Seeing pictures of food with calorie information not only makes food less appetising but also appears to change the way your brain responds to the food, according to a study.
When food images appeared with the calorie content, the brain showed decreased activation of the reward system and increased activation in the control system, said researchers from Dartmouth College in the US.
In other words, foods that you might otherwise be inclined to eat became less desirable once the calorie content was displayed.
The study, published in journal 'PLOS ONE', is the first of its kind to examine how your brain makes food choices when calorie information is presented.
"Our findings suggest that calorie-labelling may alter responses in the brain's reward system when considering food options," said Andrea Courtney, who was a graduate student at Dartmouth at the time of the study.
"Moreover, we believe that nutritional interventions are likely to be more successful if they take into account the motivation of the consumer, including whether or not they diet," said Courtney, who is currently a postdoctoral student at the Stanford University.
For the study, 42 undergraduate students (ages 18 to 22) viewed 180 food images without calorie information followed by images with calorie information and were asked to rate their desire to eat the food while in a functional magnetic resonance imaging scanner (fMRI).
The images were obtained from either the food pics database or popular, fast food restaurant websites that post calorie information.
The 22 dieters and 20 non-dieters viewed the same set of images, including foods such as a cheeseburger, a side of French fries or a slice of cherry cheesecake.
On a scale from 1 to 4, they indicated how likely they would be to eat the food in the dining hall.
While dieters and non-dieters alike rated calorie-labelled foods as less appetising, this effect was strongest among dieters. Further, the researchers analysed responses in two brain regions that motivate eating behaviour: the nucleus accumbens (NAcc) and the orbitofrontal cortex (OFC).
Although all participants showed a decrease in activation in these areas when calorie information was present, dieters showed more similar activation patterns in the left OFC for calorie-labelled and unlabelled foods.
This finding suggests that dieters may consider calorie information even when it isn't explicitly present and builds on previous research suggesting that the presence of health cues can lead to healthier food decisions.
"In order to motivate people to make healthier food choices, policy changes are needed that incorporate not only nutritional information, including calorie content, but also a public education component, which reinforces the long-term benefits of a healthy diet," added Kristina Rapuano, who was a graduate student at Dartmouth at the time of the study and is currently a postdoctoral student at Yale University.