Intermittent fasting can seem confusing to newcomers, but don’t overcomplicate it. In fact, you’re already doing it. Intermittent fasting just means periodic episodes of not eating followed by episodes of eating. For most, this fasting period occurs while we sleep, ending in breakfast where we “break the fast”. As far as dietary interventions go, most intermittent fasting (IF) protocols involve flipping those windows - increasing the time of the fast and decreasing the feeding window. Fasting periods range from 16 hours to a day and a half - and anything you can dream up in between.
Fasting and Sleep
Intermittent fasting can seem confusing to newcomers, but don’t overcomplicate it. In fact, you’re already doing it. Intermittent fasting just means periodic episodes of not eating followed by episodes of eating. For most, this fasting period occurs while we sleep, ending in breakfast where we “break the fast”. As far as dietary interventions go, most intermittent fasting (IF) protocols involve flipping those windows - increasing the time of the fast and decreasing the feeding window. Fasting periods range from 16 hours to a day and a half - and anything you can dream up in between.
Intermittent Fasting and Sleep
Science has shown that IF extends periods of insulin sensitivity stemmed by fasting periods. By depleting glycogen overnight (and extending it in to a daytime fast), your sensitivity to insulin spikes. When you do actually eat, you’ve got a much better chance of utilizing food as energy or storing it back as glycogen. You stop the feeding window before overwhelming the system, and the process starts all over again.
Intermittent fasting is sort of like cleaning up the clutter in your life and packing it in to a little box. In theory, improved function of everything else will follow, including sleep. IF has been shown to promote fat loss, improve mental clarity, and increase daytime energy.
As eating too much late at night can disrupt sleep, intermittent fasting often controls those complaints. And some studies suggest changing the eating window can actually change your sleep physiology.
Benefits
Varying your eating window can initially disturb sleep. It’s like adjusting to a new time zone. Your body will reject it as it fumbles around confused, trying to adapt to a new schedule. That’s because you’ve got a circadian rhythm running in your organs as well as your brain.
Circadian Rhythm Regulation
The circadian clock integrates with digestive and hormonal pathways. Research has shown varying feeding and fasting times can enhance the circadian regulators. The most common form of intermittent fasting, 16 hours of fasting followed by 8 hours of feeding, tends to shift the feeding window towards the night. Therefore, the “rest and recovery” section of our metabolism is condensed towards preparation for sleep.
Improved Sleep Quality
Not only could intermittent fasting help regulate your internal clock, it can also calm your restless nights. As part of a scientific study, participants downloaded a smartphone app to track their feeding window and sleep quality. When they asked participants to shorten their eating window from 15 hours to 11 hours within the day, the results were impressive. People reported much better sleep and more energy during the day.
Higher Melatonin Levels
A large portion of fasting studies on sleep are conducted during Ramadan. During this Muslim religious month of fasting, each day involves a fast from dawn until sunset. Research concluded that during Ramadan, blood melatonin levels were low at night. However, that’s after a significant period of fasting. Logic would follow that by shifting the fast to the morning and eating period toward the eve, melatonin levels will mimic that change.
To highlight this theory, another study of six healthy males were subjected to two straight days of fasting. Initially, they showed decreased melatonin levels. However, when some of these guys were given small, regular doses of glucose, melatonin levels returned to normal. This suggests that glucose levels are strongly connected to melatonin levels. By raising insulin sensitivity, the uptake of glucose increases, promoting higher melatonin levels and better sleep.
Drawbacks
For all of the benefits of intermittent fasting, there are a few drawbacks. After all, it’s not for everyone. Certain lifestyles, religions, or health conditions prevent intermittent fasting from being a viable option. Even if you don’t fall in this category, there are still some downsides to intermittent fasting.
Going to Bed Hungry
It can be incredibly difficult to fall asleep if you’re stomach is rumbling. If your feeding window hovers earlier in the day, leaving you hungry at bedtime, you might not be able to fall asleep. Consider easing in to an earlier eating window, or try eating your largest meal at the end.
Waking Up Hungry
On the other side, you might wake up starving and want to raid your fridge. A long fasting period can be an adjustment, and being annoyingly hungry at the start is normal. Drinking lots of water, coffee, or a BCAA supplement in the morning won’t technically break your fast, and these tricks can help you adjust.
Reduced REM Sleep
Unfortunately, a few studies have discovered REM sleep reduction during fasting. Four studies looking at Ramadan fasting showed decreased hours in REM sleep. They originally thought it might result from other lifestyle factors during the religious period. However, when a group of researchers controlled for this, they got the same results. Fortunately, they were able to return to baseline after fasting period were over.
Remember, though, that Ramadan involves diurnal fasting fasting - fasting during the entire day and eating at night (when one would normally sleep). There’s not much evidence involving other types of intermittent fasting and REM sleep, so it’s tough to say if it would produce the same result.
