Good news for night shift workers and those suffering from jet lags: Fasting for an average of 14 hours can help you quickly reset your sleep-wake cycle, according to a study from Harvard scientists.

We have long known that our circadian rhythm is regulated by our exposure to sunlight. Now researchers have identified a second “food clock”, a mechanism that evolved to make sure we don’t go to sleep when… we should be foraging for food.

This second clock can override the main clock…and it only takes one day to reset!

Simply stop eating for 12-16 hours before you want to be awake.

Once you start eating again, your body will consider the time you break your fast as your new “morning.”

For example, if you want to start waking up at 4:00 am, you should start fasting somewhere between noon and 4 pm the previous day, and don’t eat anything at all until you wake up at 4:00 am. Make sure you eat a nice healthy “breakfast” at that point.

Another example: If you are traveling from Los Angeles to Tokyo, figure out when breakfast is served in Tokyo, and don’t eat for the 12-16 hours before Tokyo’s breakfast time.

In many cases, simply avoiding any food on the plane, and then eating as soon as you land, should help you to adjust — and avoid some of the uncomfortable feelings of jet lag.

(quoting study published in Science)