Student Questions: Sugary Behavior, Secondhand Smoke, and Wal-Mart

Answering more questions sent in by students.

by Brian Dunning

Filed under Feedback & Questions

Skeptoid #142
February 24, 2009
Podcast transcript | Listen | Subscribe

Today we're giving some more quick answers to questions sent in by students. Any student anywhere is welcome to ask anything about a current popular misconception, a science question that affects our daily lives, or just anything you've heard that doesn't seem to quite make sense. Today's questions are about how sugar affects children's behavior, the real risks of secondhand smoke, the popular hatred of Wal-Mart, omega-3 fatty acid supplementation, and whether radiometric dating is actually useful for determining the age of an object. Let's start with Andrew:

Hi, my name is Andrew and I want to know if certain food additives can affect children's behavior. Do certain food additives cause children to act in a more disruptive fashion, and can removing them from their diets help them behave in a more placid fashion? Thanks.

Certain additives like caffeine and alcohol certainly affect children's behavior in the same way they do adults, in fact to a greater degree because the children have such smaller body mass. But I think you're talking about more common ingredients like sugar or corn syrup. Nearly everyone has always accepted the belief that sugar makes kids hyperactive; in fact it's so deeply ingrained that even some researchers have had trouble accepting their own results. In one study, 35 children reported by their mothers to be "behaviorally sugar sensitive" were separated into two groups. Half were told they were given a sugary drink, half were told it was a sugar-free drink. Then the mothers played with the children and were individually interviewed. Overwhelmingly, mothers who were told their child was given sugar rated their behavior as hyperactive. In fact, all children received the same sugar-free drink. In this case, the perceived affect was confirmation bias by the mothers — where they picked up only on cues that supported their pre-existing conviction.

Another similar study found that 50 children whose mothers "knew" that their children's behavior was worsened by sugar were given a blinded test where the children were given either sugary or a sugar-free drink, and then observed — but this time the mothers didn't know which was which. No differences between the groups could be ascertained over three separate trials. And the lack of an effect extends to classroom performance, too. 16 hyperactive boys were given controlled diets of either sugar drinks or sugar-free drinks at measured intervals throughout two school days and were regularly given behavioral and cognitive tests. Again, there was no difference in performance between the groups.

Biochemically, the claim doesn't make sense for normal healthy children. The amount of sugar in the blood is carefully regulated by insulin. Whether you eat a lot of sugar or none at all should make no difference to your blood sugar level.

So Andrew, the evidence is pretty clear that sugary foods will not affect children's behavior, despite the widespread belief. The observed effect that all mothers can swear to is that they often see their children eating cake and juice at parties or other such gatherings, where the social environment does indeed contribute to mass insanity; and mothers quite naturally mistake correlation for causation.

Hey Brian. This is Adrienne Myers from Stetson University. Is there legitimate research showing that secondhand smoke is harmful?

This is a really interesting question. On the one hand you do have a rock-solid consensus of every major health organization in the world, including the National Institutes of Health, the Center for Disease Control, the World Health Organization, the Surgeon General's office, and the National Cancer Institute; that consensus being that there is no safe level of exposure to secondhand smoke. On the other hand you have an at least equal amount of research disputing this finding; research usually funded by the tobacco industry but also by consumer groups or think tanks like the Cato Institute. In addition, there is growing sentiment in the skeptical community along the lines of "No safe level? Come on..."

Usually when we have the scientists on one side and the interest groups on the other side of a science question, it's pretty easy to guess which side probably has the science right. And the scientists probably do in this case too. The ideal level of secondhand smoke is zero, just as the ideal amount of trans-fats you should eat is zero, and the ideal amount of alcohol to consume is zero. Nearly everyone consumes a non-zero amount of all three, and most people who don't overdo any of them will never encounter any ill effects. There's a big difference between living in a house with a chain smoker and the level of exposure from occasionally walking down the street and passing through someone's cigarette smoke.

The best conclusion is that the scientists are right that zero is probably ideal, but that a realistic low level of occasional exposure is probably harmless.

Hi Brian, I'm Jeff from Northeastern University in Boston, and my question is: Why is Wal-Mart singled-out and stigmatized as an evil corporation by the media, when many of their complaints seem to be applicable to other companies and businesses as well?

