Can Late-Night Snacking Cause Sunburn?

When it comes to skincare, our bodies are watching the clock, apparently. A new study maligns one of my favorite things to do–eating when I’m supposed to be asleep—and the skin’s ability to protect itself from the sun.

In a collaborative study between the O’Donnell Brain Institute at UT Southwestern Medical Center and UC Irvine, researchers found that mice that ate at abnormal times during the day and night effectively disrupted their skins’ biological clock, leaving them more susceptible to sunburn and long-term skin damage. Specifically, irregular food intake was found to be responsible for the reduced expression of XPA, a critical gene that repairs DNA when it's damaged by factors like UV rays, radiation, and free radicals.

To test the skin’s response to disruptive feeding schedules, mice were placed on one of five schedules that ranged from ad libitum (unrestricted access) to different four-hour intervals of restricted feeding throughout the day (early day, midday, early night, and long day, which lasted eight hours). The mice were partially shaved, and UVB was applied to their backs during day and night sessions.

Researchers found that not only is food intake responsible for the release of certain skin genes, like XPA, but that shifts in healthy eating schedules also changed the body’s ability to heal itself. Those mice who were fed during the day (which is abnormal for nocturnal animals) experienced the greatest degree of skin damage when exposed to UVB rays, in part because of the reduced expression of XPA during the daytime, when the mice should have been resting. Conversely, mice that were fed during the night did not experience the same shift in XPA cycles, and were less exposed to sun damage.

"This finding is surprising,” Dr. Joseph S. Takahashi, the chairman of neuroscience at the O’Donnell Brain Institute, told Science Daily. “I did not think the skin was paying attention to when we are eating."

Though plenty more research is needed to understand the effects on diurnal (daytime) creatures such as ourselves, Takahashi cautions that the best way to watch out for our skin from a dietary perspective is to stick to a schedule that reflects the time by which you should be asleep. "It is likely that if you have a normal eating schedule, then you will be better protected from UV [light] during the daytime," Takahashi, said. "If you have an abnormal eating schedule, that could cause a harmful shift in your skin clock, like it did in the mouse."

At the very least, if you’re planning a beach trip the morning after a midnight fridge raid, do your skin the favor of lathering on a nice, high SPF sunscreen (experts say 50 is about the highest that actually does what it says) and reapply often.

Now that that's over with, what's your go-to midnight snack?