Seeing a picture of a tempting menu item is one thing. It’s very much a different thing when that image includes the number of calories you’d be consuming according to a study conducted at Dartmouth and published in the journal PLOS ONE.
Forty-two students looked at 180 food images with their brain monitored by a functional magnetic resonance imaging scanner. Some images included calorie information while others did not. Whether on a weight loss diet or not, subjects rated foods as less appetizing when the calories were part of the image. This effect was more pronounced in subjects who were actively trying to lose weight.
After analyzing MRI data, researchers theorized that calorie information might be able to alter how the brain’s reward system responds to visual stimulus.