If you’re looking for an easy way to eat less of an unhealthy food put a mirror nearby, a new study suggests.

In this study from the Cornell Food & Brand Lab, researchers decided to see if the near presence of a mirror in a consumption setting could reduce the perceived taste of unhealthy food.

They had 185 undergraduate students chose between a chocolate cake and a fruit salad then evaluated its taste in a room with a mirror or with no mirrors around. Those who selected the chocolate cake evaluated it less tasty in the room with a mirror compared to those with no mirrors around. However, the presence of a mirror did not change the taste of the fruit salad.

“A glance in the mirror tells people more than just about their physical appearance. It enables them to view themselves objectively and helps them to judge themselves and their behaviors in a same way that they judge others,” explains lead researcher Ata Jami of the University of Central Florida.

This finding suggests that placing a mirror in dining rooms and other eating spaces so that diners can see themselves eat can be an effective way for individuals and restaurants to encourage healthier eating practices, according to the study, which appears in The Journal of the Association for Consumer Research.