The position of calories on menus influences how much people eat

Where calorie information is placed on menus influences how much people order and eat, according to new research by the ESRI’s Behavioural Research Unit. The researchers conducted a carefully controlled behavioural experiment in which consumers were initially unaware that their lunch choices were being observed.

The study was funded by the Department of Health and involved a representative sample of consumers, who were given different lunch menus at random. It found that people ordered and ate less when calorie labels were put on menus, but the effect depended on exactly where the calories were shown.

Some menus had no calorie information, some had calories displayed just to the right of the price, and some just to the left. The largest impact was recorded when calorie labels were displayed just to the right of the price, in the same font and at the same size. This resulted in a 19% drop in the calories consumers ordered for lunch and a 37% reduction in the calories they ate – a substantial effect.

The researchers were also able to track consumers’ eye movements using an infrared camera as they read the menu – the first scientific study to manage to do this while people make real food choices. Consumers given a menu with calorie labels placed just to the right of the price looked more at the labels. When asked later, they were also more likely to know how many calories were in their lunch.

One concern with calorie posting is that it could make people less likely to enjoy their food. The study found no evidence for this, however. Diners shown calorie information rated their satisfaction with lunch at least as highly as those not shown the calories.  

“Controlled experimental studies like this can be used to pre-test policies before they are implemented,” said Dr Deirdre Robertson, member of the ESRI’s Behavioural Research Unit and lead researcher on the study. “Opinions about calorie posting differ and can be strongly held, so it is important to provide objective evidence about the likely impact. Our results show not only that calorie posting changes behaviour, but also that seemingly small changes to the format influence how well people understand and respond to the information.”

The research was commissioned as a pre-test of a proposed policy to introduce calorie posting on menus, which is a commitment under the Department of Health’s Obesity Policy and Action Plan.