Intermittent Fasting and Sleep

Intermittent Fasting (IF) is a hugely popular dieting method. After polling our Instagram follower’s nutrition questions, 70% of them were IF related. Coincidentally, I have been an accidental intermittent faster for one year.

It happened because I was focusing on sleep. Intermittent fasting and sleep have the power to transform your mind and health. Here are my intermittent fasting story and recommendations to help you get started while mastering quality sleep at the same time. 

my intermittent fasting and sleep story

Eating Before I Focused On Sleep.

For many years, I slept only 6-hours a night. If I woke up at 5 AM, I would work out and eat breakfast by 6 AM. During the day, I had three big meals and two snacks. I went to bed at 11 PM, which meant I had been awake 18-hours.

On weekends or while traveling, if one of the meals in that 18-hour eating window was interrupted, let’s say I was not a happy camper. My self-control over my hunger was weak.

Although I was eating healthy foods when a hunger pang struck, it was like a switch flipped. One word: hanger. I felt like I needed to eat immediately and would grab the fastest thing — which usually wasn’t the healthiest.

Is this familiar?

Eating After I Focused On Sleep.

One year ago, in March 2018, I quit my job as an engineer to travel as a digital nomad. This decision was a timely lifestyle change since I had sleep deprived myself for many years. I got caught up in climbing the corporate ladder.

Anyway, years of sleep deprivation caught up to me and experiencing burnout and low testosterone in my 20s was eye-opening. So, when I quit my job, my new priority was sleep.

Since then, I have slept 8-9 high-quality hours per night. When I wake up at 8 AM, I work out, read, and eat breakfast between 10 and 11 AM. I consistently eat three large meals a day, with dinner being at least 3-hours before bedtime. Therefore, I have dinner at 6 PM, finishing my 8-hour eating window.

In the last year, my goal to get more sleep almost accidentally aligned me with a 16:8 (16-hours of fasting with 8-hours of eating) intermittent fasting plan. Ironically, this 16:8 window was the exact opposite of what it was the year prior!

Benefits Of Focusing On Intermittent Fasting and Sleep

In retrospect, my health and well-being improved threefold. I maintain a healthy weight, fatigue during the day is a rare occurrence, and the quality of my sleep is incredible. No more tired mornings. Also, I drink coffee because I enjoy it, not because I need it to function in society.

It’s hard to say if these improvements are due to overcoming sleep deprivation or becoming an intermittent faster, but the two are closely related. Both intermittent fasting and sleep have a similar cleansing effect on our brains.

When you aren’t fasting, your body and brain have to process what you’re ingesting. While fasting, your body and brain can focus on detoxing and distributing nutrients properly to optimize your physical and mental performance.

Similarly, this process also happens while you’re sleeping. When you don’t sleep enough, your brain doesn’t have adequate time to store and process memories, for example. Instead, it’s consumed with processing the stress of the day. 

My Conclusions

By focusing on intermittent fasting and sleep at the same time, the diet has seamlessly worked itself into my lifestyle. The most noticeable result of IF is that I don’t have hanger anymore. I have full control over my hunger. Unconsciously opening the fridge before bedtime is no longer a regular occurrence.

Also, intermittent fasting makes me feel highly focused throughout the day, and my energy levels are more balanced. Since, I avoid the cycle of feeling starved, overeating, and then crashing.

intermittent fasting and sleep recommendations

Hopefully, you are in a fasting state while you’re sleeping. Then, with intermittent fasting, you’ll be extending this fasting period. While fasting, your body is secreting less insulin and more human growth hormone. 

These hormonal changes are one of many evidence-based benefits of intermittent fasting. Regarding sleep, studies suggest that intermittent fasting positively influences your circadian rhythm and your body’s ability to manage REM sleep. Both of which are critical to falling asleep, getting quality sleep, and waking up well-rested and ready for the day ahead.

The following recommendations are backed up by my personal experience, the experience of our clients, and scientific studies.

What To Expect When You Start IF

What might be easy?

For myself, and clients that we’ve worked with, many aspects of the IF diet came naturally. Firstly, the longer sleep window makes transitioning to a shorter eating window more natural. You’re asleep while your stomach is growling. 

