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How to Beat Jetlag by Fasting


TPG contributor Katharine Gammon is a science writer for publications including WIRED, Popular Science and Los Angeles Magazine. When she’s not jetting to international conferences to interview some of the world’s leading scientific minds, she’s globetrotting herself, exploring unique destinations including recent trips to New Zealand and Southeast Asia. Today she writes about the science of jet lag and an innovative new method (with roots in human evolution) for combating it.

Summer is one of the most exciting travel seasons. But whether it’s lounging in sunny Mexico or exploring the Far East, travel comes with a not-so-pleasant side effect: jet lag.

Don’t start stocking up on the Ambien just yet, though. Clifford Saper of Harvard University’s Neuroscience Department may have found a way to speed up the body’s adjustment to a new time zone. It all has to do with circadian rhythms – those internal “clocks” in our brain, liver, heart and other tissues that regulate the body’s wakefulness, among other things. These circadian clocks are coordinated by a tiny cluster of cells in the brain called the pineal gland, which is highly sensitive to light and dark. When you move quickly across time zones, the body’s clock gets out of whack, making you feel zonked (the technical term, I swear) when you arrive at your destination.

Getting right to sleep on those long-haul flights can be key to avoiding jetlag once you arrive in your destination.

However, there is a cycle that’s even stronger than this light-based schedule enforcer. Saper had been working with animal sleep cycles, keeping nocturnal animals like rats active during the day. “Scientists have known since the 1920’s that if you took an animal and only allowed it to eat while it was supposed to be asleep, it would switch its cycle,” he explains. This makes sense for evolution – if an animal suddenly was faced with a shortage of its food, and needed to hunt during normal sleep hours, it would be beneficial to flip its schedule for survival.

His research led him to a particular hypothesis: If people also were to eat at the time that’s appropriate for the time in the place they plan to arrive instead of the place they’re leaving, they might also show this effect. For that to happen, he suggests that people fast while on the plane trip. “The thing about the feeding clock is that it supersedes the regular clock in the brain that is driven by light,” says Saper. “So the light cycle remains in the brain, but your body rhythms adjust immediately with the food cycle.”

So basically, by adjusting your eating cycle, you can reset your internal clock faster and more effectively than by adjusting your sleep cycles.

The Paris Paradigm
This is how it would work for a 7-hour flight from New York to Paris:

Fast after breakfast. Most Europe-bound flights are in the evening, so fasting during the day would help your body prepare for its new time zone. You need to fast for about 16 hours for the food-regulators to take over. Granted, a 16-hour fast is an extreme example, but hey, think of all those baguettes and café au laits you’ll enjoy in France once you arrive. Most of all, try not to get “hangry” before your flight because being polite with your other passengers and the flight crew goes a long way.

Avoid caffeine, alcohol or food on the flight. I know, it’s hard to turn away some champagne in business class or a gorgeous meal when you’re on a luxurious vacation. But fasting is the way to make your body reset. If you need to eat something, try to eat fruit and drink lots of water. And sleep as much as you can, Saper advises.

When you arrive at your destination, have breakfast at the appropriate time.  Most flights land in Europe in the morning, so have breakfast when it’s morning in France, and see if your body snaps into that time zone.

No one wants to miss out on their trip because of jetlag.

The Asia Axiom
It’s similar, but a little more complicated for a flight to Asia:

Fast during the day of your flight. You’d need to time your first meal to the morning in Tokyo. Say your flight departs at 3pm from New York (when it is 4am in Tokyo) and arrives at 4pm in Tokyo. To follow the plan, you’d need to fast during day in New York, then try to sleep the first few hours on the flight.

Avoid caffeine, alcohol and food on the flight – until the equivalent of breakfast time at your destination. Since most flights land in the afternoon Tokyo time, you need to have breakfast 6-8 hours ahead of landing. Saper suggests asking the flight attendants to hold your dinner and have it as your breakfast about 6-8 hours ahead of landing time.

Saper’s research on animals was published in 2008 in the journal Science. “It’s kind of interesting that there are hundreds of papers on the phenomenon in experimental animals, but not one in humans,” muses Saper.

Saper’s research does have some human-based precedents, though. Many travelers, including the military, follow the Argonne Anti-Jet-Lag Diet, which relies on a similar fasting and feeding program. Developed by a biologist at the Argonne National Laboratory outside Chicago, the diet alternates two days of moderate pre-departure feasting with two days of fasting — feast, fast, feast, fast — with the second fast on the travel day. A study of U.S. National Guard troops headed to or returning from South Korea showed that those who followed the diet experienced less jet lag than those who didn’t follow it.

As for artificial aids and alcohol, being in a plane is like being in a high mountain town, so alcohol can be particularly potent – and not helpful to recovering from jet lag. Ditto for sedatives and sleeping pills, which can foul up internal clocks and take longer to metabolize. Though fasting seems like it would be a pre-trip hardship, if you’re on a quick trip where you’re looking to make the most of your time on the ground, perhaps a little pre-journey abstention is worth not waking up at 4am and losing a day to grogginess.

Good luck traveling, and let us know if anyone has tried the fasting method!

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