January 14, 2014

Health food research marketing

The Herald has a story about better ways to present nutritional information on foods

“Our study found that those who were presented with the walking label were most likely to make healthier consumption choices, regardless of their level of preventive health behaviour,” Ms Bouton said.

“Therefore, consumers who reported to be unhealthier were likely to modify their current negative behaviour and exercise, select a healthier alternative or avoid the unhealthy product entirely when told they would need to briskly walk for one hour and 41 minutes to burn off the product.

“The traffic light system was found to be effective in deterring consumers from unhealthy foods, while also encouraging them to consume healthy products.”

This sounds good. And this is a randomised experiment, which is an excellent feature.

However, it’s just an online survey of 591 people, about a hypothetical product, so what it actually found was that the labelling system was effective in deterring people from saying they would buy unhealthy foods, encouraging them to say they would consume healthy products and made them more likely to say they would exercise. That’s not quite so good. It’s a lot easier to get people to say they are going to eat better, exercise more, and lose weight that to get them to actually do it.

Another interesting feature is that this new research has appeared on the Herald website before. In October 2012 there was a story based on the first 220 survey responses

Not only were people more likely to exercise when they saw such labels, they also felt more guilty, Ms Bouton said.

“My findings showed that the exercise labelling was significantly more effective in both chocolate and healthier muesli bars in encouraging consumers to exercise after consumption.

“It increased the likelihood of having higher feelings of guilt after consumption and was more likely to stop [the participant] consuming the chocolate bar with the exercise labelling.”

The 2012 story still didn’t raise the issue of what people said versus actual behaviour, but it did get an independent opinion, who pointed out that calories aren’t the only purpose of food labelling.

More importantly, the stories and the two press releases are all the information I could find online about the research. There don’t seem to be any more details either published or in an online report. It’s good to have stories about scientific research, and this sort of experiment is an important step in thinking about food labelling, but the stories are presenting stronger conclusions that can really be supported by a single unpublished online survey.

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »