Are midnight snacks making your sunburns worse?

Warm summer nights were made for leisurely meals al fresco and twilight strolls with frozen treats (vegan ice cream float, anyone?). But these late-night snacks may spell disaster for your sun-powered #99DaysofSummer adventures. A recent study from the University of Texas Southwestern Medical Center and the University of California, Irvine, reveals a new reason to padlock the fridge after sunset: Eating at night could make you more susceptible to skin damage—from sunburns and skin aging to cancer—from UV rays. (Yikes!)

For the study, two groups of mice were put on different feeding schedules. One group ate at night (which was normal for the nocturnal critters), while the other was switched to a day-time feast. Those that ate at an abnormal time experienced more damage from UVB light the next day. The reason, the researchers believe, is that the shifted mealtime caused a certain skin-repairing enzyme to be less active during the day.

“If you have an abnormal eating schedule, that could cause a harmful shift in your skin clock.”

Why is this the case? Essentially, your skin has a biological clock, and messing with your routine can throw things out of whack.

“It is likely that if you have a normal eating schedule, then you will be better protected from UV during the daytime,” says Joseph Takahashi, a lead author on the study. “If you have an abnormal eating schedule, that could cause a harmful shift in your skin clock, like it did in the mouse.”

More research (including some non-rodent experimentation) is needed to come to any firm conclusions, but Takahashi and his co-author Dr. Bogi Andersen, MD, were surprised by this apparent connection between your dermis and when you eat. “It’s fascinating to me that the skin would be sensitive to the timing of food intake,” Dr. Andersen says.

Well, consider this a reason to try meditating before bed instead of munching—that spirulina popcorn recipe will make a much better mid-afternoon snack.

To be sure you’re totally safe with UV rays, here’s the smart woman’s guide to sun protection. And these are the 11 best—and editor-approved—natural sunscreens.