable sort of phrase?

>sugar has been linked to …the obesity epidemic

Fantastic point.

In other news, Rush Limbaugh has been linked to racism, and heavy snow in New England this weekend has been linked to Global Warming.

On the other hand, at least there are much, much, much more plausible "links" between sugar and getting tubby than any blather about Limbaugh and "racism" - even ones demonstrably causal and completely uncontroversial in their accuracy*.

"Links" is totally a cheap shot** in and of itself, but in this case it's defensible on the grounds of parsimony rather than to be leading.

(EG. "Limbaugh has been linked to racism" as far as I know, includes only links of the tenuous and unimportant sort, which when used seriously - rather than as you do here - is meant to tar him with things he realistically doesn't deserve.

"Sugar is linked to obesity" is more like "We don't want to say that sugar causes it outright, because it's more complex than that, but the linkage is substantial and we have excellent reasons to believe it to be causal". Which is fair and true, by my understanding of the science.)

(That said, "obesity epidemic" is a sign of shoddy work. And sugar isn't magically causing it all by its lonesome.)

* Not to say there haven't been hysteric ones along the lines of "sugar is poison that is killing us all". But those are equally irrelevant.
** It's a good heuristic for a claim you should be very wary of - or at very least the presentation.

Nah. Rush Limbaugh is a racist. And the snow in New England is a direct result of Global Warming.

I think what makes kids hyper is all the moms at the get-together saying "they are going to be so hyper!"

When I was a kid, I never got a sugar high. Eating just about anything made us more energetic afterward. Candy, meat, broccoli... Didn't matter.

I believe it.

Most kids probably have pretty healthy endocrine systems. My old and savaged system crashes after I eat sugar. I don't recall getting a sugar rush ever.

I'm not too surprised by the sugar result. My parents believed the "sugar makes him hyper" theory right up until they noticed that it only worked with a few sugar sources: Sprite didn't seem to have any effect, but Coke and chocolate (i.e. caffeine) did.

But this meta-study doesn't show any behavioral changes with chocolate, either? A recognized physical and psychological stimulant? I don't have access to the full text here, but that sounds pretty dubious.

The low-quality "chocolate" loaded with artificial emulsifiers, palm oils and other disgusting filler that people commonly feed children (e.g. Hershey's) has very little caffeine in it. A bar of Hershey's milk chocolate contains 9 mg of caffeine, whereas a cup of coffee has about 130 mg and a diet coke has 47 mg. In other words, eating an entire bar of Hershey's chocolate is the equivalent of drinking less than .5 ounce of coffee or 1.5 ounces of diet coke. Even on a child, this does not have much of an effect.

assuming you let your kids eat that kind of chocolate!

Children get expensive vegetables and cheap chocolate.

What Tall Dave said. Also, the parent's perception may indeed have been skewed into some kind of confirmation bias by being told the children had sugar when in fact the drink was sugar free. However, that means the grading simply obscures any finding, not that it disproves that sugar may indeed cause a higher degree of hyperactivity. Similarly, the children's own activity may have been influenced by the fact that they have tasted sweets, and hence triggers behavioral activity.

The most that can be said from these studies is that we cannot say for certain that sugar is a cause of hyperactivity. Even double blind studies can be weak in this regard, and these studies are a far cry from that. On the facts as given, "science" has disproved nothing.

I don't think that's the most we can say. Having not read the studies, they may very well go even beyond this, but at least we can say that sugar causes no more hyperactivity than artificial sweeteners.

I am incorrect: the paper cites 12 double-blind studies:

"Although sugar is widely believed by the public to cause hyperactive behavior, this has not been scientifically substantiated. Twelve double-blind, placebo-controlled studies of sugar challenges failed to provide any evidence that sugar ingestion leads to untoward behavior in children with Attention-Deficit Hyperactivity Disorder or in normal children. Likewise, none of the studies testing candy or chocolate found any negative effect of these foods on behavior."

I am still skeptical, especially given that the mere fact that something does not have more of an effect than placebo does not in fact rule out causation for all cases. And of course the choice of placebo matters a great deal, as do the controls. One of the problems inherent in all such studies is that the larger the sample size, the harder it is to get good controls, yet the smaller the sample size, the less robust the study. Combine that with the complexities of child behavior, physiology, and the subjective nature of the evaluators, and it seems there is a great deal of room for error in drawing conclusions as to causation.

I think I'll give the anecdotal observations of millions of parents some weight on this as against the 12 studies.

I really wonder if the anecdotal evidence applies only to sweets- as I suspect- or if it also applies to baked potatoes, fruit juice, and other foods consisting mostly of simple sugars. In fact, such foods likely have more "sugar" (glucose/fructose) as a percentage of their weight than sweets which often have a substantial amount of fat (depending on the type, of course). Do parents believe that their kids get super hyper after eating a baked potato? Because there is no logical reason why they should behave differently with pixie dust than a baked potato.

so what if there are 12 studies
as a PhD who does this sort of thing, let me let you into a little PhD secret: there are lots and lots of garbage studies out there.
Since the document is behind a paywall, we don't know what the 12 studies were, how well they were done, how many kids, if they were truly double blind placebo controlled etc etc
Not only that, there is a problem: these same authors appear to have published the same thing in 1996, so they are getting two publications out of hte same thing.

Have things changed much since 2007?

