Lights Out For Weight Loss

As a health journalist, I often write about the popular subject of how to lose weight. In my own life, however, keeping my weight down is not an issue even though I eat as much food as I want (or can!) every day. Yes, I follow a strict diet: no gluten, corn, soy or dairy. I also exercise. But I believe another factor helps. I sleep in a bedroom that’s pitch black at night.

Endless Light

We live in a society that produces an endless amount of light. Aside from our electric lights and street lights, we spend much of the day staring into televisions, cellphones and computer monitors. Even our alarm clocks, stoves and microwaves usually have small displays and clocks that throw off light.

Many scientists believe all that artificial light is throwing off our body’s natural rhythms, which are attuned to the Earth’s natural day-night cycle. In fact, a growing body of research suggests that our exposure to too much artificial light may contribute not only to higher cancer rates, but also to our society-wide weight gain.

Global Weight Gain

Researcher David B. Allison, Ph.D., of the University of Alabama at Birmingham thinks that human light pollution may be contributing to weight gain in humans and even animals. He believes that richer food and less exercise doesn’t seem to explain why so many animals (as well as people) are getting fatter.

He notes that “…Some of the animals [that have gained weight] might have become less active, but others would have remained at normal activity levels. Yet, they all showed overall weight gain. The consistency of these findings among animals living in different environments, including some where diet is highly controlled and has been constant for decades, suggests the intriguing possibility that increasing body weight may involve some unidentified or poorly understood factors.”

A research paper that Allison co-wrote for the British journal Proceedings of the Royal Society B observes that studies have shown that subtle changes in the amount of time spent in light or dark environments change eating habits. It is possible that increased light pollution in our industrial society may play a role in making mammals (that includes us) gain weight.

Light’s Negative Effects

Along with possibly adding pounds to your middle, too much light at night hampers release of the hormone melatonin from the pineal gland. In addition to its role in regulating the sleep-wake cycle, melatonin has been shown to lower blood pressure and body temperature and has also been explored as a treatment option for insomnia, hypertension and cancer.

A study at the Brigham and Women’s Hospital and Harvard Medical shows that exposure to light at night significantly restricts melatonin production.

“On a daily basis, millions of people choose to keep the lights on prior to bedtime and during the usual hours of sleep,” says researcher Joshua Gooley, Ph.D. “Our study shows that this exposure to indoor light has a strong suppressive effect on the hormone melatonin. This could, in turn, have effects on sleep quality and the body’s ability to regulate body temperature, blood pressure and glucose levels.

“Given that chronic light suppression of melatonin has been hypothesized to increase relative risk for some types of cancer and that melatonin receptor genes have been linked to type 2 diabetes, our findings could have important health implications for shift workers who are exposed to indoor light at night over the course of many years,” says Gooley. “Further research is still needed to both substantiate melatonin suppression as a significant risk factor for breast cancer and determine the mechanisms by which melatonin regulates glucose metabolism.”

Thick Drapes

To keep light out of my room at night, I use thick, blackout drapes over Venetian blinds on my windows while turning off and unplugging all of my electric devices. My alarm clock is battery-powered and does not have a lit display. I keep a flashlight by the side of the bed to use if I need to get up at night and have to find my way around.

I also go to sleep at the same time every night and get up at the same time every morning. (I also play guitar for a few minutes right before hitting the sack.)

I can’t quantify how much my darkened room contributes to keeping my weight down, but I fall asleep easily, almost always stay asleep all night and usually wake up in the morning refreshed and eager to get the day started.