Wal-Mart truly is a lot bigger than any of the other apparently similar companies you can think of, so any complaint you'd have about any superstore is likely to apply to Wal-Mart to at least the same degree. Wal-Mart is the de facto poster child for anticorporate sentiment. When a Wal-Mart comes to town, small retailers who are unable or unwilling to adapt their businesses can often be put out of business. Although the requirement for businesses to adapt to changing market conditions has always existed independently of Wal-Mart, it can sometimes be a highly visible and dramatic change when a Wal-Mart comes to a small town, and so it always attracts attention. It's much like what happened when railroads first appeared, favoring some and abandoning others; and again when interstate highways did the same thing; and then again when Internet retailers began to appear and forced a paradigm shift across the board.

But that's only the initial objection to Wal-Mart as a company. When a lot of people hate you, a lot of microscopes get pointed at you; and many other criticisms are unearthed that (as you rightly point out, Jeff) do apply equally to many other companies. Some of these include Wal-Mart's resistance to unionization, its foreign product sourcing, low wages and lame benefits packages, and its exploitation of tax breaks commonly called corporate welfare. There's nothing about these criticisms that's unique to Wal-Mart; but since the public perception exists, it's a really easy target for opportunistic critics like documentary filmmaker Robert Greenwald, who capitalized on the sentiment with his 2003 film Wal-Mart: The High Cost of Low Price.

As the responsible skeptic can probably surmise, scholarly study of Wal-Mart done outside of pop culture is much more balanced. Most of the common criticisms of Wal-Mart are perfectly true, but they're hardly the complete picture. If you're interested in Wal-Mart's real effects on a community beyond what the protest signs reveal, you've got to dig in and read the research. Wikipedia provides a good list of links to a number of thorough studies.

Hi Brian, my name is Sarah and I love your podcast. I have a question about omega-3 fatty acids. Every seems to be in a fever about their health and cosmetic benefits, and I was wondering are they really worth the hype?

In my video Here Be Dragons I show a bunch of pictures of examples of pop pseudoscience, and one of them is a bottle of fish oil tablets, sold as an omega-3 fatty acid supplement. I take heat for that all the time: People are always emailing me and saying "Hey, omega-3 fatty acids are actually good for you!" And that's true, they are. Your body needs them, and it can't synthesize them; you have to get them from the food you eat.

In fact, fish oil and other omega-3 supplements are prescribed by doctors as a treatment for a variety of illnesses. In many cases, there's not yet a conclusive consensus on how well supplementation treats these conditions, but lots of research is ongoing.

However, one fact has been determined with fairly good certainty. If you are healthy, if you do not have a specific condition that fish oil is intended to treat, if you eat anything like a half-decent diet, omega-3 fatty acid supplementation has not been found to have any plausible benefit. This is pretty much true of nearly all supplement products. A normal diet in any industrialized nation provides more than enough of nearly every nutrient your body has a use for. Anyone selling a product on television or in your supermarket's supplement aisle that claims it's a super-duper life prolonger that will make you healthier than healthy is taking you for a ride.

Tip Skeptoid $2/mo $5/mo $10/mo One time

Does it have any value in the face of certain diseases or deficiencies? Quite probably. Does it have any value for a healthy person? No, Sarah, no hype is justified.

Hello Mr. Dunning. Recently I've grown a fancy to disproving creationism and theism. My question to you is of a creationist argument that carbon dating is inaccurate longer than 1000 years. I was immediately skeptical. So the question is, is carbon dating inaccurate, and how could I respond to such an argument?

This is a common objection that Young Earth Creationists raise to the scientifically determined age of the Earth. Radioactive decay rates are a known constant. By measuring the amount of an element in a compound and that of the element into which it naturally decays, a ratio can be established that tells us how long ago that compound was formed. There are more than a dozen commonly used types of radiometric dating, each optimal for a different type of compound, and each with its own error range and its own useful date range. Carbon-14 dating, that you mention, is used for establishing how long ago living matter died. Any scrap of wood or other organic matter stopped metabolizing carbon-14 when it died, and that carbon-14 in its cells has been decaying into carbon-12 ever since. How much is left tells us for a certainty how long ago it died. Carbon-14 dating is good for anything up to about 60,000 years ago.

Naturally, it's essential to know how much carbon-14 was in the environment throughout that period of time. Calibration scales have been established that tell us this. The amount of natural environmental carbon-14 is confirmed from a variety of sources. These include dendochronology, or tree rings; ice cores; ocean sediment cores; coral samples; and speleotherms, or cave formation samples. These combine to give us an extremely detailed, consistent, and precise knowledge of atmospheric carbon-14 levels throughout recent geological history. They account for volcanic events and even the era of atmospheric nuclear tests. These calibration sources are a great place to start your conversation with your friends. You can't deny radiocarbon dating without denying tree rings.

