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 two years.

Intermittent fasting and sleep have the power to transform your mind and health. Given my engineering background, I am continually running experiments to optimize my sleep and intermittent fasting plan. 

In this article, I’ll share my intermittent fasting before and after story as well as my experience intermittent fasting while focusing on sleep quality in parallel. 

intermittent fasting and sleep ryan and alex duo life clock timer

intermittent fasting and sleep

As we tell all of our clients if you’re focusing on a diet to lose weight, but ignoring sleep, you’re wasting your time.

The same goes for an intermittent fasting diet. Fortunately, sleep does count as fasting, and it’s the secret weapon to being successful.

Let me start by sharing my intermittent fasting sleep story. After that, we’ll dive into topics on fasting and sleep, including some of the sleep problems that intermittent fasters experience.

For example, we’ll cover questions about trouble sleeping or difficulty falling asleep, how to sleep when you’re hungry (hint- you shouldn’t), and what to do when you can’t sleep while intermittent fasting.

We have been researching and self-experimenting with fasting since 2018. For additional well-researched content backed by personal experience, check out the articles on our fasting page.

Intermittent Fasting Before and After


For four years, I slept only 6-hours a night. My typical day was waking up at 5 AM for a workout, eat my first meal at 6 AM, and my last meal at 11 PM before bed, consuming a total of three meals and two snacks during 18 waking hours.

On weekends or while traveling, if I missed a meal in that 18-hour eating window, I was not a happy camper. My self-control over my hunger was weak.

When a hunger pang struck, it was like a switch flipped. One word: HANGER!!

I needed to eat immediately and would go for the fastest meal or snack (rarely the healthiest). Although I was health-conscious, these incidents made my diet more volatile.

In addition to experiencing frequent hanger, I also suffered from extreme drowsiness, most commonly after meals.

The eating schedule I have described here is the opposite of a daily intermittent fasting plan.


In March 2018, I quit my job as an engineer to travel with my wife, Alex, and grow this website. This decision was a timely lifestyle change since I had sleep-deprived myself for over three years.

I was one of the many people who, due to sleep debt and workload, had to figure out how to recover from job burnout in my late 20s.

To say I was motivated to recover from burnout is an understatement. When I learned that at age 28 I had the testosterone levels of a 70-year-old man, I knew significant life changes needed to be made.

It was extremely eye-opening, and I was humbled by the importance of sleep for optimal health.

Needless to say, when I quit my job, quality sleep was my highest priority. And guess what… 4 years later I have increased my testosterone levels three-fold, naturally. Now my testosterone is that of a 17-year-old.

Fortunately, increasing my sleep hours made the transition to intermittent fasting much easier, because sleep does count as fasting.

Now, nearly two years later, I sleep 8-9 high-quality hours per night. When I wake up around 8 AM, I work out, read, and eat breakfast at 11 AM.

I consistently eat two to three large meals a day. I am rarely hungry in the morning or at night while following a 16-hour fast, or the 16/8 plan. I finish my 8-hour eating window after dinner at 7 PM.

I started gradually, eating for 10 hours and fasting for 14 hours. It wasn’t easy at first (more on that later). However, my goal to get more sleep almost accidentally aligned me with a 16/8 intermittent fasting plan.

Ironically, this 16 8 window was the exact opposite of what it was the year before. So, what were the benefits of intermittent fasting and focusing on quality sleep? I am glad you asked.

Intermittent Fasting and Sleep Benefits

In retrospect, my health and well-being improved tenfold.

I maintain a healthy weight and never have fatigue during the day or after a meal. My hanger is no longer an issue, and I have full control of my hunger.

When I wake up in the morning, I feel focused and ready to hammer out my day’s to-do list. Now, I drink my coffee because I enjoy the ritual, not because I need it to function in society.

I can’t say what percentage of these improvements are due to overcoming sleep deprivation or becoming an intermittent faster.

However, I can proclaim that both are closely related and have been paramount to my new-found physical energy and mental vitality. Both intermittent fasting and sleep have a similar cleansing effect on our brain and body.

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, brainpower is processing the stress of the day. 

