Study Finds too Much Light at Night May Lead to Obesity

According to a study conducted at Ohio State University, authored by doctoral student of neuroscience Laura Fonken and professor of neuroscience Randy Nelson, being exposed to light during nighttime may lead to obesity, even if no physical activity or amount of food consumed change from one’s regular nighttime habits. Really.

Researchers exposed a group of lab mice to a dim light throughout the night over an eight week period, without changing their physical habits or amount of consumed food, and the mice had a 50% gain in mass compared to the other group of mice that were living with a regular dark night cycle.

Luckily, the research isn’t saying that light beams touching the skin make people fatter, but that a constant light cycle ends up changing the times when the mice eat, which in turn makes the mice eat when their metabolism is slower. The researchers believe constant light changing the metabolism is possible because the light could affect the levels of hormone melatonin, which affects the metabolism. They also theorize that light affects the expression of clock genes, which affect when animals feed and are active, directly linking a constant exposure to light to the mice eating at different times.

From this, the researchers theorize that humans who are active during the nighttime, even if they aren’t overeating and even if they are being physically active, may still continue to gain weight because their metabolism isn’t working as efficiently due to the exposure to sources of light, including television and computer screens.

So, if you’re a night owl and are reading this at four in the morning, and wondering why you’re still gaining weight even though you barely eat at night and just got home from the gym, it may be because the glow of your computer monitor and the dim light on the ceiling fan are attacking your metabolism and slowing it down.

(EurekAlert! via Boing Boing)