There have been numerous studies that connect sleep deprivation or insomnia with increased desire for not-so-healthy food. Now, a new study is suggesting it’s not only the brain that plays a role: smell could also be a real junk food partner in crime.
Published in eLife, the study recruited 29 men and women, aged 18 to 40, and divided them into two groups. One got a normal night’s sleep, then four weeks later, were only allowed to sleep for four hours one night. The experience was reversed for the second group.
After each of the nights, they were offered breakfast as well as a buffet of snacks, and researchers tracked what, and how much, they ate. Before the feast, they were put in an fMRI scanner and presented with a number of different food odors, as well as non-food smells, and had their brain activity tracked.
Each group of participants showed more activity in the piriform cortex—the part of the brain that receives input from the nose—when sleep deprived. They also ate more calorie-dense foods, like doughnuts, chocolate chip cookies, and potato chips, after their short-sleep nights.