New research from Oxford University reveals that the brain is drawn to high-fat foods, even when a lighter alternative is available. A study by Fabian Grabenhorst and his colleagues found that the orbitofrontal cortex, which is responsible for sensations and the attractiveness of food, becomes more active when recognizing fatty foods. The study used vanilla-flavored milkshakes with varying fat and sugar content, as well as pig tongues to measure the sliding friction of different compositions in conditions similar to the human mouth.

The results showed that friction decreased as the fat content of the shake increased. The researchers then tested 20 participants who were asked to rate their willingness to pay for each milkshake after tasting. Brain imaging revealed that the differences in composition and pleasantness of the shakes were reflected in reactions of the orbitofrontal cortex.

The preference for high-fat foods was partly explained by mouthfeel associated with sliding friction, which affects people’s food choices. In another part of the experiment, test subjects were able to choose their favorite curry from three options with different fat content without knowing they were being observed. Those whose orbitofrontal cortex reacted strongly to greasy mouthfeel in shake experiment piled on fatty meals on their plates.

Grabenhorst told Nature magazine that these findings may help develop low-calorie foods that still have a satisfying mouthfeel. The study was published in The Journal of Neuroscience