Can’t Sleep?

When I stumbled upon intermittent-fasting, I didn’t know that it could mess with my sleep…

Maybe it was my lack of research but all of the blog articles and Reddit posts I’d read were preaching the amazing benefits of fasting, I saw nothing about insomnia.

When I had trouble sleeping, I was unsure whether it was because of my fast or something else. So I did a bit of research and found that it is a normal side effect. It just would have been nice if someone had said “Pssst… You won’t get much sleep at the beginning.”, Just so I knew what to expect.

  • Fasting does cause sleep issues temporarily
  • Sleep issues are fairly mild/nothing to worry about

So if you are new to fasting, this post is for you. 

It’s Not as Bad as You Might Think

Thankfully, My quality of sleep did improve with time. The more I fasted the easier it became. It took three nights of being unable to sleep and wondering if “this fasting thing is for me” before my sleep returned to normal. On the fourth day I went into ketosis. This ended up in me getting the best night’s sleep of my life – Not joking.

  • Expect to be unable to sleep much at first
  • Sleep returns to normal once your body gets used to the fast

What I didn’t know was that your need to sleep decreases during a fast. I couldn’t sleep at night because I was full of energy. I was also full of energy during the daytime. I wouldn’t be sleepy during the day despite not getting a proper night’s sleep. In the night I felt tired but I just couldn’t sleep. I’d lay in bed for hours trying to fall asleep but I’d never drop off. A few nights passed and I noticed that I wasn’t actually tired. I just wanted to sleep because I thought I’d be worn out the next day otherwise. Every morning though, I had just as much energy (if not more) than I’d have from a good nights rest. I also got to enjoy getting more things done now that I didn’t have to spend time thinking about, preparing and eating food.

  • You are less tired while fasting
  • You’ll have extra energy during the day and night

If you’re reading this blog post because you’re just starting your fast and can’t get to sleep, I’d like to offer you this bit of advice: Unless you’ve got something really important to do tomorrow that you don’t think you’ll be able to power through without sleep, hang in there. Take comfort in knowing that it’ll get easier once your body adapts to your new eating pattern, I promise it’ll be worth it. Otherwise you could always postpone the fast until you have some downtime where you don’t have much to do the next day.

  • Arrange your fast so that you start when you don’t have anything important to do


When you fast, your body releases something called orexin. Orexin (also known as hypocretin) is a neurotransmitter that keeps us alert, makes us want to eat, increases body temperature and boosts metabolism. Low levels of orexin in mice has been linked to obesity even when they take in less calories than usual. If you have high levels of orexin, you wont need or be able to sleep. You will be full of energy and more alert. The only thing that will make you tired is lowering orexin (eating junk food).

Have you ever wondered why we get tired after eating a ton of processed food?. I remember eating a full tub of Ben and Jerry’s and instantly crashing out on the sofa for a few hours. Surely all that sugar should have given me more energy but instead it put me to sleep… This is because when glucose is released into the blood it suppresses the flow of orexin, This causes fatigue and makes us unmotivated to be active. 

  • High orexin = High energy, More Alert
  • Low orexin = Low energy, Fatigued

When you look at things from an evolutionary stand point, this starts to make sense. When we were feasting we needed to sleep for our bodies to digest the food we were eating, during a fast however we needed to be more alert and awake so we could find food to eat. 

  • Eating decreases orexin
  • Fasting increases orexin

The other hormone/neurotransmitter that gets released is adrenaline.

Adrenaline is known to cause weight loss by breaking down fat stores and burning them. Adrenaline is also known to decrease appetite. The downside to adrenaline of course is that it keeps you awake and that’s all fine and dandy in the middle of the day when you’re at work but when it’s 2am and you can’t sleep because your mind is racing… Not such a welcome side effect.

  • Fasting triggers fight or flight response which releases adrenaline in to your system

Why is adrenaline released and how long does it last?

When you start your fast your body switches from running on carbs (energy from food) to running on ketones (energy from fat). This is called becoming keto adapted. You will burn fat for energy when you are keto adapted instead of carbs. Switching in and out of ketosis is what causes adrenaline to be released. That’s why many people follow a keto diet (low carb/high fat) on feeding days so that they can remain in the keto adapted state and avoid sleep trouble.

  • Your body is not used to going without food, this triggers fight or flight response.
  • After a few days your body adapts and sleep resumes

The process of becoming keto adapted isn’t instant though. It’ll usually take  48 – 72 hours for your body to switch over. It is during this switch-over period that adrenaline is released. If you’ve spent your whole life relying on food for energy and then you suddenly stop eating, your fight or flight response will kick in so that you’re more alert and have the energy needed to get more food. That’s why you find yourself lying awake at night instead of dozing off. When you choose to push through this period until you’re in ketosis the adrenaline will subside and your sleep should return to normal. Your cravings/hunger will also decrease. I know when I’m in ketosis because I have no desire to eat whatsoever. The sight/smell of food has no control over me either, unlike it does during the switch-over period.

  • When we eat too much food we store it as fat
  • Ketosis is the process of using stored fat as energy


Actually, Yes.
You’re probably stressed right now because you can’t sleep. No sleep means you’ll be sluggish in the morning right? – Wrong. What I and many others have realized is that when you fast you need less sleep.

When I started fasting I thought If I didn’t get 8 hours of sleep per night I’d be exhausted the next day but most of the time it was completely the opposite, I had more energy than usual even though I only got five hours of sleep the night before. The high levels of adrenaline and orexin keep me alert and full of energy.

