IS EXPOSURE TO LIGHT AT NIGHT CAUSING YOUR WEIGHT GAIN? It has been suggested in a report online in the Proceedings of the National Academy of Sciences that some of the obesity increase may be due to an increased exposure of light at night. Also, for those that do shift work. They believe this increased exposure to light at night disrupts the release of melatonin, which is a hormone produced by the pineal gland in the brain. According to coauthor and Ohio State University professor of neuroscience and psychology Randy Nelson what they observed is that light at night is an environmental factor that may be contributing to the obesity epidemic in ways that people don’t expect. Dr. Nelson looked at the effects of nighttime light exposure in 8 week old male mice. The animals were exposed to 24 hours of constant light, a standard light-dark cycle which consisted of 16 hours of light and 8 hours of darkness and also 16 hours of light and 8 hours of dim light. This is last variable is to mimic those living in industrialized nations. As early as one week after the testing began there was a greater increase in body mass observed among the mice exposed to content light and those exposed to the dim light. Those exposed to the standard 8 hours of darkness did not experience this increase in body mass. At 4 weeks the constant light and the dim light groups showed impaired glucose tolerance. The mice that lived with light at night were getting fatter than the others according to lead author and doctoral student Laura Fonken. Dr. Nelson states that they conducted another experiment where there was a light-dark cycle and a dim light cycle, but the mice had continuous access to food. The dim light group seemed to eat at night where the dark cycle group did not eat. When food was restricted to the dim light group the weight gain didn’t occur. So it appears that your timing of eating may be very important to preventing weight gain. Also, controlling the melatonin levels in your body may be a factor in preventing weight gain as well. Now these experiments were done with mice and not humans so there also needs to be additional studies done with humans, but mice are very close in humans in regards to behaviors when exposed to certain things so at the very least this is something to take note of and pay attention to. When we watch a lot of TV at night and wonder why we are hungry this may be something that is contributing to that hunger. If this happens to you try a little experiment on yourself and 1 hour before going to bed turn off the TV and at least dim the lights. Also, don’t watch TV in bed with the lights on. See if it makes a difference in your sleep habits and if your hungers at night go away. For those that have trouble falling asleep this may be the ticket to training your body for sleep instead of eating at night.