Fasting may prevent jetlag

A study conducted by Harvard Med School researchers has concluded that a 16-hour fast prior to long-distance travel can cause the brain's circadian clock to reset, beating jetlag:
Normally, the body's natural circadian clock in the brain dictates when to wake, eat and sleep, all in response to light. But it seems a second clock takes over when food is scarce, and manipulating this clock might help travelers adjust to new time zones, they said.

"A period of fasting with no food at all for about 16 hours is enough to engage this new clock," said Dr. Clifford Saper of Harvard Medical School, whose study appears in the journal Science.

He said a person from the United States traveling to Japan must adjust to a 11-hour time change.

"Because the body's clock can only shift a small amount each day, it takes the average person about a week to adjust to the new time zone. And, by then, it's often time to come home," Saper said in a statement.

Link (via /.)


  1. You know, I mis-read that heading as “Farting May Prevent Jetlag” and I went WTF!

  2. An old friend’s technique for adjusting to the time difference between EST and GMT on Detroit – London trips was to arrive in the early am, have a big lunch with several pints, pass out for a long nap and once you sober up get on with the day. This works but it’s like adjusting the body’s clock by throwing it at the wall really hard.

  3. This kind of science article makes me tired. From the next-to-last paragraph:

    “While skipping meals ahead of a long flight or night shift has not been proven to work in humans, it may be worth a try.”

    Do you think it might be worth trying *before* you write the article implying that it works?

    I mean, yeah, the mouse data is suggestive, but a mouse is a tiny nocturnal rodent with a three-year lifespan and a very different metabolism. Extrapolation from mice to humans doesn’t always go smoothly. The cancer researchers had a joke: “if you’ve got cancer, and you’re a mouse, we can help you.”

    It’s as if the science journalism process is designed to filter out science. You feed in what may be a perfectly good, statistically significant, well-controlled study about *mice* at one end, and it comes out as data-free, speculative extrapolation about *humans*. No wonder half of the world can’t tell the difference between the scientific method and pulling things out of your ass.

  4. A 16 hour fast may keep me from getting jetlag, but it will likely increase the possibility of me completely flipping out on the TSA/a ticket agent/an innocent Belgian tourist in the airport and never making it to my destination in the first place.

  5. Definitely seconding #5 here. It’s bad enough that some of the airlines have basically given up on feeding us out of cheapness, but asking me to fast entirely will make me short tempered, irrational, and easily upset.

    Add in fatigue from being up 27+ hrs for a particularly long haul, and if I don’t have a screaming meltdown at customs when they start interrogating me about maple sugar and suggesting it’s a threat to the local ecology because it’s made from tree sap…

    (True story from Australian immigration – but fortunately at the time I was coherent, and was able to calmly point out that, much like cane sugar, the tree sap has to be boiled to death before you can make sugar with it. I also offered her one if she wanted to try it, but she politely declined and waved me through.)

  6. I don’t eat before I travel or when I travel by plane; I’ve also have never had a problem with jetlag. I’m not a mouse, but this little study did make me pause and reconsider my habits.

  7. I use a different technique that I read about on the internets a few years ago. I don’t sleep so much as a wink on long flights. Then, upon arrival, I go to bed at what I’d like to be my bedtime, local time. Finally, I ensure that I’ll have sunlight in the room in the morning, and set an alarm to “help”. I’ve done this a couple times, with great success.

    Sure, I’ll be dead tired, but the feeling at 4 in the afternoon local time is “It’s four in the afternoon, and I’m dead tired” rather than “It feels like 4am, WTF is going on, I want to go to sleep now”.

    There is, however, one caveat. It is vitally important to actually go to bed at what you want to be your bedtime, local time. Upon return from Prague one year, I was very excited to check my email and otherwise catch up with stuff. We arrived home late evening, and I stayed up until 4 in the morning, local time.

    Bad mistake. I’d overshot, effectively setting my Los-Angeles-dwelling self not to Prague time, not to Los Angeles time, but to somewhere in the middle of the Pacific. For the next week and a half, I couldn’t get to sleep before 4am, and slept until mid-afternoon.

  8. Takuan: In Canada, they wouldn’t have cared about most processed foods so they wouldn’t have bothered asking the question in the first place (I’m Canadian, by the way). Instead, they get very very curious about any books being brought into the country – I’ve had customs unpack my bags, REMOVE THE SWORD PACKED ON TOP OF MY BOOKS, and go sorting through my books to make sure I wasn’t smuggling Mein Kamph or furry porn or something into the country. The sword? Not interesting at all…

    Also, I’ve got the benefit of being able to speak English, and flail along passably in French, so I would probably not get stuck in the same situation Jakanski (sp?) got himself into.

