Adults who received approximately four hours of sleep the previous night were exposed to odors like potato chips or cinnamon rolls, as well as nonfood scents like fir trees. Weeks later, the same participants were asked to sniff the same scents after receiving a full eight hours of sleep.

When exposed to the aroma of foods, subjects who were sleep deprived showed more brain activity in their piriform cortexes and orbitofrontal cortexes - two regions of the brain associated with smell.

— Read more at Do you eat more when you're tired? Blame your nose, says study at WCBV.