Because losing weight isn't solely based on food, other external factors have a significant impact on the structure and function of our bodies.
According to a new study, something as simple as turning off the lights could help you to shed some pounds (or at least prevent you from gaining more).
Scientists believe that light at night, including street lights or smartphones, is making us heavier, according to the Daily Mail.
Sander Kooijman from the Leiden University Medical Center in the Netherlands, along with his colleagues, said that weight gain is increasingly common in today's fast-paced global economy because prolonged artificial light exposure actually inhibits the fat-burning processes that normally occur during darkness, Healthline.com reported.
"The modern 24-hour economy necessitates work at night and shifts social activities to the dark hours," study co-author Patrick C. N. Rensen explained. "Our observations may implicate, assuming the data could be extrapolated to humans, that the current obesity epidemic is at least partly due to increased light pollution."
Researchers exposed one group of mice to light for 24 hours a day for five weeks straight, and found that mice exposed to more light put on 50 percent more fat than those who kept more normal day/night hours and were exposed to only 12 hours of light.
Both groups of mice ate the same amount of food during the experiment and had the same amount of exercise, the Daily Mail reported.
Exposure to light during "normal" sleeping hours disrupts the calorie-burning process, and confuses the body, which makes it adapt to prolonged light exposure by reducing its normal fat-burning rate. Unburned calories then turn into unhealthy, stored fat.
Believe it or not, the routine task of checking your email for less than a minute is enough to throw off the body's internal clock, or circadian rhythm, as well as its metabolism.
This isn't the first study to link artificial lighting - any light that isn't from the sun, such as TVs, computer screens, street lights or lamps - with weight gain.
Previous studies (that also used mice) revealed that mice fed low-fat diets but that were exposed to artificial light for prolonged periods of time actually gained more weight than those fed a high-fat diet, according to a study featured in the journal the Federation of American Societies for Experimental Biology.
"Restricting work and activities to daytime and sleeping in a dark bedroom may help prevent weight gain," Rensen said. "I think it would be really helpful to maintain the biological rhythms as much as possible, by at least sleeping in a darkened bedroom."
Richard Stevens, a breast cancer researcher from the U.S., echoed Rensen's sentiments, and said, "The importance of sleep has finally entered mainstream thinking and practice; however the importance of dark is still greatly under-appreciated."
The study was published May 11 in the journal Proceedings of the National Academy of Sciences.
