Brain food isn’t always a good thing.

Sleep deprivation actually causes the brain to feed off of neurons and synaptic connections, a new study published in the Journal of Neuroscience says.

In other words, when you don’t get enough sleep, your brain starts to eat itself. Yum.

Neuroscientist Michele Bellesi, from the Marche Polytechnic University in Italy, led a study examining the brain’s response to poor sleep habits using well-rested and overtired mice, Science Alert reported.

Groups of mice in the study were given varying amounts of sleep, ranging from a solid eight hours to being forced to stay awake for five straight days, according to the study.

During sleep, glial cells, or astrocytes, clear the brain of synapses to rejuvenate the brain, US News reported. Another cell is also at work when you’re snoozing. The microglial cell destroys “old and worn out cells via a process called phagocytosis — meaning ‘to devour’ in Greek,” Science Alert revealed.

These processes have a positive effect while you sleep, rewiring and replenishing the brain for the next day. Essentially, the brain is eliminating what’s irrelevant, holding onto what’s vital, and making room for new memories, Newsweek explains.

However, when you stay awake, the cells actually go into overdrive and start hurting the brain instead.

The study found that sleep-deprived mice had more active astrocytes than well-rested mice, which means the brain appeared to begin eating itself, US News reported.

“We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss,” Bellesi told Andy Coghlan at New Scientist. “But it may cause harm in the long term, and could explain why a chronic lack of sleep puts people at risk of Alzheimer’s disease and other neurological disorders.”

A scary 40 percent of Americans sleep six hours or less a day, according to the US Centers for Disease Control and Prevention. That means that 40.6 million adult brains are potentially gobbling themselves up.