I travel a lot for work – most recently to New Zealand – and although I love it, I have always struggled with jet-lag. Then a few years ago I discovered the joys of intermittent fasting and not only did I lose weight, but I found that my jet-lag was greatly improved.
Last week a woman called Sarah contacted me to say she’d experienced the same. Was the 5:2 responsible, she asked, and if so, why?
Surprisingly, there is indeed a link between intermittent fasting and jet-lag – a relationship first noticed in the 1980s by Dr Charles Ehret, a researcher at the University of Chicago.
Jet-lag has been a subject of interest to me recently, having returned from a work trip to New Zealand which forced my body clock to adapt rapidly.
Jet-lag, caused by the imbalance between your internal body clock and your new time zone, can be awful, with symptoms including insomnia, hunger, irritability, constipation or diarrhoea.
If you have flown from the UK to Sydney, for example, your body clock will tell your brain it is 10pm and time for bed, while everyone around you is eating lunch. It takes about a day to adjust to each time zone you move through, so if flying to Sydney, it can take a week.
Reset your clock
Dr Ehret suggested that you could reset your internal clock much faster if, for three days before flying, you alternate feasting and fasting.
On the one ‘feast’ day, he recommended a protein rich breakfast, an above average-sized lunch and a carbohydrate-heavy dinner. On the two, ‘fast’ days, he suggested eating just 800 calories. Ehret coined this the ‘Argonne Diet’.
So does it work?
Two years ago, the US military put the Argonne Diet to the test when 186 soldiers travelling to South Korea were split into two groups; feasting-fasting, and eating normally.
Those who tried the Argonne Diet were seven and a half times less likely to experience serious jet-lag than those who ate normally. The exact reason why this works remains unknown, but I suspect it resets the healthy bacteria inside your gut that influence the body in many unexpected ways. If any of you give this a go, do write and tell me how you get on.
How to do the Argonne Diet
Start three days before you fly. On day one, a FAST day, restrict calories to 800. You can find suitable recipes in the 8-Week Blood Sugar diet book, or on this website.
On day two, FEAST; eat a high-protein breakfast, an above-average-size lunch and a high-carbohydrate dinner and don’t drink coffee after 5pm.
Repeat the ‘FAST’ instructions for day three.
On the day of flying, eat at the breakfast time of your destination and do not drink alcohol on the plane. On long flights, try eating and sleeping at the same time as your destination while on the plane.
The power of light
Using bright light to combat jet-lag can be effective when the light shines at certain times of the day.
I would recommend using Entrain, a free app that suggests exact times you should be exposed to light.
I keep it simple. When heading to New York – five hours ahead of the UK – I put myself on New York time before flying. I delay breakfast until 8am New York time (1pm here), skip lunch and have a snack at about 7pm (midnight here). I go to bed at a normal time.
Next morning I get up early, grab some morning light and find that my body clock is well and truly reset.