Mandarin Slices

Evidence That Nutrition Facts Don’t Always Change Behavior

Facts matter. Right? We like to think so. But the truth is that people act on emotion – beliefs and feelings – every bit as much as they do on facts. For a case study in how beliefs and feelings can triumph over facts, let’s take a look at a nutrition education program.

Teaching Children About Gardens and Nutrition

Last year, Rachel Scherr and colleagues published a study of gardening and nutrition education in the Journal of Nutrition Education and Behavior. It sounds like a great program. Teaching kids about gardening and nutrition is a noble pursuit.

However, Scherr was aiming higher. She and her colleagues believed that their program could fight childhood obesity. They conducted this study to support their beliefs. And their paper concluded that they found a “significant decrease in BMI percentiles.”

False Conclusions Based on an Incorrect Analysis

The claim of a significant effect on BMI was surprising. Nutrition education is a good thing, but programs like this – by themselves – seldom cause a drop in BMI. So a team of independent researchers took a closer look. Alexis Wood and colleagues found that the analysis was inappropriate and could not support the claims that Scherr was making.

Wood et al wrote the journal to request a retraction or correction. The journal published their letter. But Scherr et al declined to correct their false claims. Contacted by Retraction Watch about this matter, Scherr said:

At this time we are not planning for a retraction or correction as we had responded to the concerns of the critic in the response letter.

David Allison, the senior author on the retraction request, told Retraction Watch that this is a straightforward matter of facts. The analysis does not support the conclusions. Columbia professor Andrew Gelman was even more adamant. In his blog, he wrote:

Huh? So you’re clear that it’s a pilot study, but you still released a statement saying that your data “demonstrated that [the treatment] was effective”???

Noooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Standing Pat on Beliefs, Despite the Facts

And yet, Scherr et al are standing pat with their beliefs that they have an effective way to reduce BMI. Facts and statistical analyses do not sway them. The journal – so far – is letting this false claim stand.

If we expect rationality from the public and policymakers, such behavior from a scientific journal and researchers is completely unacceptable.

Click here for more about this situation from Retraction Watch. For the original study, click here. The letter challenging the claims of efficacy is here and the response is here.

Mandarin Slices, photograph © Marco Verch / flickr

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April 19, 2018