  • Energy from orexin and adrenaline eliminates fatigue during the day

I fast for greater physical and mental efficiency – Plato


Some people choose to fast to improve work performance. Silicon Valley CEO’s have started asking employee’s to optionally fast once a week because of it’s positive effects on the brain.

Fasting not only fills you with energy but makes you more productive. People notice a sense of mental clarity during a fast. The main reason for this is because it improves brain function by producing a protein called brain-derived neurotrophic factor (BDNF), Which makes your brain run more efficiently. High levels of BDNF is also known to lower Alzheimer’s risk and help with anxiety and depression.

Your body also needs less recovery time when you are in a fasted state, you have no food to digest so you expend less energy on digestion. This energy can be reallocated to other areas, such as productivity.

  • Increased BDNF results in mental clarity
  • Increased orexin and adrenaline results in better focus



1. Sleep Hypnosis

This is my favorite, It’s my go to whenever I can’t sleep. I fire up YouTube on my phone and look for the best sleep hypnosis video, I put my earphones in, Lay back and within 30 minutes I’m sleeping like a rock. If I’m honest I felt a bit silly when I first decided to try this but I was so sleep deprived, I would’ve tried anything. So I gave it go and I’m glad I did because it worked first time.

  • Sleep hypnosis is highly effective

After seeing how effective it was, I can now see that the joke was on me for laughing at it in the beginning. Please give it a go before dismissing it, you’ll thank yourself for it in the morning. 
Here is a video I like to use and it knocks me out without fail:

2. Binural Beats

This one is a little like the hypnosis method above. it works by playing two different tones in each ear (so you need stereo headphones for this to work), When the tones are played it increases delta brainwaves which are most commonly associated with deep sleep. A little off-topic but binural beats have many uses not just to sleep. I recently used this video to get rid of toothache and it seriously does work. I do find this just as effective as the hypnosis method and I use it when I don’t feel like listening to somebody talk.

Here is my favorite video:

3. Jump in the bath or shower

We all know that bathing or taking a shower is incredibly relaxing but did you know it could help you get a better nights sleep?

Studies show that when you leave a hot steamy shower or bath your temperature drops quickly, this induces a sleepy feeling because your heart rate decreases, which in turn makes your whole body slow down, The same way it does before entering a deep sleep.

4. Calm anxious thoughts

If you can’t get to sleep because your mind is racing with anxious thoughts, you can try replacing them with meaningless lists to calm your mind. The objective here is to completely take your mind off whatever is worrying you. You can do this by creating lists of anything you feel like in your head, I think of music whenever I do this. I organize around 10 songs in a list in my head. My favorite song to my least favorite, but you could do it with whatever you like, you could make a list of furniture for your imaginary dream home or just create a shopping list. Simple meaningless lists can take your mind off anxious thoughts and let you get the sleep you need.

5. Visualize physical action

Try to imagine yourself doing your workout routine or taking a walk somewhere familiar, think of it in as much detail as possible, from start to finish. this could be anything you like. For me personally I play pool and I imagine potting every ball one after the other but you could practice yoga, running, whatever you like. This visualization technique not only takes your mind off the fact that you can’t get any sleep but also tricks your brain into thinking you are dreaming so that you start to feel sleepy.

6. Open the windows

You need fresh air if you want a good night’s sleep, It’s important for achieving a deep sleep. A study done by Eindhoven University of Technology found that improving ventilation in your room by opening windows and doors increased the quality of sleep in the 17 participants. 

“Lower ventilation rates are likely to affect sleep quality negatively,” Dr. Asit Mishra


I used to be the worst for this. I’d close my door and window in my tiny bedroom to avoid any noise and then I’d wonder why I couldn’t get any sleep. After reading up on this, I now keep my door and window wide open. The flow of oxygen is far more important than silence when it comes to sleep quality. I no longer wake up every 45 minutes like I used to.

7.  Optimize your room

Your sleeping environment is a big factor in the quality of sleep you recieve. You should aim to create a welcoming bedroom that you enjoy spending time in. Keep your room tidy, A tidy room makes for a tidy mind. You can use a blackout blind to make your room completely dark.  Avoid technology in the bedroom. Technology is a real distraction and can lower your sleep quality (unless you are using it to listen to binural beats/sleep hypnosis audio). If you are using your phone for an alarm you should consider using an old school alarm so that you don’t check the notifications on your phone every half hour. The light that the screen on your phone gives off is actually stimulating to us. That’s why sleep experts recommend banning all technology from the bedroom.


While fasting does temporarily impair sleep quality, I wouldn’t let that put you off. I think the good effects outweigh the bad and being super-focused and full of energy during the day was worth losing a little sleep over. The reason most people want good sleep is so that they aren’t sluggish the following day. When you are fasting, no matter your sleep quality, you won’t get fatigued. Between the orexin and adrenaline keeping you alert and the ketones providing you with a constant, steady flow of energy, You’ll find it hard to feel fatigued.

  • If you are struggling with hunger during a fast click here 

I hope you choose to stick with it and wish you the best of luck in all your fasting endeavors. Let me know your thoughts by commenting below.


  1. Thank you so much for putting this so clear. This is why I prolongue. Now I understand. Have the oura ring and wanted to track better sleep like my carnivore peer but nothing to track. No sleep 😀

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