Using phones, tablets, laptops and other devices in the hours before bed could make it harder to lose weight — or may even lead to weight gain over time. In a new study published in Scientific Reports, researchers studied 10 adult males exposed to LED, OLED, or dim light for four hours prior to falling asleep inside a metabolic chamber. Those exposed to LED light experienced a significant reduction in their ability to burn fat while they slept. This isn’t the first time LED light has been linked to weight gain. A 2019 JAMA Internal Medicine study found adult women who slept with a television on in their room had higher rates of obesity at the beginning of the study and were almost 20 percent more likely to have gained 11 pounds or more by the end of the study. Some sleep experts suggest that exposure to blue light leads to shorter REM sleep, which has been linked to weight gain.