The Simple Thing That Might Make You Thinner

You might want to throw those curtains open first thing in the morning from now on, because a new study suggests people who get most of their daily light exposure in the morning have lower BMIs. Researchers from Northwestern University asked 54 participants with an average age of 30 to wear wrist monitors so their light exposure, activity, and sleep patterns could be measured for seven days. Participants also recorded their eating patterns in food logs.

The results show that, even controlling for non-light exposure factors, exposure to morning light accounted for 20 percent of participants' BMIs — in other words, those who had exposure to early rays weighed less. On the other hand, recent research published in Endocrine Society reveals that nighttime light exposure (coming from your smartphone, tablet, laptop, or TV) actually increases the risk of obesity.

Scientist don't quite know the details of light's effect on weight, but Kathy Reid, research associate professor of neurology at Northwestern University and co-author of the study, suggests light has an impact on metabolism, hunger, and satiety. “People aren’t spending a lot of time in really bright light,” Reid said, “But light is clearly a strong signal to the body.” As long as you remember to wear sunscreen, spending more time in the sun can't hurt, right?