A recent study has brought out that increased exposure to light at night is associated with obesity and metabolic disorders.

The study was conducted by a crew of researchers from the Departments of Neuroscience and Psychology, Ohio State University, Columbus, Ohio, and the Israeli Center for Interdisciplinary Research in Chronobiology, University of Haifa. The results are outcome of study performed on mice, which appeared in Proceedings of the National Academy of Sciences.

It was discovered that mice, which were exposed to dim light during the period of their sleeping gained 50% higher weight, as compared to mice kept in the dark. Even the physical activity and exercises didn't reduce their weight.

Some of the male mice were subject to LAN (light at night) and the consequent effect on their BMI (body mass index) was assessed. It was found that the mice that were exposed to light at night had higher BMIs and lower glucose tolerance level in comparison to the mice kept in the dark. Also, eating the habits of mice exposed to light were different from those who remained in dark. At night, the mice kept in LAN ate more than half their food which they consume in the day time.

So, researchers expressed that in humans also, late night eating could be a major reason of obesity. The authors wrote, "The 24-hour rhythm that regulates the state of our internal energy levels and metabolism is controlled by an internal biological clock that works in parallel with and responds to light information". They added if this clock is interrupted, there is a disturbance in the metabolism of body.