Artificial Lights Linked To Higher Rates Of Obesity

By Lisa Rapaport

Reuters Health - Obesity rates may surge in places where artificial lights blaze all night compared to communities where people tend to live in darkness after the sun goes down, a recent study suggests.

To explore this connection, researchers analyzed U.S. military satellite images of nighttime illumination around the globe and country-level data from the World Health Organization (WHO) on the prevalence of overweight and obese people.

Artificial light at night contributed to excessive weight in men and women about as much as eating junk food, the research team reports in the International Journal of Obesity.

“Because of artificial light at night, we often eat in the wrong time, that is, after the natural dusk, when metabolic processes slow down,” said N.A. Rybnikova of the University of Haifa in Israel.

The study doesn’t prove light bulbs cause obesity, and scientists aren’t yet certain how lamps or the glow from gadgets like tablets and televisions might influence how much people weigh, researchers caution.

But it’s possible artificial light might contribute to obesity by suppressing the production of melatonin, a hormone that helps regulate sleep cycles.

These lights may also contribute to what’s known as social jet lag, or disruption of the body’s natural circadian rhythms that happens when people sleep and wake at times that are at odds with their internal biological clocks.

For women and men, higher birth rates appear to be one of the stronger predictors of excess weight and obesity.

Urbanization, as well as calorie intake of oils, fats and carbohydrates also appear to predict excessive weight in men and women alike. Consuming more roots and tubers was linked to a lower likelihood of excessive weight, the study also found.

Together with variables like eating habits and exercise levels, nighttime light explains up to about 73 percent of the variation in rates of excess weight —> Read More

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