CATES: Study: Obesity linked to artificial light

Yesterday, a friend told me she had heard on the news about a study that linked TV use during sleep to obesity.  My reply to her was “I have to see the study before I believe that”. I said that because every weight loss plan out there claims to have “studies” that support, but many of those studies the conclusions are statistically borderline, the populations are tiny, the time periods are short, the study is heavily biased (for instance, the drug maker is paying researchers and participants doing the study), or something else that just makes the study weak. And linking obesity to TV while sleeping—-the premise alone sounds crazy. Weight loss studies bring out the cynic in me quickly, and this one sounded like it would be among the typical studies.

So with my cynicism in hand, I looked for the study. And I found it. “Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women. It was published in the Journal of the American Medical Association (JAMA) in their June 10, 2019 edition. That alone supports a good study. There are a class of publications called “peer-reviewed journals”, every profession has them. JAMA is a peer reviewed journal for the medical profession. In a peer reviewed journal the articles have to go through pretty strict criteria and be reviewed by experts in the field before they are published. What that means in everyday life is an article published in JAMA is going to have more validity than something that is published in Wikipedia—where anyone can say anything about a subject.  The next thing I looked at was the study size and how long it lasted. In this study over 43,000 women were studied for 5 years. So again, it hit the checks for a good study, large number of people were studies over al oong period of time. Lastly the data has a strong statistical significance, and there was no apparent bias. In other words, this is a really good study!

I am sure from seeing my picture you all know I struggle with my weight. I have tried pretty much every diet known to man—including bariatric surgery with varying degrees of success. I also developed the habit decades ago of sleeping with the TV on—I worked nights for years, and it drowned out the noises outside that would keep me awake—and it’s a habit that has stuck with me. I actually have a hard time sleeping in a quiet room after years of keeping the TV on at night. Because of those two things, this study really caught my attention—and it makes me wonder if that is not part of the reason (certainly not the whole reason) I struggle so much.

The researchers found that women who have on artificial lights in their environment—not just TV, but any sort of artificial light while they sleep weight about 11 pounds more on average than women who sleep in a dark environment. Because the study was so big and over such a long period of time, they were able to eliminate variables such as age, activity, and natural light and hone in on artificial light as the common factor. The study did not look at if changing sleep habits helped people lose that weight. That was suggested as something that should be studied in the future.

So while the researchers didn’t and couldn’t conclude that if you are a person that sleeps with some form of artificial light, and you change that habit to sleeping in a dark room you will lose weight, it is certainly food for thought. We do know from previous studies that increasing sleep time to 7-8 hours has some correlation with weight loss, so it does make sense that improving sleep quality by getting rid of artificial light would help too. Personally, I am going to try it, my thought is it certainly can’t hurt. The National Sleep Foundation has a good website on this and other things you can try to improve the quality of your sleep at Let me know if you decide to try changing your sleep habits and how it works for you.