Is your nightlight making you gain weight? A new study published in the Proceedings of the National Academy of Sciences suggests that getting too much light...when your body is expecting it to be dark...can be a factor contributing to obesity.

In the study, mice were exposed to 3 different light cycles:
-  A standard light-dark cycle (16 hours of light; 8 hours of dark)
- 24 hours of light
-  A modified light-dark cycle (16 hours of light; 8 hours of dim light)

Mice who were exposed to continuous and even dim light at night metabolized their food differently and gained 50 percent more weight than mice living in a natural light-dark cycle. All the mice ate the same amount of food and did the same amount exercise. But, while mice in normal light-dark conditions ate about two-thirds of their food during normal active hours, those that had extra light ate more than half their food during periods normally meant for rest - not the optimal time for a body to be burning calories.

Exposing mice to dim light i can be compared to people watching late night TV, keeping a computer screen on at night or having a night light on.