In short, the benefit of quality sleep and intermittent fasting is a higher functioning mind and body. For a deeper dive into the scientifically proven health benefits of intermittent fasting, open the below article in a new tab.

My Takeaways on Intermittent Fasting and Sleep

By focusing on intermittent fasting and sleep at the same time, the diet has seamlessly worked itself into my lifestyle. I would not recommend IF to anyone who is not committed to sleeping 7-9 hours a night.

Intermittent fasting is challenging at first. However, if you transition gradually and eat right, intermittent fasting should not impact your sleep. Instead of making you sleep less, it should help you sleep more. 

While gaining muscle and losing weight is a possibility when you follow intermittent fasting, that shouldn’t be the focus of your new diet. Instead, focus on the opportunity to improve mental clarity and energy levels.

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

In the next section, we’ll attempt to troubleshoot sleep challenges that go along with intermittent fasting and learn about what to expect if you’re new to intermittent fasting. 

Intermittent and extended fasting bundle - printable pdf guide

The Proven Fasting Bundle (Printable PDF Guide)

Read by 143,364 fasters in 2022 alone, the Fasting Bundle is the structure and tools you need to succeed.

  • Intermittent and alternate-day fasting meal plans
  • Checklist for before, during, and after a prolonged fast
  • Benefits, challenges, and a beginners how-to guide

Plus, we're just an email away for support.

questions about sleep and intermittent fasting

Answers to the following questions are based on my personal experience, the experience of clients, and scientific studies.

Additionally, the content was reviewed by multiple doctor and nutritionist friends in our network. Still, if you’re having trouble sleeping or are not sure if intermittent fasting is right for you, please speak with your doctor.

Does sleep count as fasting?

Yes, your intermittent fasting window includes sleep.

Sleep is considered fasting. Therefore, the more you sleep, the less you have to be awake in a fasted state. That makes it easier because you’re unconscious while your stomach is growling.

How does IF directly improve your sleep quality?

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.

Some people report not sleeping well while intermittent fasting. We’ll cover some common causes. Intermittent fasting should not cause sleep problems.

However, if two months of implementing and experimenting with what you learn in this article and our step-by-step how-to guide proves unhelpful, it might not be the best eating plan for you.

I personally have never had recurring sleep struggles while intermittent fasting, however, I had major difficulty sleeping during an extended 3-day fast.

Our 3-day fast results and what we experienced were incredibly eye-opening.

We lost a combined 16 pounds and both experienced a metabolic switch around 55 hours. When done properly, extended fasting is a safe and effective way to reset your hormones and kick your body back into a fat-burning state.

We write all about our experience (sleep study included) and how to prepare for, execute, and break a 3-day water fast. Open the below article in a new tab to hear our before, during, and after story, results, and plan that you can replicate.

How does fasting improve your health?

Most importantly, while fasting, your body secretes less insulin and more human growth hormone. 

These hormonal changes are one of many evidence-based benefits of intermittent fasting. More HGH means your brain and organ tissues are better maintained and strengthened.

Intermittent Fasting Tips for Beginners

Any change in routine comes with challenges. If you follow these tips, it should be easy. If you don’t, not only are you making it harder on yourself, but you could also be jeopardizing your results.

Not only with these simple and effective reminders help you see better results, but they’ll also help you increase your sleep quality. 

1. Don’t be too strict

The most important thing for beginners is to listen to your body and adjust accordingly. For example, if a 16/8 plan is too extreme, begin with a 12/12.

Or, if you’re consistently going to bed hungry while intermittent fasting, the short-term solution is a bedtime snack, while the long-term goal is to eat more food.

1. Sleep more

By now, hopefully, I have you sold on this tip. The longer sleep window makes transitioning to a shorter eating window more easily. You’re asleep while your stomach is growling.

Simple. Sleep for 7-9 hours.

 2. Eating enough food

More Food? Yes, and this is really important. I believe calorie (nutrient) deprivation hugely impacts your sleep quality.

When I started IF, I constantly double-checked my calories. I made sure I was eating the correct amount of calories in my shorter eating window.

This is hard at first because you might have to eat when your body isn’t screaming at you, “I’m hungry!”

