Too many of us are running on empty — an estimated 50 to 70 million of U.S. adults aged 18 and older suffer from sleep or wakefulness disorder, according to the Centers for Disease Control and Prevention. What’s more, on top of feeling like a zombie, a lack of sleep is associated with serious health consequences, like obesity and diabetes. Scientists were unsure about some of the mechanisms underlying this connection. But a new study published in the journal Current Biology suggests it may be a matter of genetics.

The study authors established that a gene called translin integrates the sleep and metabolic state, the process your body uses to make energy from food. It's a conserved gene, meaning it is similar across multiple species. And on days you don't eat much or at all, this gene can keep you from falling asleep, the study authors wrote. Researchers figured this out by studying the sleep habits of fruit flies, whose sleep cycles are remarkably similar to those of humans — they get most of their sleep at night and poor sleep can affect their performance the next day. Fruit flies are also known to sacrifice their sleep for their quest to find food.

Researchers put fruit flies on specific diets in order to measure their sleep, blood sugar and pressure levels. They created various scenarios for the fruit flies, where they could test each gene one at a time to help narrow down the ones that impact their sleep and wake cycle.

For an even closer look at these effects, researchers conducted a RNAI screen of the flies' nervous system to identify all possible genes associated with certain phenotype or trait changes, specifically the genes required to keep hungry flies awake.

Results showed when translin was reduced, starving flies slept as peacefully as they would have if they had a full stomach. But when it was present, starving fruit flies were not able to sleep.

This gene seems to regulate the flies' sleep and metabolic state, study author Kazuma Murakami said in a statement. Interestingly, researchers noticed that the gene does not regulate energy, blood sugar levels or feeding behavior, which suggests that an individual's sleep behavior is not a "consequence of general metabolic dysfunction or blunted response to starvation." So lack of sleep may be a result of translin's presence in response to starvation.

"In humans, sleep and feeding are tightly interconnected, and pathological disturbances of either process are associated with metabolism-related disorders," said Dr. Alex C. Keene, corresponding author of the study. "Despite the widespread evidence for interactions between sleep loss and metabolic dysfunction, little is known about the molecular basis of this interaction and how these processes integrate within the brain."

Previous studies have linked sleep deprivation to increased appetite and insulin resistance. People who are chronically sleep deprived are more likely to suffer more serious consequences, such as obesity, diabetes, cardiovascular disease, and metabolic syndrome.

These findings reveal that translin can inhibit sleep in the absence of food, which provides scientists some insight "into how the brain integrates and controls the expression of complex behaviors," said Keene.

Source: Murakami K, Yurgel M, Stahl B, et al. Translin is Required for Metabolic Regulation of Sleep. Current Biology. 2016.