The current scientific theory is that sleep and wake cycles are entrained by light, via the retina, activating pathways in the suprachiasmatic nuclei of the hypothalamus. Hence modulation occurs gradually, as per the shifting light availability of the natural seasons, and complete reversals of sleep and wake cycles cannot be achieved solely through light stimulus.
But there is another clock that can override this light-entrained mechanism, ensuring that an animal is awake when food is available given a degree of food scarcity. Sleep patterns are thus entrainable even to extreme differences of cycle, through food reward pathways following food deprivation. Enter lipids....
I have done a lot of long haul international flights, typically between Australia and Europe, some between Australia and the US or Europe and the US, and for most of my life I found that I adjusted fairly easily to the new time zone. In recent years though, it has become trickier. My circadian rhythm seems more set and unwilling to budge. I had also been inclined to work on my academic research late into the night, sleep late of a morning, or not sleep enough. On the whole, I would say that my respect for sleep hygiene and consistency throughout my adult life has been quite woeful.
This became a real problem in my last overseas trip when I spent much of the first week in a completely discombobulated zombie state in London, unable to sleep through the night, and wanting to curl up on a warm fluffy rug when I had instead a cold hard library seat beneath me during the day time. It didn't seem to be getting any better after 4 days and I started to feel a bit desperate. I had not brought any melatonin with me, but in any case had doubts about its bioavailability in supplement form. I tried meditating before bedtime, not eating heavy foods at night, not drinking coffee after midday, doing hypnotic meditations in bed when I could not sleep. I felt lovely and relaxed, present and still. But the new required sleep pattern yet eluded me.
I was studying for a physiology exam in my biomedical science program and actually learning about biological rhythms. It dawned on me suddenly that since there are more and more people travelling across time zones than ever before, there must be some good new scientific research on this exact problem.
Well there is, and it all about food reward. Suddenly, things became extremely interesting...
The article that most peaked my interest was this one, published in Science on May 23 2008. doi:10.1126/science.1153277.
'Differential Rescue of Light- and Food-Entrainable Circadian Rhythms' by Patrick M. Fuller, Jun Lu, and Clifford B. Saper, both in the Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
When food is plentiful, circadian rhythms of animals are powerfully entrained by the light-dark cycle. However, if animals have access to food only during their normal sleep cycle, they will shift most of their circadian rhythms to match the food availability. We studied the basis for entrainment of circadian rhythms by food and light in mice with targeted disruption of the clock gene Bmal1, which lack circadian rhythmicity. Injection of a viral vector containing the Bmal1 gene into the suprachiasmatic nuclei of the hypothalamus restored light-entrainable, but not food-entrainable, circadian rhythms. In contrast, restoration of the Bmal1 gene only in the dorsomedial hypothalamic nucleus restored the ability of animals to entrain to food but not to light. These results demonstrate that the dorsomedial hypothalamus contains a Bmal1-based oscillator that can drive food entrainment of circadian rhythms.
This paper is well worth a read. But if you want a quick overview, there is a nice radio interview about it here.
Basically, animal studies have shown numerous examples of circadian rhythm reset based on fasting and food reward. And even though there are no human studies on the phenomenon, I figured it was low-risk and that I had little to lose giving it a try.
This is the biohack.It is quite simple:
1. Do not eat anything for at least 12 hours, preferably 16 hours prior to the hour you want to be waking up. I wanted to wake up at 7am, so I ate nothing after 2pm. Drinking water is still necessary. And I would say weak tea with no sweeteners or milk or anything is fine too. Just don't drink anything with much in the way of calories OR taste reward.
2. However well you sleep that night, get up at your target time the next morning and immediately eat a large, highly calorific, delicious and rewarding breakfast. As in, go to town....Pig out....Treats unrestrained.... Personally, though I stuck with lipids as my primary choice of mega-calorific rewarding yum.
I ate a plate full of prawns cooked in coconut oil, buttery green vegetables, and sourdough buckwheat pancakes with clotted cream and fresh berries. I actually ate such a large amount of food that I didn't even feel the need for anything much for the rest of the day.
On the night of the pig-out day I got sleepy around 9pm, went to bed and slept through a full 9 hours for the first time in a week. It felt wonderful. Thereafter, I had no trouble sleeping at night and waking up in the morning.
My partner then arrived in London and tried the same thing. He got duck confit in his high reward/high calorie breaky....and slept like a baby every night thereafter. I tried it on myself again on returning to Australia. Bingo again, instant reset.
After years of battling to go to bed early and wake up in the morning, I am now finding that I have no problem whatsoever being an early riser and falling asleep as soon as get into bed at night. If I start to drift in my sleep pattern, I just go back to the fasting-reward tool for a night, and it slots right back into the rhythm that I want.
This is such a powerful and simple trick, I cannot believe more people do not know about it. Spread the word, and if you know someone struggling with sleep pattern regulation, make sure they know about it too.
2 things are crucial: Firstly, there must be a complete fast for 12-16 hours prior to the wake-up time, and secondly the breaking of the fast must be highly rewarding and calorific.
Kai-Florian Storch,and Charles J. Weitz (2009). ‘Daily rhythms of food-anticipatory behavioral activity do not require the known circadian clock’. PNAS vol. 106 no. 16: 6808–6813. doi: 10.1073/pnas.0902063106. This article has free open access and is linked here.
Ralph E. Mistlberger, Brianne A. Kent, Glenn J. Landry(2009). ‘Phenotyping Food Entrainment: Motion Sensors and Telemetry Are Equivalent’. Journal of Biological Rhythms Vol.24, No.1: 95-98. doi: 10.1177/0748730408329573.