How to Naturally Reset Your Sleep Cycle in One Night

By Will Chen on 31 July 2009 107 comments

Not eating for 12-16 hours can help people quickly reset their sleep-wake cycle, according to a study from the Harvard Medical School. This discovery can drastically improve a person's ability to cope with jet lag or adjust to working late shifts. (See also: Tips for Sounder Sleep at Hotels)

Scientists have long known that our circadian rhythm is regulated by our exposure to light. Now they have found a second "food clock" that takes over when we are hungry. This mechanism probably evolved to make sure starving mammals don't go to sleep when they should be foraging for food.

The lead researcher Clifford Saper explains:

The neat thing about this second clock is that it can override the main clock...and you should just flip into that new time zone in one day.

It usually takes people a week to fully adjust to a new time zone or sleeping schedule. To think that this new "food clock" hack can help you change your internal clock in one day is mind boggling.

How Do You Use This Trick?

Simply stop eating during the 12-16 hour period before you want to be awake. Once you start eating again, your internal clock will be reset as though it is the start of a new day. Your body will consider the time you break your fast as your new "morning."

For example, if you want to start waking up at 2:00 am, you should start fasting between 10:00 am or 2:00 pm the previous day, and don't break your fast until you wake up at 2:00 am. Make sure you eat a nice healthy meal to jumpstart your system.

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.

Combined with other hacks to help you get more sleep and be more productive, you can quickly adjust to any time zone.

The Science: Why Does This Work?

Like everything else in our evolutionary history, it has to do with survival. Clifford Saper explains:

Here's a quick summary of Saper's research findings:

"For a small mammal, finding food on a daily basis is a critical mission. Even a few days of starvation, a common threat in natural environments, may result in death," the study said.

"Hence, it is adaptive for animals to have a secondary "master clock" that can allow the animal to switch its behavioral patterns rapidly after a period of starvation to maximize the opportunity of finding food sources at the same time on following days."

The shift is a survival mechanism in small mammals that forces them to change their sleeping patterns, Fuller suggests. One starvation cycle is enough to override the traditional light-based circadian clock, the study suggests.

"This new timepiece enables animals to switch their sleep and wake schedules in order to maximize their opportunity of finding food."

"A period of fasting with no food at all for about 16 hours is enough to engage this new clock," says Saper.

"So, in this case, 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." CBC (quoting study published in the May 22 issue of Science)."

Like this article? Pin it!


How to Naturally Reset Your Sleep Cycle in One Night

How to Naturally Reset Your Sleep Cycle in One Night

Average: 3.9 (72 votes)
Your rating: None

Disclaimer: The links and mentions on this site may be affiliate links. But they do not affect the actual opinions and recommendations of the authors.

Wise Bread is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

Guest's picture

As I am a Muslim and I fast during the month of Ramadan, I discovered the relationship between fasting and sleep pattern changes myself, later I searched the web and found many articles on it. This method certainly works. Today I am fasting for 16 hours to adjust sleep timing, I shall report the results.

Guest's picture
mebing lapung

Let me try it first...then I will give my opinion...i wish it works!!!

Guest's picture

If I go too long without eating before bed I cannot sleep good and have terrible stomach upset. It would be wise to eat plenty just before it is time to start the fast.

Guest's picture

Its been a month i actually realized it myself sleep cycle has something to do with food. So last night i slept for 5 hours only and stayed awake. I slept literally while sitting in evening for a min. I was pretty sure after dinner i will fall asleep. So i was hell tired and sleepy, took dinner, had a cup of milk at 9pm. Now here I am searching and commenting. My sleep cycle starts at 2am. So 1 more hour to wait.definitely gonna try it.

Guest's picture
Guest Christine

This makes sense and anything is worth a try as I have had chronic insomnia for 16 years and absolutely nothing makes a difference but why is part of my previous treatment that I never go to sleep hungry as low blood sugar will make me wake up? So much conflicting advice.

Guest's picture

I have a question. Is it mandatory to sleep during the 16 hour fasting period? or can you stay awake during the fasting period? Will it work even if your awake?

Guest's picture

If I was to do this, but I needed to eat something in those hours, would I be able to have a snack? Would I also be able to drink water? I am changing my sleep schedule for my new job at a dairy farm and will be going to be about 6:00pm, and waking up about 1:00am. I want to be make sure I will be able to do this.