Being glued to your smartphone at night may not be so smart if you’re trying to stick to a healthy diet. In research presented at the 2019 conference of the Society for the Study of Ingestive Behavior, in the Netherlands, rats exposed at night to just 1 hour of blue light—the same type of light emitted by many digital devices like smartphones—consumed more sugar afterward than when they were not exposed to blue light at night.

It’s believed that retinal cells in the eye are extra-sensitive to blue light and send information to areas of the brain that regulate appetite. Of course, we need to see human studies before it’s possible to conclude that artificial light exposure at night can make us more likely to raid the pantry for sugary foods. However, it seems like a good idea to scale down screen time at night or use a program like f.lux, which dials back the blue light that devices emit after sunset.

Matthew Kadey, MS, RD

Matthew Kadey, MS, RD, is a James Beard Award–winning food journalist, dietitian and author of the cookbook Rocket Fuel: Power-Packed Food for Sport + Adventure (VeloPress 2016). He has written for dozens of magazines, including Runner’s World, Men’s Health, Shape, Men’s Fitness and Muscle and Fitness.

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