    It’s a terrible thing, but as a white, anglo woman of British descent, I’m moderately safe from most officials in Canada and the US, simply because I look boring and don’t have an accent.

  9. Hmmm. After fasting for 16 hours prior to travel are you “allowed” to eat while you travel? Or do you have to fast 16 hours prior to travel and continue to fast while you travel (so you fast for 24+ hours)?

    When I went to Paris, I did not sleep on the flight over. Got there in the AM and was quite tired, ran around Paris for several hours, then took a 4-hour afternoon nap. Felt great the rest of the week. However, coming home I couldn’t sleep (can’t sleep for long periods in airline seats) and after traveling for something like 24 hours, was exhausted getting back to Denver. A week later I’m still feeling the effects of jetlag (more tired that usual, brain not wanting to function all that well).

  10. No way I could fast before flying. Eating is the only thing that keeps me from being nauseous and nervous at the airport.

    Going from Pacific Time -> GMT, I like to arrive early in the morning in Europe, and pretend like I just woke up. I push myself all day to do normal things and go to bed at a what would have been a normal bed time for GMT time. Its a hard and tiring day (nothing a lot of coffee can’t help) but once I hit the mattress that night I sleep like a rock, and wake up feeling pretty normal the next day.

  11. When I go to Germany, I eat and sleep normally before travel, drink lightly on the flight and keep drinking when I hit the ground. Start with the airport lounge, grab one or two for the train ride then drop your stuff off at the hotel, stop to pick up a beer at the front desk (yes, you can get beer anywhere in Germany) on the way up to your room, freshen up, then go out for more beers. You’ll soon be synchronized with local (drinking) time. You can then go back to your hotel with a righteous buzz on and you’ll wake up right on time the next morning to continue your beer explorations. The last time I went to Germany with a drinking buddy, we stayed up for 35 hours.

  12. Hmm. I’ll be flying into Tokyo later this week. I’d like to try this but I don’t know if I’m willing to bet a week of my time on it.

    I’ll most likely go with the tried-and-true sleeping medication method. You book an early flight and set your watch to Tokyo time. When the watch reaches something you would consider a reasonable bedtime, take the medication and do your best to get eight hours of sleep. I’ve had very good luck with this. I’m definitely a little tired the next day, but I’m not jetlagged.

  13. Coming in from London
    From over the pole
    Flying in a big airliner
    Chickens flying everywhere around the plane
    Could we ever feel much finer?

    Coming into Los Angeles
    Bringing in a couple of keys
    Don’t touch my bags if you please
    Mister Customs Man

    There’s a guy with a ticket to Mexico
    No, he couldn’t look much stranger
    Walking in the hall with his things and all
    Smiling, said he was the Lone Ranger


    Hip woman walking on a moving floor
    Tripping on the escalator
    There’s a man in the line
    And she’s blowing his mind
    Thinking that he’s already made her


    Coming in from London
    From over the pole
    Flying in a big airliner
    Chickens flying everywhere around the plane
    Could we ever feel much finer?

  14. I’d like to be the first name on the list of commenters who would prefer 2 days of jetlag to 16 hours of fasting ANY DAY.

    Although I must admit I probably have it easier than most: Rome time to Boston time is 6 hrs even and the trip, if direct isn’t much longer. 3 pints with dinner and staying up until it’s dark out is usually all I need to wake up at a normal local morning hour.

    Maybe this fasting trick is a lot more useful for trans-Pacific voyages where the daylight screws with you more?

  15. hmm. interesting. I tend to forget to eat for extended periods of time… and I have a sleep disorder (DSPS) that resembles permanent jet lag… wonder if there’s any connection.

  16. My cure for jetlag: Suck it up, creampuff.

    Not eating for 16 hours would be more of a pain in the ass than dealing with the jetlag.

  17. Being used to go back and forth France-USA, my trick is to:

    – drink plenty of water (and wine on the plane if you can… it helps to sleep) even if you need to pee a lot.

    – force myself to stay up until the evening upon arrival.

    That way the body is still hydrated and the 1st night sleep is crucial for my system to switch to its new reality. A little sleeping pill or things like Benadryl can help for that 1st night.

    Normally takes me 2-3 days max to be fully adjusted. And… I get to eat the whole time!

  18. besides that, most airline foods are highly salted and made with rancid oils. Definitley something that will make you feel worse than if you eat or not. I completely agree with fasting during any flight.

    Patrick O’Connor, MBA

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