Be forewarned — this is not a column snack-food haters and the obesity obsessed will want to read.
But, fortunately, for those who take a dim view of cookies, chips and soda, this column is just about the only place where they'll run across this particular challenge to anti-junk food orthodoxy. So if you can't, or don't, want to handle information that will challenge your preconceptions about snack foods, click on your browser's "Back" button now!
Snack foods, as it turns out, may not be an important cause of weight gain in children after all. Harvard University researchers followed the snack food intake during 1996-1998 of almost 15,000 children aged 9 to 14 years. Their results were reported online in the International Journal of Obesity (search) on Aug. 17 — and virtually no place else since.
After statistically controlling for stage of development, age, height change, activity and inactivity, the researchers reported no relation between intake of snack foods and subsequent changes in bodyweight among the 6, 774 boys and an inverse relation (meaning snack food intake was associated with lower weight gain) among the 8,203 girls.
The researchers concluded, "Our results suggest that although snack foods may have low nutritional value, they were not an important independent determinant of weight gain among children and adolescents."
I know what you're thinking: only researchers bought and paid for by the snack food industry could produce such a shocking result and try to sell it to the public. So, who paid for the study? Was it Coca-Cola? Maybe Frito-Lay? What about M&M/Mars?
The study, as it turns out, was sponsored by the U.S. Centers for Disease Control and Prevention (search), the Boston Obesity Research Center (search) (a nonprofit organization funded by the National Institute for Diabetes and Digestive and Kidney Diseases), the National Institutes of Health (search) and the Kellogg Company (search).
So, yes, there was some industry funding (albeit not from a company primarily known for its snack foods), but it looks like the bulk of the effort was funded by the very federal government agencies that have been primary promoters of the current wave of childhood obesity hysteria. I guess we'll just have to consider the merits of the study, rather than dismissing it simply because its counterintuitive result works slightly in Kellogg's favor.
First, the study result might not be as surprising as you might think. There have been only two studies on snack food intake and weight change among adolescents, according to the Harvard researchers. While one study did report an association between snack food intake and adolescent weight gain, the other reported that snack food intake increased weight only among adolescents whose parents were overweight.
Moreover, the new study involved 10 times and 100 times, respectively, the number of study subjects as the prior two studies.
This study, like most other studies of disease in human populations (epidemiology), has its limitations. The children in the study were the children of nurses, not a random sample of all U.S. adolescent males and females. The study included few children of low socioeconomic status. The researchers collected data on snack foods, but not snacking occasions, so snacking on "healthy foods" was not assessed.
Despite its limitations, I tend to like epidemiologic studies like the Harvard study that report so-called "negative" results. Most studies that we hear about from the media — and the ones that I typically criticize — report weak statistical correlations between some factor like snack food intake and a health outcome like obesity. I tend to be skeptical of such weak "positive" studies because their underlying data usually isn't reliable enough to give me confidence in a weak statistical result.
The Harvard study data may have its limitations, but at least its researchers aren't trying to use poor quality data to support weak statistics. The researchers studied almost 15,000 kids for several years in an effort to link snack foods with weight gain. They couldn't do it. I find that to be a significant "non-result."
The Harvard study does not justify bad eating habits among children. But neither does it justify the demonization of snack foods. There are no "good" foods or "bad" foods. There are, however, "good" and "bad" eating habits. Snack foods can be part of a healthy diet. Make sure you tell that to the snack food haters who skipped this column.
Steven Milloy is the publisher of JunkScience.com, an adjunct scholar at the Cato Institute and the author of "Junk Science Judo: Self-Defense Against Health Scares and Scams" (Cato Institute, 2001).