Secondly, the transition to a shorter eating window is easier for individuals eating a healthy diet and staying hydrated. For myself, a healthy diet consists of fiber-filled carbs, as many vegetables as possible, and healthy fats like nuts and avocados.

Thirdly, I was apprehensive about working out on an empty stomach. I thought it was easy, and I even thought my workout performance increased. There were a couple of times early on when I got dizzy while working out in a fasted state. I stopped, drank water, and ate a banana. After a few minutes, I was ready to go again. 

What might be hard?

The hardest part for most is the hunger in the morning and before bed. During the first two months of IF, I woke up feeling starved. Drinking water helped, but it wasn’t enough.

First, I fought through by being mindful. I would focus on the positive side of my hunger, which was that I was allowing body was processing toxins out and optimize my mental and physical performance.

I also focused on increasing my self-control. By fighting through hunger that meant I was calling the shots, not my grumbling stomach. This attitude of self-control spills into all areas of your life. For example, eating frogs on your goal-oriented to-do list.

If you have to get up early, like 5 AM early, wait to eat your first meal for 5-6 hours. 

Secondly, I double-checked my calories. I made sure I was eating the same amount of calories in my new 8-hour eating window compared to the old 18-hour window. This requires an adjustment period. But, the process is far more difficult if you’re not eating enough.

At first, I had to schedule my meals because I wouldn’t be hungry yet. Set an alarm on your phone reminding you when to eat. Also, use the app MyFitnessPal to make sure you are eating the right amount of calories. Regarding weight gain, not eating enough is just as bad as overeating.

Read more: How to prevent the weight loss plateau.

Thirdly, a morning ritual helps many. We recommend this morning digestive drink to distract you from your hunger and wake up your digestive system. As long as your ritual is less than 50 calories, that’s not considered breaking your fast. So, black coffee works well too. 

Morning digestive drink:

  • One cup of hot water
  • One half a lemon squeezed (excites digestive enzymes)
  • Two caps full of apple cider vinegar (balances pH levels in the gut for healthy bacteria growth)
  • A pinch of cinnamon (to stabilize blood sugar levels).

Read more: How to improve poop health 101.

How To Improve Sleep While Intermittent Fasting

Trust me. I know how hard it can be to fall asleep when you’re too hungry. If you’re new to intermittent fasting and having difficulty sleeping, the following will help you if you can’t sleep, or if you are waking up at night. The goal with intermittent fasting, as it was for me, should be to sleep more and better quality.

You do you.

We’re all unique individuals. Therefore, our bodies response to IF can vary. Instead of getting caught up in studies, facts, or what worked for your friend, engage in self-experimentation. 

Try various eating windows. If you’re eating in a 6-hour window and not sleeping well, scale back to a 12-hour window. Your cortisol levels may become too high with such a long fast. Excess cortisol makes it hard to fall asleep and sleep soundly.

Also, keep a journal of what you’re eating, when, and how you sleep. Now, over time, you can determine how your diet and intermittent fasting is affecting your sleep.

Lastly, try adjusting your bedtime. Listen to your body, and when your circadian rhythm nudges you to go to sleep, do it. If you’re too hungry to sleep, maybe you’re staying up too late. 

Drink more water.

Keeping hydrated will help you avoid hunger pangs while improving your mood and energy level. Dehydration negatively affects sleep. I know this first-hand from a hydration and sleep experiment I conducted while living at high elevation.

Elevation exponentially worsens the effects of dehydration on sleep. The conclusion: dehydration yields a more restless night sleep followed by drowsy mornings. 

Read more: The importance of drinking enough water.

Monitor your meals.

Intermittent fasting and sleeping well both deliver optimal results when eating healthy. Again, keep a journal of what you’re eating and how it makes you feel. Some people find that dairy products make them sleep less soundly, especially when consumed at night. As you journal, look for patterns like that. 

You need to run your own tests, but a lot of people sleep better when they have a big breakfast and a smaller dinner. It’s essential to make sure you’re not still digesting when it’s time for bed. Eat dinner 3-4 hours before bed. 

And what about carbs? In the same day, I listened to a podcast by a nutrition expert who said, “Carbs are energy, and you don’t need energy before bed,” and read an article from a reputable source that said, “Carbs will increase your serotonin production and therefore help you sleep.”

