Next time you're lying awake at 3 a.m. worrying about a project at work, the weird pain in your foot and climate change, you can add a new concern to your repertoire: weight gain because your insomnia can apparently make you fat! You're welcome.
Researchers at Northwestern University have published a new study on Aug. 22, 2018 in the journal Science Advances showing that even one night of sleep loss — yes, just one night — can cause changes in fat and skeletal tissue at a molecular level. Granted the study was small; researchers took tissue samples from a group of just 15 college-age male subjects after they spent a night without sleep and after a night of regular sleep and compared them. The experiment was designed to mimic shift work, where people are often up all night.
We've long known that insomnia, shift work and jet lag have adverse effects. Not getting enough sleep can stress a body out, which means you'll produce more cortisol, a hormone that signals your body to store fat for use when you have to sprint away from that saber-toothed tiger. (Ha ha, body, there's no tiger! I'm just constantly stressed out!)
Other studies have shown that several nights of sleep deprivation can disrupt your body's ability to use insulin. Excess insulin ends up being stored in your liver, which can lead to obesity and diabetes. And to make things even worse, sleep deprivation can increase production of a hormone called ghrelin that tells your body you're hungry. Research has shown that people tend to eat an extra 300 calories after being sleep deprived, and those calories are often from fatty foods. Take that, liver.
Many of these studies had bigger pools of participants (one involved 60,000 nurses), but they were mostly observational. This recent study, led by Jonathan Cedernaes, MD, Ph.D., who is a postdoctural fellow at Northwestern University's Bass Lab, was small, but it delved further into the body's mechanisms for all of these changes at the DNA level. The researchers found increased activity in genes connected to prediabetes and diabetes, as well as genes related to inflammation, injury and stress. To cap it all off, they also found that sleep loss leads to skeletal muscle breakdown.
So even after one night of sleep loss, our bodies shift at a molecular level to increase fat and decrease lean muscle mass. Terrific.