Do Night-Lights Make You Fat?
Posted: January 5th, 2011, 7:51 am
Read this article in an Email this morning. Interesting concept.
Do Night-Lights Make You Fat?
Falling asleep to the glow of a muted bedroom TV or night-light is a common practice that seems benign... but it might be making you fat! Researchers at Ohio State University (Columbus) compared a group of juvenile mice that spent their eight nighttime hours in dim light (the equivalent of having a TV on in a dark room) with a group on a normal dark-night schedule. After just one week, mice from the slight-light environment had gained much more weight -- and the extra weight piled on so fast that at the end of the eight-week study the mice that had slept in dim light had gained 50% more than those kept in nighttime darkness. Glucose tolerance (related to, and a common companion of, insulin resistance) was impaired in the light-at-night group as well.
A Circadian Upset
Laura K. Fonken, a graduate research associate in the school’s department of neuroscience and psychology, filled me in on the findings, which were recently published in Proceedings of the National Academy of Sciences. She speculated that dim light at night may have disrupted the normal circadian clock in the mice, affecting the genes that prepare the body for predictable events, including eating. She said that the dim-light mice did not ingest more calories than the other mice, nor did they become less active -- the problem was a result of eating more frequently at times when they were normally inactive, when their metabolisms burned fuel less efficiently. In a second experiment, the researchers withdrew access to food during inactive periods. The mice took in the same amount of daily calories overall, and this time the mice in a dim-light group did not gain weight.
While rodents are nocturnal and humans are not, Fonken told me that light affects both species similarly, which is why the study findings have implications for us. We know, for instance, that there is a correlation between shift work and higher body mass index. It may be because their schedules make it necessary for shift workers to eat when their metabolisms are at low points. But, said Fonken, it also may be that low light at night triggers the desire to eat at off-hour times -- which would also explain people’s propensity to reach for after-dinner snacks in front of the TV or to get up during the night to eat. At present, these are merely hypotheses, she said, further research is needed.
In the meantime, for our own bedtimes, Fonken advises turning off the TV, the computer and the light in the bathroom and avoiding night-lights and lighted clock radios. A darkened room may indeed dampen the desire to eat at the wrong times, and it may come with a bonus as well -- better rest.
Source(s):
Laura K. Fonken, BS, graduate research associate, department of neuroscience and psychology, Ohio State University, Columbus.
Do Night-Lights Make You Fat?
Falling asleep to the glow of a muted bedroom TV or night-light is a common practice that seems benign... but it might be making you fat! Researchers at Ohio State University (Columbus) compared a group of juvenile mice that spent their eight nighttime hours in dim light (the equivalent of having a TV on in a dark room) with a group on a normal dark-night schedule. After just one week, mice from the slight-light environment had gained much more weight -- and the extra weight piled on so fast that at the end of the eight-week study the mice that had slept in dim light had gained 50% more than those kept in nighttime darkness. Glucose tolerance (related to, and a common companion of, insulin resistance) was impaired in the light-at-night group as well.
A Circadian Upset
Laura K. Fonken, a graduate research associate in the school’s department of neuroscience and psychology, filled me in on the findings, which were recently published in Proceedings of the National Academy of Sciences. She speculated that dim light at night may have disrupted the normal circadian clock in the mice, affecting the genes that prepare the body for predictable events, including eating. She said that the dim-light mice did not ingest more calories than the other mice, nor did they become less active -- the problem was a result of eating more frequently at times when they were normally inactive, when their metabolisms burned fuel less efficiently. In a second experiment, the researchers withdrew access to food during inactive periods. The mice took in the same amount of daily calories overall, and this time the mice in a dim-light group did not gain weight.
While rodents are nocturnal and humans are not, Fonken told me that light affects both species similarly, which is why the study findings have implications for us. We know, for instance, that there is a correlation between shift work and higher body mass index. It may be because their schedules make it necessary for shift workers to eat when their metabolisms are at low points. But, said Fonken, it also may be that low light at night triggers the desire to eat at off-hour times -- which would also explain people’s propensity to reach for after-dinner snacks in front of the TV or to get up during the night to eat. At present, these are merely hypotheses, she said, further research is needed.
In the meantime, for our own bedtimes, Fonken advises turning off the TV, the computer and the light in the bathroom and avoiding night-lights and lighted clock radios. A darkened room may indeed dampen the desire to eat at the wrong times, and it may come with a bonus as well -- better rest.
Source(s):
Laura K. Fonken, BS, graduate research associate, department of neuroscience and psychology, Ohio State University, Columbus.
JF