The point is, who knows what is best? Only you do. And you only know through implementation followed by trial and error. I am vegetarian, and the healthy, fiber-filled carbs I eat for dinner do not cause difficulties sleeping.

Use common sense.

Sleep Science had become much more conclusive in the last 20-30 years as MRI scanning technology becomes more advanced. Scientists can run tests and then collect data on how the human brain responds. There are certain things we now know conclusively.

First, don’t work on your laptop or use any screen (TV included) before bed. Your brain needs time to wind down. Instead of scrolling social media on your phone, read a book. It’s unlikely that intermittent fasting causes insomnia. Alternatively, screen time is a significant contributor to the rapidly increasing cases of insomnia. 

Second, invest in a sound machine and a sleep mask (this is the most comfortable and blackout mask we have found). We use blackout curtains at home, but when you travel a lot, a sleep mask ensures that it’s pitch black in every room you sleep.

Third, if you’re  inclined to learn more about the processes and the products that we have used to optimize our sleep, check out our article on the importance of sleeping well.

Is IF Beneficial?

Intermittent fasting is beneficial. Not to mention, it can be an enjoyable process when you combine intermittent fasting and a good night of sleep. It feels good to have control over food, rather than the other way around.

A lot of experts on the relatively new topic say that a 14-hour fast (10-hour eating window) is the minimum for IF to work. In my opinion, anything beyond an 18-hour fast (6-hour eating window) is too extreme and too hard to sustain.

But, you can still reap the benefits of intermittent fasting by restricting yourself to a 12-hour eating window. There are many scientifically proven health benefits that intermittent fasters can enjoy, such as maintaining healthy body weight, balancing blood sugar levels, providing insulin resistance, and reducing the risk of diabetes, one study shows.

There are also scientifically proven sleep benefits. In one pilot study, results showed that short-term fasting reduces the frequency of awakening and disruptive body movements, yielding a more sound night sleep. 

Is Intermittent Fasting or Sleep More Important?

Hands down, sleep. Sleep is critical for every function of our mind and body. If you haven’t read the book Why We Sleep, by Matthew Walker, you should. It will change your mindset from “I’ll sleep when I am dead,” to “I’ll sleep 8-hours every night, so I don’t die young.”

It’s true. I used to feel guilty about sleeping since it took time away from my side business. Now I cherish it and know that prioritizing it is the smartest use of my time.

If you prioritize sleep, intermittent fasting is a natural progression. If you prioritize intermittent fasting and not sleep, you won’t get results.

That’s because adhering to your window, avoiding cheat foods, limiting alcohol, and having the energy to celebrate progress will become nearly impossible.

Can I Lose Weight or Gain Muscle with IF?

Yes, with intermittent fasting, your body and brain have more time to use the nutrients you ingest to optimize your health. Additionally, studies show that intermittent fasting improves our bodies ability to metabolize body fat. So, if you are eating well while intermittent fasting, you should see weight loss.

Conversely, if you are not eating healthy foods consistently or drinking too much alcohol, don’t expect to lose weight solely because you adjusted your eating window.

My goal with intermittent fasting was to gain some muscle mass. I needed to eat a lot of calories in a short time to achieve this goal. I have gained (and maintained) muscle mass by doing significantly less work.

Before I prioritized sleep and started intermittent fasting, I would weight lift 5-6 days per week for 45-minutes. Now I lift only 3-times per week (only with resistance bands) for 30-minutes and fill in the rest of the days with cardio and yoga.

Regarding exercise, I am getting more bang for my buck now that I am intermittent fasting. Having highly effective workout programs to follow helps too.

Read more: How to Manage Diets as a Couple


Other questions about my experience with intermittent fasting and sleep? Do you have an IF experience that can help us? Post in the comments below.

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Hey we're Ryan and Alex

The creators of Ryan and Alex Duo Life. We are a husband-wife duo and “happiness engineers.” After eight years working as corporates engineers internationally, we left our high-powered jobs to tackle our true passion — leading couples to engineer their best lives. The synergy of our engineering minds and ten years of health coaching experience produced Ryan and Alex Duo Life. Our mission is to help you transform your bodies, minds, and relationship, as a couple.

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