Conclusion
There’s lots of research on how intermittent fasting can improve inflammation, hypertension, and other negative health markers. For some, it can help regulate their circadian rhythms to get on a normal sleep schedule. If your eating window is later at night, you might find it easier to fall asleep with intermittent fasting.
But the big takeaway from all of this? You won’t know until you’ve tried it. For some people, intermittent fasting is a non-starter. For others, it may just be the key that unlocks a tranquil night and a productive day.
Intermittent Fasting and Sleep
Science has shown that IF extends periods of insulin sensitivity stemmed by fasting periods. By depleting glycogen overnight (and extending it in to a daytime fast), your sensitivity to insulin spikes. When you do actually eat, you’ve got a much better chance of utilizing food as energy or storing it back as glycogen. You stop the feeding window before overwhelming the system, and the process starts all over again.
Intermittent fasting is sort of like cleaning up the clutter in your life and packing it in to a little box. In theory, improved function of everything else will follow, including sleep. IF has been shown to promote fat loss, improve mental clarity, and increase daytime energy.
As eating too much late at night can disrupt sleep, intermittent fasting often controls those complaints. And some studies suggest changing the eating window can actually change your sleep physiology.
Benefits
Varying your eating window can initially disturb sleep. It’s like adjusting to a new time zone. Your body will reject it as it fumbles around confused, trying to adapt to a new schedule. That’s because you’ve got a circadian rhythm running in your organs as well as your brain.
Circadian Rhythm Regulation
The circadian clock integrates with digestive and hormonal pathways. Research has shown varying feeding and fasting times can enhance the circadian regulators. The most common form of intermittent fasting, 16 hours of fasting followed by 8 hours of feeding, tends to shift the feeding window towards the night. Therefore, the “rest and recovery” section of our metabolism is condensed towards preparation for sleep.
Improved Sleep Quality
Not only could intermittent fasting help regulate your internal clock, it can also calm your restless nights. As part of a scientific study, participants downloaded a smartphone app to track their feeding window and sleep quality. When they asked participants to shorten their eating window from 15 hours to 11 hours within the day, the results were impressive. People reported much better sleep and more energy during the day.
Higher Melatonin Levels
A large portion of fasting studies on sleep are conducted during Ramadan. During this Muslim religious month of fasting, each day involves a fast from dawn until sunset. Research concluded that during Ramadan, blood melatonin levels were low at night. However, that’s after a significant period of fasting. Logic would follow that by shifting the fast to the morning and eating period toward the eve, melatonin levels will mimic that change.
To highlight this theory, another study of six healthy males were subjected to two straight days of fasting. Initially, they showed decreased melatonin levels. However, when some of these guys were given small, regular doses of glucose, melatonin levels returned to normal. This suggests that glucose levels are strongly connected to melatonin levels. By raising insulin sensitivity, the uptake of glucose increases, promoting higher melatonin levels and better sleep.
Drawbacks
For all of the benefits of intermittent fasting, there are a few drawbacks. After all, it’s not for everyone. Certain lifestyles, religions, or health conditions prevent intermittent fasting from being a viable option. Even if you don’t fall in this category, there are still some downsides to intermittent fasting.
Rest
The bottom line is - nothing is as restorative as a consistent night’s sleep. Getting the rest both your body and mind need, however, often proves trickier than we would like. More and more of us experience sleepless nights and fatigue during the day, and modern society could be to blame.
Going to Bed Hungry
It can be incredibly difficult to fall asleep if you’re stomach is rumbling. If your feeding window hovers earlier in the day, leaving you hungry at bedtime, you might not be able to fall asleep. Consider easing in to an earlier eating window, or try eating your largest meal at the end.
Waking Up Hungry
On the other side, you might wake up starving and want to raid your fridge. A long fasting period can be an adjustment, and being annoyingly hungry at the start is normal. Drinking lots of water, coffee, or a BCAA supplement in the morning won’t technically break your fast, and these tricks can help you adjust.
Reduced REM Sleep
Unfortunately, a few studies have discovered REM sleep reduction during fasting. Four studies looking at Ramadan fasting showed decreased hours in REM sleep. They originally thought it might result from other lifestyle factors during the religious period. However, when a group of researchers controlled for this, they got the same results. Fortunately, they were able to return to baseline after fasting period were over.
Remember, though, that Ramadan involves diurnal fasting fasting - fasting during the entire day and eating at night (when one would normally sleep). There’s not much evidence involving other types of intermittent fasting and REM sleep, so it’s tough to say if it would produce the same result.
Conclusion
There’s lots of research on how intermittent fasting can improve inflammation, hypertension, and other negative health markers. For some, it can help regulate their circadian rhythms to get on a normal sleep schedule. If your eating window is later at night, you might find it easier to fall asleep with intermittent fasting.
But the big takeaway from all of this? You won’t know until you’ve tried it. For some people, intermittent fasting is a non-starter. For others, it may just be the key that unlocks a tranquil night and a productive day.
