‘Social jet lag’ causing sleep loss tied to obesity

'Social jet lag' may be making people fat.

A lack of sleep and irregular work patterns have shown to be out of sync with our natural circadian rhythm, possibly causing obesity, says a new study.

Social jet lag is "the discrepancy between what our body clock wants us to do and what our social clock wants us to do," says Till Roenneberg, of the University of Munich's Institute of Medical Psychology, reported CNN.

"It almost looks as if people on a Friday evening fly from Paris to New York, and on Monday morning they fly back again."

The study looked at questionnaires completed by 6,500 people from central Europe regarding their sleep habits.

The researchers found that those who disrupted their biologoical rhythms were more likely to become overweight and to drink and smoke said ABC News.

"Beyond sleep duration, social jet lag is associated with increased body mass index," said Roenneberg, reported CBC News.

"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."

Critics said that causation is still not proven as those who are obese might have different rhythms due to their obesity not vice versa.

"Are obese people more likely to be shifted against the normal tendency of their internal clock or does the shifting lead to obesity as the authors suggest?" asked Dr. Elliott Lee, a sleep specialist at the Royal Ottawa Health Care Group, reported CBC News.

The research is found in the journal Current Biology.