Other radiometric techniques can be used to date rocks and other objects on much longer time scales. While carbon-14 has a relatively short half-life of 5,730 years, the decay of potassium-40 to argon-40 has a half-life of 1.3 billion years, so potassium-argon dating is useful for dating the oldest rocks; but it's only accurate for rocks at least 100,000 years old. In addition to the useful date range, each method has a known error rate. For example, rubidium-strontium dating, with a half-life of 50 billion years, can date rocks as old as moon rocks up to about 3 billion years with an error of 30 to 50 million years, or about 1.5%.

Students, keep those questions coming! Just come to and click on "Answering Student Questions" for a simple form and instructions. If these guys did it, you can too. I'll look forward to hearing from you.

Brian Dunning

© 2009 Skeptoid Media Copyright information

References & Further Reading

Bowman, Sheridan. Radiocarbon Dating, Interpreting the past. Los Angeles: University of California Press, 1990.

Dawkins, Richard. The Ancestor's Tale, A pilgrimage to the dawn of evolution. New York: Houghton Mifflin Company, 2004. 519-523.

Hooper, L., Thompson, R., Harrison, R., Summerbell, C., Ness, A., Moore, H., Worthington, H., Durrington, P., Higgins, J., Capps, N., Riemersma, R., Ebrahim, S., Davey Smith, G. "Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review." BMJ. 1 Apr. 2006, Volume 332, Number 7544: 752-760.

Hoover, D.W., Milich, R. "Effects of sugar ingestion expectancies on mother-child interactions." Journal of Abnormal Child Psychology. 1 Aug. 1994, Volume 22, Number 4: 501-515.

Kirklin, Paul. "The Ultimate pro-WalMart Article." Ludwig von Mises Institute. Mises, 28 Jun. 2006. Web. 30 Dec. 2009. <>

NCI. "Secondhand Smoke: Questions and Answers." National Cancer Institute. National Cancer Institute, 1 Aug. 2007. Web. 30 Dec. 2009. <>

Reference this article:
Dunning, B. "Student Questions: Sugary Behavior, Secondhand Smoke, and Wal-Mart." Skeptoid Podcast. Skeptoid Media, 24 Feb 2009. Web. 10 Oct 2015. <>


10 most recent comments | Show all 44 comments

guys... if you have to resort to wiki to deal with biochemistry and physiology you are on a losing path.

Please, its a bit of an insult to the general reader.. Its sort of like saying, I know about biochem, look at this wiki answer..

That is just terrible.

Henk van der Gaast, Sydney
November 12, 2010 2:52am

Here is a suggestion as to how to carry out the sugar test. The false presumption seems to be that all children metabolise sugar in the same manner. So why not test that first with a test such as the glucose tolerance test.

Then test those children that show a less than desireable curve - especially reactive hypogylcaemia - in isolation from those with normal tests. This would be to stop behaviour that is a reaction to the behaviour of the other sample.

In my experience with some children sugar plays a major role in making bad situations worse. This may be about sweetness addiction - I don't know

Here in Australia we have a large number of breads made by one company under a very wide variety of brand names (including generics) and types, that include continental styles . I try to avoid them because they make me feel ill. The only link I know of is the flour and ingredient source. I pick them out every time

Phi, Sydney
March 14, 2011 7:39pm

Public health drives (as you suggested) are a common thing and visits to a GP are extremely helpful.

But examine this position you take on bread. You've mentioned this a number of times now.


1)how can you be sure it’s the flour? A product as simple as bread still has many variables.

2)have you been to see a specialist on the matter? You may indeed be crook you may want to do something about it.

After all, a verifiably tested and proven manufacturing error that you have presented for by authorities can prevent other people becoming as crook as you on your outlet’s bread.

An annual check up is free for we bronzed gods (read old codgers). The follow up visit after the biochem is critical.

An article by Brian on older men and health matters may be a good start to get us corporeal deniers to that check up.

“Hello this is Brian Dunning.. today we take a look at eternal youth”. Many men have a problem with leaving their teenage ..."

