A novel way to treat weight gain may involve limiting our exposure to light at night—whether that light comes from our bedside lamps, the light pollution that sneaks through our windows or the electronic devices we use as we drift off to sleep.
Randy Nelson, who chairs the Department of Neuroscience in the West Virginia University School of Medicine, is exploring how maintaining a truly dark sleeping environment may make it easier to keep weight off.
Being exposed to light at night changes how the “clock” genes that regulate our biological rhythms are expressed. Normally, encountering light upon waking in the morning synchronizes our internal body clock. “Think of it like an old-fashioned watch that gains 15 minutes every day. The way that it could still work as a good 24-hour clock is if you set this watch back 15 minutes whenever you wake up,” said Nelson, who directs basic science research for the WVU Rockefeller Neuroscience Institute.
But exposure to light at night can “hijack these clockworks,” he said, and the effects can be surprising. He and his colleagues have found that being exposed to light at night—even if it’s as dim as a nightlight—correlates to weight gain in animal models. Instead of confining their eating to the usual time of day, the animals ate around the clock, and they weighed more than their counterparts that experienced typical bright days and dark nights.
Nighttime light does more than disturb regular eating patterns. It also interferes with metabolic processes. “It’s well established that the feeding cycles are phase-locked—to use an engineering term—to the circadian cues,” said Nelson. “If you’re a day-active creature, like most of us, then we eat during the day. That’s when our metabolism is set up to process food, when our insulin starts going up, when we’re ready to deal with calories coming in.” Calories we take in at night don’t benefit from these favorable metabolic conditions. Our bodies don’t process them as much, and they tend to get stored as fat.
“In West Virginia, we have tremendous potential to impact diabetes without medication. Luckily there is a lot of great work on this around the state and here at WVU,” said Emma Eggleston, dean of the WVU Eastern Campus and director of the Center for Diabetes and Metabolic Health. “Evidence shows us that there are multiple lifestyle approaches that work to prevent and even reverse diabetes. We have many tools in the toolkit, but food is one of our most powerful.”