Social jet lag boosts obesity risk

A wide difference between natural wake up time and the time alarm clock rings every day may significantly raise our risk of obesity, say researchers. A European study warns that the frequent mismatch between our natural wake up time and daily schedule forced by modern life has led to a widespread “social jet lag” which threatens the health of millions of people worldwide. The report in journal Current Biology was a result of a study by researchers in Germany who analyzed sleep, height, weight, age and sex data submitted by 65,000 European people. The finding reveals that the weekly sleep disruption is more than just a nuisance and has a significant association with higher obesity risk. “Beyond sleep duration, social jet lag is associated with increased body mass index (BMI),” a measure of overweight and obesity, wrote Till Roenneberg and colleagues from the university of Munich. “It is thought the majority of the population is working the early shift. Here, we identify this discrepancy between biological and social timing as one of many factors contributing to the epidemic of overweight and obesity.” “With social jet lag, we're forced to eat at times when the body doesn't want to eat, or isn't prepared for digesting food properly,” Roenneberg says. “All these things coming together might influence the way you digest food and how you incorporate it into your body fat. The result is that you become overweight or obese.” Moreover, the overweight people who had a wider gap between their weekday and weekend “time zones” were more likely to have a higher BMI and obesity risk, warned the study. “Living against our body clocks is detrimental for our health," says Roenneberg who urged people to pay more attention to their body’s natural rhythm than just job and economy. “On an epidemiological level, we pay an enormous price for not being within our natural clocks.”