Changing mealtimes to fit your destination before you fly could help to beat jet lag, a study suggests.
Eating times were found to reset a key part of the body clock that is impervious to daylight, suggesting a new weapon to speed up adaptation to a new time zone.
Many parts of the body have their own daily cycles, which are controlled by a “master clock” in the brain. It has long been known that daylight can reset this master clock, but the grogginess caused by flying around the world is thought to be the result of clocks in the rest of the body struggling to catch up.
In the first study of its kind, British scientists studied ten men in the laboratory who slept at the same time and ate the same food but half of whom had their meals delayed by five hours. After six days their routines were switched. The changes did not affect their master clock according to measures such as melatonin cycles. However, blood sugar rhythms were put back by five hours, researchers report in Current Biology.
“We think this is due to changes in clocks in our metabolic tissues, but not the master clock in the brain,” said Jonathon Johnston of the University of Surrey, who led the study.
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Exposure to daylight in a new timezone helps the master clock to adapt, but Dr Johnston said his findings could point the way to minimising the symptoms of jet lag caused by body clocks resetting at different speeds.
Although his study was not conclusive, he said the results of suggested a regime to minimise the symptoms of flying around the world. “If you’re flying west, [a few days before] you might want to change not only your light exposure but also to start delaying mealtimes by a couple of hours.”
Recipe for a happy landing
Daylight Flying west, exposure to blue light early in the evening will help to delay your body clock
Melatonin A hormone available as a food supplement in the US but more tightly regulated in the UK. The body produces it at night, so taking it in the evening moves the body clock forward when flying east
Meal times Eat earlier if flying east and later if flying west