If you don’t know how to calculate your calories, look at the instructions for our 30-Day Weight Loss Challenge. People who start intermittent fasting have a tendency to eat too few calories.

At first, I had to schedule my meals because I wouldn’t be hungry yet. Try setting an alarm on your phone to remind you when to eat.

People don’t lose weight intermittent fasting because they are eating less food. Correction: they don’t lose weight and keep it off if they are calorie deprived. The IF rules say that you eat the same amount of calories, just in a shorter time.

Restricting calories will cause a weight loss plateau, or, even worse, make you gain weight.

3. Do morning workouts

I was apprehensive about working out on an empty stomach. Fortunately, it was not a problem at all after a short time. I even noticed my workout performance increase.

There were a couple of instances when I became 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. As always, listen to your body and avoid deprivation.

This is so important and effective, we wrote an entire article (with workout suggestions) on how to do intermittent fasting and morning workouts

4. Experiment with hunger control

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.

During this time, it’s essential to adjust gradually. That’s why I started by eating for 10 hours and fasting for 14. Drinking water or coffee in the morning helped too.

Also, fight through hunger by being mindful. Focus on the positive side of hunger, which is that you’re allowing your body time to process toxins and optimize mental and physical performance.

Additionally, focus on increasing your self-control. By fighting through hunger, you are calling the shots, not your grumbling stomach.

Battling hunger is especially hard if you are trying intermittent fasting and waking up early, like at 4 AM. People always ask me how to do intermittent fasting when you wake up early.

If this is you, I recommend waiting to eat your first meal for 5-6 hours and eating your last meal 3-4 hours before bed. To make intermittent fasting work with an early start, you must go to bed early. That could mean that you’re having dinner at 4 PM.

5. Create a new Schedule

Starting intermittent fasting requires a schedule change. For most, that means a new morning ritual. Adjust your wake-up, workout, and breakfast time, and know that you might not nail it on the first try.

I recommend working out first thing, drinking a lot of water, and having an intermittent fasting distraction drink while you complete your most daunting to-do list tasks. Most intermittent fasters report extremely high focus and productivity in the morning.

A distraction drink is something to fend off your hunger and wake up your digestive system. As long as your drink is less than 50 calories, that’s not breaking your fast, according to intermittent fasting rules. We prefer to drink black coffee or the below digestive drink.

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).

Eventually, you’ll have to break your fast with breakfast. Again, this is extremely critical and there are certain foods your should and should not eat. We wrote a separate article on how to break a fast the right way

6. Eat healthy

The transition to a shorter eating window is easier for individuals who eat a healthy diet and stay hydrated. If you’re lacking nutrients and calories, your transition is going to be much harder.

Additionally, the road to quality sleep while intermittent fasting is going to be a bumpy one. 

Use your new IF plan to further motivate you to eat healthier. A healthy diet consists of fiber-filled carbs, healthy fats like nuts and avocados, high-quality animal products, and as many vegetables as possible.

How To Improve Sleep While Intermittent Fasting

We all know how hard it can be to fall asleep when you’re hungry.

If you’re new to intermittent fasting and having difficulty sleeping or waking up at night, the following advice will help. If you need more help, feel free to ask in the comments section.

The goal with intermittent fasting, as it was for me, should be to get more and better quality sleep.

1. Find what works for you

We’re all unique individuals. Therefore, our body’s 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 10 or 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. Then, over time, you can determine how the foods you eat are 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.

Sleep is complex. If you’re intermittent fasting and can’t sleep, there are likely many factors, not just your new eating schedule.

Could it be possible that you are spending too much time looking at a screen? Or are you drinking too much alcohol?

2. 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 drinking a gallon of water a day experiment we conducted.

Elevation exponentially worsens the effects of dehydration on sleep, so it was a perfect environment for this study. The conclusion: dehydration yields a more restless night’s sleep followed by drowsy mornings.

Yes, you can drink water while intermittent fasting. And, you should. Lots of it!

You can also drink coffee during your fasting window, but that doesn’t mean you should overconsume. If you need help cutting back on caffeine, you will find our experiment (documented hour by hour) on caffeine withdrawal helpful.

