Research appears to find link between bedroom light levels and obesity

Sleeping in a room with too much light has been linked to an increased risk of piling on the pounds, a study shows.

A team at the Institute of Cancer Research in London found women had larger waistlines if their bedroom was "light enough to see across" at night.

However, they caution there is not enough evidence to advise people to buy thicker curtains or turn off lights.

The study of 113,000 women was published in the American Journal of Epidemiology.

The women were asked to rate the amount of light in their bedrooms at night as:

Light enough to read
Light enough to see across the room, but not read
Light enough to see your hand in front of you, but not across the room
Too dark to see your hand or you wear a mask
Their answers were compared to several measures of obesity. Body Mass Index, waist-to-hip ratio and waist circumference were all higher in women with lighter rooms.

Prof Anthony Swerdlow, from the Institute of Cancer Research, told the BBC: "In this very large group of people there is an association between reported light exposure at night and overweight and obesity.

"But there is not sufficient evidence to know if making your room darker would make any difference to your weight.

"There might be other explanations for the association, but the findings are intriguing enough to warrant further scientific investigation."

Body Clock
One possible explanation is that the light is disrupting the body clock, which stems from our evolutionary past when we were active when it was light in the day and resting when it was dark at night.

Light alters mood, physical strength and even the way we process food in a 24-hour cycle.

Artificial light is known to disrupt the body clock by delaying the production of the sleep hormone melatonin.

Raggamuffin wrote:It might make a slight difference as disturbance of sleep does affect your body weight apparently. I should think it's the amount of junk food and chocolate that people eat which has more effect though.   

Ben_Reilly wrote:

Raggamuffin wrote:It might make a slight difference as disturbance of sleep does affect your body weight apparently. I should think it's the amount of junk food and chocolate that people eat which has more effect though.   

I've heard the same thing about sleep from plenty of sources, and I still can't quite figure out how that is supposed to work. To me, the deeper sleep you attain and the more time spent means the fewer calories you burn.

Only thing I can figure is that maybe sleep deprivation causes you to overeat in some way. But in general, sleeping is a classic calorie-conservation strategy, it's why the zoo is often no fun

Ben_Reilly wrote:

Raggamuffin wrote:It might make a slight difference as disturbance of sleep does affect your body weight apparently. I should think it's the amount of junk food and chocolate that people eat which has more effect though.   

I've heard the same thing about sleep from plenty of sources, and I still can't quite figure out how that is supposed to work. To me, the deeper sleep you attain and the more time spent means the fewer calories you burn.

Only thing I can figure is that maybe sleep deprivation causes you to overeat in some way. But in general, sleeping is a classic calorie-conservation strategy, it's why the zoo is often no fun