People both ordered and ate less when calorie information was displayed on menus, and the effect was greater depending on where on the menu the calories were shown, a new study has found.
The finding is likely to inform the work of policymakers who are currently looking at making calorie postings on restaurant menus mandatory.
Researchers at the Economic and Social Research Institute (ESRI) tracked and recorded the eye movements of participants using an infra-red camera as they chose from a lunch menu. They were unaware their choice was part of the study.
Participants exposed to calorie information ordered 93 fewer calories (11%) relative to a control group who saw no calorie labels.
The impact was strongest when calorie information was displayed just to the right of the price, and in a similar font.
This resulted in a 19% drop in the calories ordered for lunch, and a 37% reduction in the calories eaten.
Dr Deirdre Roberston, co-author of ‘The effect of spatial location of calorie information on choice, consumption and eye movements’, just published in the journal Appetite, said that consumers looked more at the labels when they were given a menu with calorie labels placed just to the right of the price.
When asked later, they were also more likely to know how many calories were in their lunch, suggesting more informed decision-making.
The study found no evidence that calorie posting could make people less likely to enjoy their meal.
Diners who were shown calorie information rated their satisfaction with lunch at least as highly as those not shown the calories.
Dr Robertson said that their study — which was funded by the Department of Health and conducted last summer — was designed to “pre-test” possible Government regulations to introduce calorie-posting on menus, which is a commitment under the department’s Obesity Policy and Action Plan.
“Controlled experimental studies like this can be used to pre-test policies before they are implemented,” said Dr Robertson.
“Opinions about calorie-posting differ and can be strongly held, so it is important to provide objective evidence about the likely impact.
She said that policymakers may need to include specifications about content, size, colour, and position of calorie information when drafting the relevant regulations.