Content hub Articles and recipes How to reset your body clock Body clock disruption happens for all sorts of reasons, but research suggests diet could make all the difference. If you’ve struggled to sleep after a shift, or travelled abroad only to find yourself twiddling your thumbs for half the night, then you have probably suffered from ‘desynchronosis’. More commonly known as ‘jet lag’, this annoying phenomenon, which can cause a range of symptoms from poor energy levels to constipation, is triggered by disruption to the body’s internal clock, or ‘circadian rhythm’. And we don’t even have to cross time zones to experience it — changes in sleep and meal patterns are enough to cause circadian disruption. There are, however, some things we can do to ease the impact. Eat meals at the same time everyone else does in the new time zone, not when you feel hungry. Food, just like daylight, helps reset your internal clock It takes time According to experts, the time it takes for the body clock to adjust can depend upon whether we are suddenly having to go to bed ‘earlier’ or ‘later’ — and by how many hours. In general, the human body clock is thought to be able to adjust by about one hour a day. Hence, in Why We Sleep, neuroscientist Matthew Walker explains that if you’re flying to a time zone eight hours ahead, expect it to take eight days to adjust. Changing your body clock Our destination when travelling — whether east or west — also makes a difference; and in terms of working shifts, equates to whether you have to go to bed earlier or later. Because the human body clock is slightly longer than 24 hours, it is thought to be easier for us to stay up late than go to bed early. What this means for travel is that if you’ve landed in a country at bed time, but your body clock is still only ready for lunch, you’ll struggle to sleep, whereas heading west and staying up later may be a bit easier. Gradually changing your sleep routine before travel can help to reduce the impact of jet lag. The NHS says to get plenty of rest ahead of travel, and you could even start going to bed and waking up an hour or two earlier (or later) than usual. Shifting meal times, if possible, can also help. Speaking to Optimum Nutrition, Walker said: “Set your phone, watch and computer to the destination time as soon as you get on the plane. “Once in the new time zone, get as much natural daylight early in the morning, and avoid it in the evening (including from electronics). “Eat meals at the same time everyone else does in the new time zone, not when you feel hungry. Food, just like daylight, helps reset your internal clock.” Prebiotics and dietary fibre There is also evidence to suggest that whether we’re changing time zones or a shift pattern, feeding our gut bacteria can add a level of resilience. According to the findings of a recent US study on rats, dietary fibre called prebiotics may help to aid recovery when the body clock gets knocked out of sync. Previous research carried out by the same team had already found that rats raised on prebiotic-infused food slept better and were more resilient to some of the physical effects of acute stress. In this latest study, funded by the US Office of Naval Research, it was discovered that prebiotics, which pass through the small intestine to become food for gut bacteria, also promote resilience to body clock disruptors. In a human context, this could mean protection against the effects of jet lag, shift work or lack of natural day light. During the study, rats were raised on either regular food or food enriched with two prebiotics: galactooligosaccharides and polydextrose. The rats’ light-dark cycle was then manipulated, weekly, for eight weeks — the equivalent of travelling to a time zone 12 hours ahead every week for two months. By the end of the study, it was found that the prebiotic-fed rats realigned their sleep-wake cycles and core body temperature (which can also be thrown off when internal body clocks are out) more easily. They were also more resistant to gut bacteria changes that often come with stress. “This is one of the first studies to connect consuming prebiotics to specific bacterial changes that not only affect sleep but also the body’s response to circadian rhythm disruption,” said Thompson. An abundance of several “health-promoting” microbes was also found in the guts of the prebiotic-fed rats. These included Ruminiclostridium 5, associated in other studies with less fragmented sleep; and Parabacteroides distasonis, which was found to produce metabolites that protected rats from jet lag-type effects. What to eat for jet lag Prebiotics are found in the fibre of foods such as Jerusalem artichokes, garlic, leeks, onions, under-ripe bananas, chicory root, and resistant starch — the latter of which is formed when starchy carbohydrates are chilled and reheated. They can also be found in some supplements. However, whilst the authors said it’s not impossible that loading up on naturally prebiotic rich foods might help to keep human body clocks running on time, the rats had been fed in human terms “excessive” amounts of prebiotics. Corresponding author Monika Fleshner said: “If you are happy and healthy and in balance, you do not need to go and ingest a bunch of stuff with a prebiotic in it. “But if you know you are going to come into a challenge, you could take a look at some of the prebiotics that are available. Just realise that they are not customised yet, so it might work for you but it won’t work for your neighbour.” What to do: Change your sleep routine and mealtimes before your travel. Follow the patterns of the locals once you're there. Get a good amount of prebiotic dietary fibre. Enjoyed this article? Learn why sleep is oh so important For articles and recipes subscribe to Optimum Nutrition Discover our courses in nutrition Manage Cookie Preferences