Just as move-in week and the return of late-night study sessions cause college students to lose sleep, a new project by University of Wisconsin researchers has found sleep deprivation may play a role in late night snack binges.

A new study conducted by UW researchers demonstrates the effects of sleep deprivation on hedonic, or reward-seeking, eating behaviors. The study is the first to show how overactive brain chemistry can lead to hedonic eating when people are sleep deprived. Such results have clinical implications and may provide a partial explanation for the eating habits of college students, according to Marcy Braun, a registered dietician with University Health Services.

Research studies performed on humans have long confirmed overeating in times of sleep deprivation. Brain scans and surveys show people are drawn to unhealthy, carbohydrate-rich foods, such as soda and dessert, when they have lost sleep, she said.

“You can definitely tell that when people are sleep deprived. They need … quick-acting energy,” Braun said.

Typically, the brain coordinates with other parts of the body to adjust caloric intake. Brian Baldo, assistant professor of psychiatry and lead author of the study, likens the brain to a thermostat. Like a thermostat, which turns on the heat when the temperature of a room is too low, the brain sends signals that trigger us to eat when peripheral signals from the rest of the body are too low, Baldo said.

“Feeding is a chemical challenge to the body [through which] peripheral hormones change the size of a meal,” Baldo said.

However, previous studies showed no association between sleep deprivation, changes in peripheral signals and increased eating.

Baldo and Ruth Benca, professor of psychiatry and Wisconsin Sleep Center research director, respectively, explored this phenomenon in a study conducted on rats. A moving belt jarred one group of rats awake to simulate sleep deprivation. Results from this group were compared to rats on a reduced diet and rats exposed to the moving belt while awake, Baldo said.

Analysis of rat brain scans in the study revealed sleep deprivation was a likely cause of the overexpression of opioid peptides, particles which can lead to an experience of intense pleasure. This indicated the opioid system, which is central in reward systems, is overactive in sleep-deprived rats, Baldo said.

The current study therefore provides the over-activation of reward centers as one possible explanation for increased snacking in sleep-deprived humans, Baldo said. Sleep deprivation can lead to an increased regulation of opioid peptides, sticking genes in the “on” position and resulting in excessive eating, he said.

Available data suggests that overactive opioid systems recover when sleep is replenished, Baldo said. In future work, Baldo would like to study other chemical changes that could drive overactive opioid systems. The effects of sleep deprivation on the opioid systems of overweight or obese individuals also will make for interesting future study, he said.

The study gives insight into a realm that is not easy to control. While sleep-deprived students may be prone to eating unhealthily, Baldo emphasizes that these new studies mark correlations between sleeping and complicated eating behaviors that may “destigmatize snacking problems under sleep loss.”

The clinical implications of the study are far-reaching, Brown said. The study results may help individuals who are trying to lose weight, since results may suggest that simply getting more sleep may help curb unhealthful snacking, she said.

Brown recommends students combine awareness with regular eating to combat excessive eating under sleep deprivation. Adding energy-dense, protein-rich foods, such as peanut butter, to snacks may also limit unhealthy choices, she said.

Still, hedonic eating processes driven by sleep loss are hard to control, Baldo said. Both Brown and Baldo agree, however, that study results have the potential to target drugs that regulate cravings and other eating behaviors.

Brown said experimenting with getting an extra hour of sleep each night for one week can help determine how sleep deprivation impacts an individual and could positively impact both quality of sleep and eating behaviors.