That certainly reads like propaganda. Of course I agree that all simple carbohydrates are the same and HFCS is not some special villain. But, simple carbohydrates are just about the worst possible thing you can eat. They have no nutritional value and are the quintessential "empty calories," leading to excessive calorie intake and insufficient nutrition. While the link claims that studies show there is no relation between sugar intake and diabetes, simple carbs in large quantities provoke dramatic insulin responses which have deleterious effects on the body. Perhaps "sugar intake" is a poor proxy for intake of high glycemic index carbohydrates.

how do you know that all simple carbohydrates are the same ?
You can start with how they interact with the stomach and intestine, possibly activating different transport receptors and feedback loops, go onto to gut microbiome physiology, then serum transport proteins with low affinity, followed by permeability thru blood brain barrier and kidney, not to mention DNA polymorphisms, in , say Fructose 1,6 bisphosphatase. etc etc
sorry - you can start with neural feedback circuits that tie into tastebud receptors that respond differentenly to to sucrose, fructose, glucose, not to mention trace contaminants....

"In my favorite of these studies, children were divided into two groups. All of them were given a sugar-free beverage to drink. But half the parents were told that their child had just had a drink with sugar. Then, all of the parents were told to grade their children’s behavior. Not surprisingly, the parents of children who thought their children had drunk a ton of sugar rated their children as significantly more hyperactive. This myth is entirely in parents’ heads. We see it because we believe it."

So, his favorite study is one that proves the existence of a confirmation bias among the parents, but doesn't disprove the possibility of a link between sugar and hyperactivity? How fascinating.

I agree with Mark. His favorite study doesn't test how kids respond to sugar, since it says they were given 'sugar free drinks'. The headline is misleading, even more than the studies or the disbelief in them.

The sugared kids may get hyper who then cause the other kids to get hyper. I want to see the following study. Separate the kids into 3 groups. Group 1 gets sugar and gets paired with group 2 that doesn't. Tell half the parents of each group that their kids got sugar. Observe the results (Result A). Then, somewhere else, group 3 gets NO sugar. Tell half the parents that their kids got sugar. Observe the results (Result B). Then compare Results A and B. If sugar causes kids to be hyper AND the hyper kids cause the non-sugared kids to be hyper (which I suspect) then Result A should be different from Result B.

This is an american thing. In many other countries children are given sugar to calm down! In Brazil, for instance, water with honey or sugar is given to soothe anxiety in adults and children alike.

i have been telling people this for years and they refuse to believe it.

In America(georgetown universtiy hospital) they give sugar water to babies in the neo natal inensive care units to put them to sleep.

I am a parent of three and I do not observe a strong causal relationship between sugar and hyper active childish behavior. I do observe a high correlation between parents who continually repeat sugar high mythology and parents who are lame.

The article cites Aaron Carroll at The Incidental Economist, who in turn links to someone else (twelve trials)
If you go to that link, you see paywalled research.
So, how many of you have access to this $$ article, and have actually looked at it ?
I did do a few minutes of pubmed searching, and many of the studies, as you would expect given the difficulty of research involving humans, have small numbers of people under conditions where the "placebo" control is not really a placebo control - For instance consider this study, I quote from the abstract
'A challenge design was employed to investigate the effect of sucrose consumption on the behavior of 12 preschool children. On separate experimental days, subjects were tested individually with either a challenge sucrose drink (2 gm/kg body weight) or a placebo drink sweetened with aspartame. Fifteen-minute observations of each child during free play were made at 15, 45, and 75 minutes after ingestion of the drink."
Now one thing that would invalidate this study is if the kids can taste a difference between sucrose and aspartame....anyone else think that could be ??

some evidence of sleazy journalism; check out the citatin and this link on pubmed
Crit Rev Food Sci Nutr. 1996 Jan;36(1-2):31-47.
same 12 studies from 1996 - is that acceptable scholarship

If you look at the few areas where biomedical research has tried really, really, *really* hard to come up with an answer, like in the role of cholesterol in heart disease (see WESCOPS or SSSI) you see that 12 small studies is Nothing; you cna have lots and lots of studies and still be totally wrong

So, some kids were given a "sugar-free drink." What ELSE was in that drink? Were any of the kids sensitive to red food dyes that may or may not have been in those drinks? (mine are, and I have unsolicited accounts from other parents and from teachers to back that up.) What about to artificial sweeteners? to artificial flavorings? What kind of sugar? Glucose? Fructose? Sucrose (a mix of both)? HFCS (which in many cases contains mercury)? My kids are also sensitive to fructose, to the point that more than one small juice box renders them spacy and weepy and combative in the space of 20 minutes; this lasts for several hours (and again, plenty of third-party commentary, anecdotal though it may be, to back this up as well). Were ANY of the children tested for any food sensitivities that might account for the behaviors? And since when is "sugar" a single monolithic substance?

This article tells us nothing, really - it's a splashy headline that's designed to let parents off the hook for bad food choices brought on (optimistically) by misinformation (and pessimistically by willful ignorance).

Wow, some really in depth sceptism shown here. It's a good thing none of you got involved in the obesity, smoking, or drinking health scares. They have the pretty much the same level of pretend science, fake science and hidden agendas as this study does.

That's funny, I was going to ask how many of the folks who instantly determined that this research was airtight and incontrovertible are also AGW skeptics.

You think the caffeine in these soft drinks might make the kids hyper? Nah, lets just focus on sugar.

Comments for this post are closed