3. Monitor your meals

Intermittent fasting and sleeping will both deliver optimal results when paired with healthy food.

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.

Studies have also shown that this is beneficial for weight loss. 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, nobody knows what is best. This is why self-experimentation and collecting data are crucial. We recently discovered the Lumen metabolism tracker and it recommends what to eat based on real time metabolism measurements. 

For years, the only way to get metabolic data was in a lab. This was far too expensive and inconvenient for anyone who wasn’t a professional athlete.

But now, you can get this information immediately and at home with a little device called Lumen.

It works like a breathalyzer and measures the carbon dioxide in your breath. Not only will it tell you that you’re burning 25% fat and 75% carbs at that exact moment, it will make recommendations on what to eat today to optimize your metabolic flexibility.

Our results and experience, which we share in our full Lumen Review, have been game-changing.

4. Take a holistic approach

Sleep science has 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 or stretch with some couples yoga poses.

It’s unlikely that intermittent fasting causes insomnia. Alternatively, screen time is a significant contributor to the rapidly increasing cases of insomnia. 

Second, make your bedroom a sleep sanctuary. Invest in a sound machine and a sleep mask.

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.

We also highly, HIGHLY recommend you read the book Why We Sleep.


Intermittent Fasting Sleep FAQs

What are good intermittent fasting hours?

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. As a beginner, especially for females, this is an excellent starting point. If you continue to struggle with sleep, stick to a 12-hour window or give up IF altogether.

What are the benefits of IF? How does it improve sleep?

There are many scientifically proven health benefits that intermittent fasters 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’s sleep.

Is Intermittent Fasting or Sleep More Important?

Hands down, sleep.

Sleep is critical for every function of our mind and body. Again, 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 can live before I’m dead.”

It’s true. I used to feel guilty about sleeping since it took time away from my side hustle. 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, science shows that with intermittent fasting you can lose weight and gain muscle.

In addition to higher production of human growth hormone (HGH) and increased metabolism, 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 body’s ability to metabolize body fat. Therefore, 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.

These factors are also contributing to why you can’t sleep while intermittent fasting.

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.

Closing Thoughts on Intermittent FastinG and Sleep

We hope this article has helped you understand the importance of sleep and how intermittent fasting can be beneficial.

Feel free to download our Proven Fasting Bundle to help you reach your goals and leave any specific questions about fasting and sleep in the comments below. We prefer that to email because the discussion helps all future readers. Thanks!

For general questions about fasting, such as why you’re not losing weight on intermittent fasting, head over to our Fasting Page.

Intermittent and extended fasting bundle - printable pdf guide

The Proven Fasting Bundle (Printable PDF Guide)

Read by 143,364 fasters in 2022 alone, the Fasting Bundle is the structure and tools you need to succeed.

  • Intermittent and alternate-day fasting meal plans
  • Checklist for before, during, and after a prolonged fast
  • Benefits, challenges, and a beginners how-to guide

Plus, we're just an email away for support.

30-Day Weight Loss Challenge Tracker Form V2 Ryan and Alex Duo Life

30-Day Weight Loss Challenge

As engineers with a combined twelve years of health coaching experience, we needed to create a data-driven way for our clients to sustain weight loss.

Too many weight loss challenges involve a long list of what you can, cannot, and need to do every day. We’ve reduced the overwhelm and only require you to track five numbers a day — calories, steps, fiber, sleep, and waistline.

You’ll track five numbers daily to give you the highest return for sustainable weight loss. As a bonus, we’ll share our Weight Loss Bundle, which includes strategies, progress tracking tools, and additional weight loss plans.

Learn more about the program.

As Seen In Feature Bar Ryan and Alex Duo Life

Hey we're Ryan and Alex

The creators of Ryan and Alex Duo Life. We are a husband-wife duo and “lifestyle engineers.”

After eight years working in the corporate world as engineers, we left our high-powered jobs to tackle our true passion — helping couples 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.

Duo Life Newsletter Signup Example Image

Optimize Your Life, One Friday at a Time

Enter your name and email address to sign up for our free newsletter, the Duo Life Letter. Each Friday receive evidence-based tips to elevate your health and relationship.

Pin It on Pinterest