According to a new study, obesity can cause poor sleep and not the other way around, contrary to what is often assumed.
It has been repeatedly proven that poor sleep promotes weight gain. In humans, acute sleep disturbances can lead to increased appetite and insulin resistance. People who sleep less than six hours a night chronically also have a higher risk of obesity and type 2 diabetes. However, it is not clear how sleep and diet are related. According to a new study published in PLOS Biology, it is indeed obesity that can lead to poor sleep.
“We wanted to know what sleep really does. Sleep deprivation and other chronic diseases like diabetes are related, but this is just a link. It is not clear whether not getting enough sleep is the cause of the tendency to become overweight or perhaps obesity is the cause of the tendency of not getting enough sleep”, says Alexander van der Linden, associate professor of biology at the University of Nevada and co-author of the study.
To investigate the relationship between metabolism and sleep, he and his colleagues worked with microscopic worms called Caenorhabditis elegans (C. elegans) and modified a gene called KIN-29 in them to turn off a neuron that controls sleep. As a result, the worms have lost their ability to sleep. Researchers then discovered that the level of adenosine triphosphate (ATP), the body’s energy exchange currency, had significantly decreased in insomniac worms.
“This suggests that sleep is an attempt to save energy; it doesn’t actually cause energy loss,” says co-author of the study David Raizen, associate professor of neurology and a member of the Chronobiology and Sleep Institute in Penn.