Sleepless nights can really take a toll on your body, and science says a lack of sleep can even play a role in why you crave junk food. Recently, researchers at the Feinberg School of Medicine at Northwestern University presented a paper at the Cognitive Neuroscience Society’s annual meeting in San Francisco that suggests that sleep deprivation can make you more sensitive to food smells.
In the study, researchers divided participants into two test groups: one assigned eight hours of sleep and one assigned only four hours of sleep. Participants were then presented with “savory and sweet high-caloric food odors” (aka junk food) and “non-food control odors,” and asked to rate each on its “pleasantness and intensity.” While the participants were rating the smells, functional magnetic resonance imaging (fMRI) was used to measure brain activity. The experiment was repeated a few weeks later, but with all participants assigned to get 8 hours of sleep.
Results showed that participants who were tired had greater brain activity in areas associated with olfaction (the piriform cortex and the orbitofrontal) when smelling food than those who had a “regular” night’s sleep; however, the increase in brain activity wasn’t linked to non-food smells.