Publishing their findings in the British Journal of Nutrition, the researchers led by Tamara Bucher of the University of Newcastle, Australia, say this is the first systematic review to look at how position interventions – altering the proximity and order of food – can influence food choice.
Whittling the number of studies from 2540 down to a final 18 that adhered to all criteria and were included in the review, the researchers looked at both single healthy or unhealthy items, such as water, fruit and vegetables, cereal bars, chocolate or crackers as well as more complex, canteen-style buffets which had between eight and 11 products repositioned.
Although there are various definitions of the term nudging, for the purposes of this review it was defined as any intervention that involved changing the non-economic properties (ie cost) or placement of objects within micro-environments – home, workplace or cafeteria – in order to change health-related behavior.
Food choice was defined as food selection or probability of food choice, including product sales and food consumption (in grams or energy intake).
Out of the 18 studies that were included in the review, 16 showed a positive impact of nudging – participants were encouraged to make a healthier food choice. In the two studies where no positive impact was recorded, the adjusted position was a very minor change and all foods remained within reach. “This indicates that the strength of the effect appears to depend on the type of positional manipulation (order v. distance), as well as the magnitude of the change, or how far away foods are placed.”
The tactics also seem to work irrespective of weight status; two studies differentiated between participants who were a healthy weight and those who were overweight, and found that positional nudges were effective in both cases.
Meanwhile one study took into account socio-economic status and reported that it had no influence on the effectiveness of nudge techniques. According to the authors of the review, this finding is in line with other studies which have shows that the techniques occur at a sub-conscious level, and therefore have an equal impact regardless of weight or social status.
However, although the reviewers find that food position does indeed influence choice, quantifying its impact is more difficult.
“Although the evidence that food position inﬂuences food choice was consistent across studies, it was not possible to evaluate the impact and effect size of these types of choice architecture interventions on actual food consumption and subsequent health outcomes,” they write. “Harmonised indicators are required that would allow comparability between experiments or interventions.”
They therefore urge all future research conducted in the field to use energy (kJ/kcal) or weight (g) as outcome measures of changes in food selection and intake.
In light of their findings, they urge people in charge of food organisation or food outlet design to be aware of their responsibility to organise ‘foodscapes’ in an optimal way "to stimulate consumption of healthy foods and to reduce the consumption of unhealthy foods that then could support healthy workplace initiatives. In practical terms, this means that low-energy, nutrient-dense products such as fruits and vegetables should be placed in easily accessible and prominent positions.”
Source: British Journal of Nutrition
“Nudging consumers towards healthier choices: a systematic review of positional inﬂuences on food choice”
First published online 22 March 2016, doi:10.1017/S0007114516001653
Authors: Tamara Bucher, Clare Collins, Megan E. Rollo et al.