It’s not just about what you eat, but when.

By Amy Farley
May 27, 2014
Tired opening refrigerator
Credit: Getty Images

Even more than foreign-transaction fees and data-roaming charges, jet lag is the bane of international travelers. Resetting your internal clock to a new time zone can be a days-long process. Fortunately, there are ways to ease yourself onto a new schedule—and what you eat and drink can play a key role.

First and foremost, say nutritionists and dietitians, is the matter of hydration. “When you’re dehydrated, you are irritable, tired, and weak,” says Bonnie Taub-Dix, a New York–based registered dietitian and author of Read It Before You Eat It.

To avoid compounding the effects of crossing time zones, drink plenty of water, 100 percent fruit juice, or herbal tea while you’re in transit—and even before you depart. Taub-Dix advises travelers to plan ahead, avoiding salty food (in favor of water-rich fruits and vegetables) and drinking water well in advance of a flight. Caffeine and alcohol (sadly) are also inadvisable while flying. Both are dehydrating and can disrupt sleep—even alcohol, which acts as a stimulant a few hours after you consume it. Studies show that although it may initially help put you to sleep, the quality of your rest will be poor. The same is true for heavy, high-fat meals, Taub-Dix says. They’re difficult to digest and may lead to a restless night.

Once you’ve arrived, it’s equally important to be mindful of your meals, especially if you find yourself dragging, according to Angela Lemond, a Dallas-based registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics. “Sleep deprivation messes up your feelings of hunger and satiety. So you’re more at risk to compensate by overeating,” she says.

This will only exacerbate the problem, however. To keep your energy levels steady, opt for lighter meals with a good balance of protein, complex carbohydrates, and plant-based foods. And make sure to have protein-rich snacks on hand, especially if you’re traveling to areas where such foods are hard to find: nuts, peanut or almond butter with whole-grain bread or crackers, cheese, yogurt, or easy-to-pack protein bars.

But in many ways, overcoming jet lag is as much about when you eat as what you consume. Studies suggest that the body’s natural circadian rhythm is tuned to light and, crucially, food. There’s even some evidence that our food-based circadian clock can actually override the more widely recognized light-based one. A recent experiment involving mice at Boston’s Beth Israel Deaconess Medical Center revealed, in rodents at least, the presence of a food-related clock that can be manipulated with fasts. In this study, a 16-hour fast was enough to throw off the animals’ light-based cycles and turn them into night owls.

For those of us unwilling to go to such extremes, there’s the Argonne Anti-Jet-Lag Diet, developed in the late 1970’s by biologist Charles Ehret, who worked at the Department of Energy’s Argonne National Laboratory in Illinois. Ehret prescribed a four-day cycle of feasting and fasting to help break the body’s circadian rhythm before landing in anew time zone. His ideas caught on and, by the 80’s, the diet’s adherents included members of the military, athletes, professional musicians, and even Ronald Reagan. Ehret later collaborated with Bill Ashton to create Stop Jet Lag, a service that provides customized plans for travelers that regulate light, sleep, and meals. Most of these plans begin with a modified, less draconian version of Ehret’s feast-fast cycle, counseling large- and light-meal days instead.

Stop Jet Lag’s plans vary according to traveler and itinerary, but Ashton says there are a few general rules when it comes to meals. The most important is to think about your diet at least 12 hours in advance of what will be your first morning in the new time zone (which could be on the plane). Plan to have a light meal around that time and then let your blood-sugar levels steadily drop, more or less mimicking what happens during sleep.

On an overnight flight from New York to Heathrow, for example, this would mean skipping the in-flight dinner that’s served at about midnight, London time. Better to focus on rest. Follow up with a protein-heavy “breakfast” according to your new time zone, which will signal your body that you’re now on a different schedule. This may mean breakfasting while the rest of the plane is sleeping. Ashton advises packing your own food, or asking the flight attendant to set aside a meal for you, even if it’s not what you’d traditionally associate with breakfast.

Though there haven’t been enough studies to say definitively if this plan works, the basic principles resonate. “Mealtime is a natural synchronizer,” Lemond says. “The more you can mimic where you’re going before you leave, the better off you’ll be.”