Going somewhere far this summer? Vacation and business travelers can reduce or avoid jet lag with the so-called Anti-Jet-Lag Diet developed at the U.S. Department of Energy's Argonne National Laboratory.

Invented by Charles Ehret, a biologist whose career was devoted to the study of daily biological rhythms, the diet has helped hundreds of thousands of travelers.

A study found that travelers who follow this diet are seven times less likely to experience jet lag when traveling west and 16 times less likely when traveling east.

"Anyone traveling across three or more time zones can use the Argonne Anti-Jet-Lag Diet to eliminate or reduce jet lag," said Argonne's Dave Baurac. "The Argonne Anti-Jet-Lag Diet uses the same natural time cues that nature uses to maintain our healthy cellular rhythms, such as meal contents and timing, light and dark cycles and daily activity cycles."

Jet lag's irritability, insomnia, indigestion and general disorientation are symptoms of the body's inner clock being out of step with meal times, sunrise and sunset, and daily cycles of rest and activity.

The Anti-Jet-Lag Diet uses some of these same time cues to fight jet lag. It consists of a coordinated plan that combines a number of time-giving cues — including alternate days of moderate feasting and fasting — to help you adjust to a new schedule.

What you eat is the key because eating sends your body signals about waking up and going to sleep. And because meals tend to occur at reasonably consistent times during the day, their regularity helps to reinforce the regularity of other time-setting activities.

You need to start the diet a few days ahead of your departure by carefully planning the amounts and types of food you will eat at meal times. On the day you arrive at your destination, your body's clock is reset by assuming the same meal and activity schedule as people in the new time zone.

For example, suppose you are planning a Sunday flight from New York to Paris — a nine-hour flight across six time zones. Your flight arrives Monday at 10 a.m. Paris time. So, you want to advance your body clock so it is not still set for 4 a.m. New York time upon arrival.

You begin the diet on Thursday, three days before the flight. You eat your meals at their regular New York times. According to the diet, Thursday is a feast day, to be followed by fasting (not really fasting, but lower consumption) on Friday, feasting on Saturday and fasting on Sunday. The day of the flight is always a fast day. On feast days, you eat three full meals. Take second helpings. Breakfast and lunch should be high in protein. Steak and eggs make a good breakfast, followed later by meat and, perhaps, beans for lunch. High-protein meals should be mostly, but not necessarily exclusively, protein.

Dinner is high in carbohydrates. These help the body produce chemicals that it normally produces when its time to bring on sleep. Pasta is good, but no meat — they contain too much protein.

On fast days, eat three small meals. They should be low in carbohydrates and calories to help deplete the liver's store of carbohydrates. Acceptable meals on fast days would contain 700 calories or less and might consist of skimpy salads, thin soups and half-slices of bread.

Whether feasting or fasting, you must drink coffee, or any other drink containing caffeine, only between 3 p.m. and 5 p.m. This is the one time of day when caffeine seems to have no effect on the body's rhythms. Sunday evening — flight day — you board the plane about 7 p.m. and begin the first phase of speeding up your body's internal clock to Paris time. Drink two or three cups of coffee between 9 and 10 p.m., turn off the overhead light and go to sleep.

About 1:30 a.m. New York time, you take the final steps that reset your body's clock to Paris time: You begin a third feast day, but this one is based on Paris time. It may be 1:30 a.m. in New York, but in Paris it's 7:30 a.m. — your normal breakfast time. You wake up — the coffee you drank before going to sleep helps you do this — and eat a high-protein breakfast without coffee; it might be last night's supper, which you saved for breakfast. Most airlines will gladly agree to this request. The large, high-protein meal helps your body wake up and synchronize itself with the Parisians, who are eating breakfast at about the same time.

Having finished breakfast, you need to stay active to keep your body working on Paris time. The other passengers may be asleep, but you are walking the aisles, talking to the flight attendants or working at your seat.

Monday afternoon in Paris, a few hours after your arrival, eat a high-protein lunch. Steak is a good choice. That evening, eat a high-carbohydrate supper — crepes, for example, but with no high-protein meat filling — and go to bed early.

Tuesday morning, you wake up with little or no jet lag.

Free information about the Argonne Anti-Jet-Lag Diet and how to tailor it to your next flight is online at http://www.AntiJetLagDiet.com