Henk van der Gaast, sydney, Australia
March 19, 2011 5:08pm

I'll answer you this one Henk, but for obvious reasons I cannot name the brands. I do know of tests carried out by industrial chemists on the breads concerned. They in fact did find that the firm was frequently exceeding maximum additive levels. I gained this information because my questions were so much on the button. All the breads i had major trouble with had the same corporate source. At the time i did not know that

I did find however it was better for me to avoid the usual additives altogether. If I have difficulty with bread from an independent bakers I look to see which brand of flour they are using - Often it is the same answer. Is it the flour? - it could be they are following millers instructions for use of their flour and buying additives from the same source - but I have found that sometimes their flour used domestically has the same effect.

Yes i have seen specialists on the matter. The advice for dealing with the worst problems was to use highly refined white flour for a time to restrict naturally occurring items or avoid bread altogether. It isn't gluten by the way - I use it in my own bread to raise the "apparent protein level" - about one teaspoon to 600 gms

I still get problems with other shelf breads but they are rarer and lesser.

As to getting the authorities to enforce their own legislation - mate this is Australia - they don't do that. Read about the loss of the rule of law here. Lawyers and judges are worried about it

Phi, Sydney
March 19, 2011 11:12pm

So it was not any clinical research that "proved" this. You have no way to distinguish which of the many factors it was. You can no less prove it was the flour, or the additives, or anything else.

That is not "answering" Henk at all really...

TomH, Kent
July 25, 2011 10:19am

I actually glutenise ahead.

Yes, you can buy flours with additives. I buy my flours in 12 or 25 kilo bags. Straight strong or meal.

I really dont get your point. If your specialist said all that i would be surprised it wasnt a psychiatrist.

Industrial chemist? I would have had food chemists do the job. They are at lidcombe and are very approachable

Henk v, Sin City NSW, Oz
September 10, 2011 12:49pm

Nearly 2 years on and we find that food and cooking hobbyists have a bit of a problem with the perception by people too slack to do the really simple stuff are actually suspicious of them.

Brian caught the change from the Old hypochondria to the new hypochondria on its cusp.

Furthermore, Brian also caught a supplement fad that has been worth many billions world wide and frankly stated;

" has not been found to have any plausible benefit."..

Says a lot for marketing of tank thought and one hell of a lot more for verifiability.

As to creationism? Its a lot more verifiable than alt medicine, more people believe in it..

Thats how its suppose to work? Right?


Henk v two years on.., sin city, Oz
August 7, 2013 11:10pm

Love your show---going through old episodes, and noticed a small faux pas... Carbon-14 decays to Nitrogen(via beta decay), not Carbon-12... Carbon-14 is created by cosmic ray bombardment of nitrogen in the atmosphere, and eventually becomes nitrogen again after decay... You can therefore think of Carbon-14 as rented nitrogen... :)

Steve, White Plains, NY
October 7, 2013 9:30pm

Not that I disagree in any way with the conclusion established by a plethora of studies that sugar consumption does not affect children's behavior. However, upon listening to this episode a second time just now, I noticed something that I wanted to point out.

The first of the several studies Brian mentions, were it the only study ever conducted on sugar's affect on children (which it's not, fortunately), would not be sufficient to conclude that the sugar-causing-hyperactivity-in-children phenomenom is not a real thing.

I say this because the study studied only children not given sugar, demonstrating only the confirmation bias present in the parents. It is possible for a real phenomenom to produce additional confirmation bias on top. To rephrase, the simple existence of confirmation bias stemming from a certain stimuli does not mean there is not a smaller-but-still-real effect that may have created the tendency for confirmation bias in persons aware of the effect.

For example, imagine a study where two groups of people were either told they were receiving placebo aspirin or real aspirin. In fact, both groups are given placebo aspirin. You may well find that the group that was told they received real aspirin would report a stronger analgesic effect, demonstrating confirmation bias resulting from taking aspirin. This wouldn't prove that aspirin doesn't work.

Anyhoo, I posted this mainly as a tool to sharpen my critical thinking skills. Any thoughts?

Paul, Irvine, CA
June 3, 2014 7:28pm

P.S. Just to clarify, my comment above is not an attempt to side with the sugary-foods-cause-my-kid-to-be-hyper people. It's more an attempt to critically evaluate methodological flaws with studies regardless whether it's findings agree or disagree with what scientific research has previously established..

I don't think that sugar-consumption makes kids hyperactive, however I feel that the first of the studies Brian mentioned has methodological flaws that we as skeptics should have identified. I know we would have identified it's flaws were the conclusion counter to the prevailing consensus.

It's important we apply the same level of skepticism and critical evaluation to studies that reinforce our arguments and to studies that contradict our arguments. Better that we find these flaws first before our opponents do.

Paul, Irvine, CA
June 8, 2014 7:16pm

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