I found some research that was quite fascinating, very left-field but I’m sure will be of interest to many people.
Many people have issues with their weight, mostly too much weight. But what if there was a simple way to lose weight? A method that involved no dieting, no watching what you eat, no exercise, no drugs, no side effects….sounds too good to be true, right?
Well, researchers in the United States claim to have made a discovery that your weight is directly related to when you get sunlight each day. In a nutshell, the study found that the earlier you got your light in the day, the lower your BMI (Body Mass Index). 20% of the participants’ BMI was directly related to the time of the day they received their light.
"Light is the most potent agent to synchronize your internal body clock that regulates circadian rhythms, which in turn also regulate energy balance," said study senior author Phyllis C. Zee, M.D. (Professor of Neurology and director of the Northwestern Medicine Sleep and Circadian Rhythms Research Program at Northwestern University Feinberg School of Medicine).
"The message is that you should get more bright light between 8 a.m. and noon." About 20 to 30 minutes of morning light is enough to affect BMI.”
Our lifestyle is very much an indoor lifestyle now, and inside light is around 200-300 LUX (a measure of brightness).
As a comparison:
- A full moon at night is approximately 0.27-1 Lux
- A cloudy day is approximately 1,000 Lux
- Direct sunlight is approximately 32,000-100,000 Lux
This study found that 500 Lux was the magic number associated with a lower BMI. 500 Lux is possible to get in some office environments, but this would be unusual. On the other hand, even a cloudy day provides twice the amount of light needed.
The study examined the habits of 26 Men and 28 women (average age of 30) who all wore wrist monitors to measure their light exposure and sleep patterns for 7 days. During the study, participants had to stick to their normal routine and keep a food diary.
The overall light exposure, duration and intensity did not appear to be linked to BMI, but when the participants were exposed to light did make a significant difference.
My thoughts on this study
The limitations are that it had a relatively small number of participants (54) and that the nature of the study was not designed to prove whether the light exposure actually caused the weight loss. As such, there could well be other factors affecting the conclusions, such as whether skinny people are skinny because they are more active and tend to be up and about in the mornings?
However, we know that circadian rhythms, changes in hormone levels and other biological processes occur throughout the day and that they play a significant role in regulating metabolism and weight. We also know that light is a potent mechanism for synchronizing your body clock, so that gives a degree of credence to this study - it’s not just a completely random observation plucked out of thin air.
I put this is the ‘definitely worth a crack’ category. If something has zero side effects, zero cost and probably other positive spin offs then why not have a go? If you do decide to do this and be a little scientific about it, I’d be most interested in hearing your results. Until then, enjoy the morning sun.
Daniel King, MSc (hons)
