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How the proximity of unhealthy food affects the way you eat

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Researchers find that the closer unhealthy food is to you, the more likely you are to eat it, but the same isn't true for healthy food. 

There are three types of lies: lies, damned lies, and statistics. Deciding which of those categories former Cornell University professor Brian Wansink’s research falls into is probably semantics. But, by the end of 2018, 17 of Wansink’s published research papers, most focusing on consumer behaviour around food, had been retracted by scientific journals.

Even if you’ve never heard of Wansink, you’ve probably read some of his research. His studies have been cited more than 20,000 times. Findings, such as the idea that eating off smaller plates will make you eat less, or that hungry shoppers buy more calories than satiated shoppers, or that giving vegetables cool-sounding names will help kids eat more of them, were all produced by Wansink’s research laboratory at Cornell University.

So, if you shop while hungry, will you buy more food than you would if you’d just eaten? If you place a chocolate bar close to your chair, will you eat more of it during the day? And, if you were given a large bowl, would you serve yourself more ice cream than you would if you’d been given a smaller one?

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Yes, yes and yes would have been the answers, until recently, but after a group of scientists and journalists began delving into the research by the “world-renowned eating-behaviour expert”, they found some unsavoury truths.

By December 2017, six of Wansink’s papers had been retracted and 14 corrections issued. The retractions continued throughout 2018, culminating in September 2018 with the Journal of the American Medical Association retracting six of Wansink’s studies and noting that Cornell could not “provide assurances regarding the scientific validity of the six studies”. In September 2018, Cornell announced that Wansink had been removed from all teaching and research duties and would retire in June 2019.

So, where does that leave us in deciding which plates to use for dinner, or whether we need to place our chocolate at the far end of the kitchen?

Fortunately, Wansink isn’t the only researcher investigating our eating habits. In 2019, the journal Appetite published a study by University of Cambridge researchers. They investigated what effect the placement of more-nutritious or less-nutritious snacks had on intake.

Using raisins as a more-nutritious option and M&M’s candies as a less-nutritious option, they trialled four placements of the snacks on a table close to a person: the raisins near (20cm) and the M&M’s far (70cm); both foods near; the M&M’s near and the raisins far; and both far.

Under the guise of taking part in a relaxation and memory study, 248 people were placed under cognitive load – they had to memorise a seven-digit code – to distract them and compromise their usual self-control. They were then left alone for a 10-minute “relaxation break” with the two bowls of food.

At the end of the session, the researchers recorded how much of each snack the participants had eaten in the four different bowl configurations.

They discovered the likelihood of consuming healthier food (in this case, raisins) was unaffected by its placement and proximity to a less-healthy food. However, the likelihood of eating a less-healthy food (M&M’s) was influenced by closer placement and possibly by proximity to a healthier food.

So, it seems we are less likely to eat unhealthy foods such as chocolate when they are placed further away from where we are seated. This finding is in line with those of previous studies on the topic, including those by the now-infamous Wansink.

It remains to be seen whether many of Wansink’s other findings will be duplicated. Until that time, they remain a case of spurious statistical manipulation.

This article was first published in the March 2, 2019 issue of the New Zealand Listener.