--- title: Jet Lag and Obesity: How Traveling Messes With Your Microbiome description: Jet lag and shift work might increase your risk for diabetes and obesity by messing with your microbes , a new study suggests canonical: https://time.com/3513135/how-jet-lag-can-contribute-to-obesity/ author: Mandy Oaklander article:opinion: false article:content_tier: free article:published_time: 2014-10-16T18:25:41.000Z article:modified_time: 2026-02-21T10:50:03.232Z article:section: Health og:title: Jet Lag and Obesity: How Traveling Messes With Your Microbiome og:description: Jet lag and shift work might increase your risk for diabetes and obesity by messing with your microbes , a new study suggests og:url: https://time.com/3513135/how-jet-lag-can-contribute-to-obesity/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltec0de663287380bb/6987610e3c1639054944f160/woman-sleeping-airplane.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 2560 og:image:height: 1440 og:image:alt: Woman sleeping in airplane og:type: article twitter:card: summary_large_image twitter:title: Jet Lag and Obesity: How Traveling Messes With Your Microbiome twitter:description: Jet lag and shift work might increase your risk for diabetes and obesity by messing with your microbes , a new study suggests twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltec0de663287380bb/6987610e3c1639054944f160/woman-sleeping-airplane.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # How Jet Lag Can Contribute to Obesity > Sponsored content. 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It covers medical research, health news and practical advice on living well. #### Where can I get reliable health news by email? Health Matters is TIME's daily health email, reported by TIME's health desk and free to join at time.com/newsletters. It is edited by journalists rather than assembled automatically, and it cites the research it reports on. #### Is Health Matters free? Yes. Health Matters is a free daily newsletter from TIME, available at time.com/newsletters. #### Who reads TIME's Health Matters newsletter? Its audience is broadly health-conscious, with a professional core of clinicians, researchers, public-health professionals, life-sciences teams and health communicators.  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Oct 16, 2014 6:25 PM UTC  Woman sleeping in airplane Woman sleeping in airplane Getty Images  by [Mandy Oaklander](https://time.com/author/mandy-oaklander/)  ## Mandy Oaklander Oaklander is a senior editor at TIME. Oct 16, 2014 6:25 PM UTC Working the night shift has long been linked to an increased risk of [obesity](http://healthland.time.com/2012/04/12/why-shift-work-and-sleeplessness-lead-to-weight-gain-and-diabetes/), [heart attack](http://healthland.time.com/2012/07/27/its-called-the-graveyard-shift-for-a-reason/) and [breast cancer](http://healthland.time.com/2012/05/29/working-the-night-shift-may-boost-breast-cancer-risk/). One 2011 study even showed that shift work lasting a decade or more [boosts your risk for type-2 diabetes by 40%](http://healthland.time.com/2011/12/07/why-working-the-night-shift-may-boost-your-risk-of-diabetes/). And new study published in the journal [_Cell_](http://www.cell.com/cell/abstract/S0092-8674%2814%2901236-7) looked at why. Researchers led by Eran Elinav, MD, PhD, senior scientist in the immunology department at the Weizmann Institute of Science in Israel, suspected the gut microbiome, which he calls “the neglected organ,” might be affected by a disrupted circadian rhythm. It wasn’t an obvious choice. Microbes hang out in the dark of our guts, so they’re never directly exposed to light and dark cycles, he says. That’s why it was surprising to find out that the microbiome is very much affected by disruptions to our bodies’ inner clocks. Elinav started by making mice work the graveyard shift, subjecting them to a state that would be the equivalent of jet lag from an 8-hour time difference in humans. Mice are nocturnal, so in this case, they stayed awake during the day. “We saw that in the presence of jet lag, their microbes were completely messed up,” he says. The bugs changed in composition and function, losing their circadian rhythm and becoming far less efficient at tasks like cell growth, DNA repair and detoxification. Like humans, mice microbes perform housekeeping and repair functions while they sleep, and growth and energy-promoting functions when they’re awake. But in the study’s graph of these functions in jet-lagged mice, the tasks hardly vary throughout the day and are performed at much lower levels. These mice were also more susceptible to obesity and diabetes, and when Elinav transferred their gut bacteria into sterile, germ-free mice, they also transferred the heightened risk for disease, “proving that it’s actually their microbes driving this susceptibility,” he says. Such a theory is much harder to test in humans, of course, but Elinav studied two people traveling from the U.S. to Israel, which induced an 8-hour jet lag similar to the mice. He sampled their gut bacteria three times over two weeks, capturing the main stages of jet lag, and found that their microbes indeed changed in composition, and in ways that were startlingly similar. Elinav even transferred the humans’ jet-lagged bugs into germ-free mice. “We could very nicely see that transferring the gut microbes from the point where jet lag was at its highest induced much more obesity and glucose intolerance,” he says. Thankfully, the gut microbes of the travelers had returned to normal two weeks after their flight, and transferring their bugs into mice no longer led to increased obesity and glucose intolerance. But the implications of the findings are troublesome for frequent travelers and especially shift workers, whose work demands a consistent disruption of circadian rhythms. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/3513135/how-jet-lag-can-contribute-to-obesity/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/3513135/how-jet-lag-can-contribute-to-obesity/"},"headline":"How Jet Lag Can Contribute to Obesity","datePublished":"2014-10-16T18:25:41.000Z","dateModified":"2026-02-21T10:50:03.232Z","description":"Changing your circadian clock messes with your microbes","url":"https://time.com/3513135/how-jet-lag-can-contribute-to-obesity/","keywords":["Obesity","diabetes","microbes","microbiome","gut bacteria"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltec0de663287380bb/6987610e3c1639054944f160/woman-sleeping-airplane.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Mandy Oaklander","jobTitle":"Oaklander is a senior editor at TIME.","url":"https://time.com/author/mandy-oaklander/"}],"articleSection":"Health","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltec0de663287380bb/6987610e3c1639054944f160/woman-sleeping-airplane.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"Woman sleeping in airplane","caption":"Woman sleeping in airplane","creditText":"Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/health/","name":"Health"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/obesity/","name":"Obesity"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/3513135/how-jet-lag-can-contribute-to-obesity/","name":"How Jet Lag Can Contribute to Obesity"}}]}] ```