In this article, we are going to share our experience and the research to teach you how to do a 3-day fast successfully.

We cover how to prepare for a fast, highlight the 3-day fast benefits, share our 3-day water fast before and after results, and teach you how to break the fast safely.

Don’t be intimidated by extended fasting. It’s not so bad and a great opportunity to lose body fat, reset your hormones, and learn valuable lessons in the process. 

3 Day Fast Ryan and Alex Duo Life

how to do a 3-day fast

We’ve done some crazy things in our lives, but this was by far the craziest: fasting for 3 days.

We ate nothing and just drank water, tea, and black coffee for 72 hours. The most surprising part? We felt amazing throughout. Sure, it was a challenge, but it was manageable for us and the results were incredibly motivating.

You can do it too. Even if you’ve never missed a meal your entire life or can’t imagine a day without breakfast, we’re here to tell you that it’s possible.

We have been researching and self-experimenting with fasting since 2018. The benefits are long-lasting. You’ll see immediate benefits like weight loss, but the really good stuff is harder to measure, like prolonged longevity and reduced risk of cancer.

A 3-day fast is the perfect opportunity to get these benefits. Why? Three days is considered the maximum for a DIY water-only fast without needing medical supervision or supplements.

For additional, well-researched content backed by personal experience, check out the articles on our fasting page.

Our History Fasting

Our story with fasting begins a few years ago when I had reached my last straw with Ryan…

“I will not let your stupid hunger ruin my vacation!”

Ryan and I were spending a weekend in San Antonio, and I had the whole day planned with things to do and places to go. But, every two hours, Ryan became cranky, irritable, and complained that he was hungry.

As I stared angrily at him after he asked for the millionth time to eat, he just stared at my purse and asked if I had a snack for him in there. Ummm… no, you’re not my toddler.

Thankfully now, Ryan’s hunger no longer controls him (or me). Ever since he began sleeping more and intermittent fasting accidentally, his hunger no longer rules him.

Given our success with intermittent fasting, when Ryan suggested we do a 3-day fast, I was on board. We already knew of tons of friends who fasted for both health or religious reasons, all to great success. One of our ultramarathon runner friends even continued to log a marathon a day even during the month of Ramadan. I was ready to try it.

Now, a few years later, we’ve incorporated extended fasting into our routine, about once every 4-6 months. We view it as a powerful detox tool that not only betters our health, but empowers our eating choices.

We’ve also received hundreds of emails, comments, and anecdotes over the years, and tried new fasting products, like ProLon’s 5-Day Fasting Mimicking Diet. We’ve read more books, reviewed the latest research, and will share everything that we’ve learned right here.

Good luck and enjoy!

How Do You Define Fasting?

First of all, we need to make one thing clear: fasting is not starvation.

Fasting is voluntary and you can end it anytime. In the book, The Complete Guide to Fasting, by Dr. Jason Fung and Jimmy Moore, the authors likened fasting to a recreational run, instead of starvation which is like running from a lion to save your life.

Starvation is brought on by war, famine, and similar dire circumstances outside of your control. Fasting is voluntary to achieve therapeutic, spiritual, or health benefits.

In fact, many readers have shared that they called it quits halfway through due to feeling weak or lightheaded. That’s perfectly OK! Again, this is voluntary and you have to listen to your body.

Fasting is a tool that can be used for cancer prevention, weight loss, type 2 diabetes, increased focus, and toxin reduction.

Generally, to stay in a fasted state, you don’t want to eat anything that exceeds 50 calories*. In the 3-day water fast described here, you’ll be consuming 0 calories. Total.

*One small note: Decades of science has created a new type of fast called “fasting-mimicking diets.” We discuss this thoroughly in our review of a product called ProLon, but the premise there is that you can eat specially-formulated foods that “trick” your body to stay in a fasted state, despite eating 700-1100 calories a day for 5 days.

We’ll talk more about that below too, as it’s another viable, extended-fast option if a water fast is too challenging.

What Is a 3-Day Water Fast?

It’s nearly exactly what it sounds like. Consuming nothing but water for 72 hours. Think of it as a 3-day water diet.

I say ‘nearly’ because there is the option to consume a few things other than water. More on that soon.

The real question is, “Why would anybody in their right mind want to fast for three days?” If you’re thinking of weight loss, you’re thinking too small. The benefits are astounding and the feeling is truly empowering.

The 3-Day Fast Benefits

For years, Ryan and I have read about the health benefits of fasting. Your 3-day fast benefits will include:

Neurological boosts

  • Improved memory
  • Better concentration

Decreases risk of disease

  • Reduced inflammation
  • Reduced blood pressure
  • Lower heart rate
  • Less fatty liver
  • Decreased atherosclerosis
  • Cancer prevention

Aids in weight loss

  • Increased insulin sensitivity
  • Increased lipolysis (fat-burning)
  • Decreased leptin (better control of hunger)

Promotes longevity

  • Anti-aging effects
  • Autophagy (cellular cleansing)


Furthermore, fasting for even longer leads to even more benefits, something we touch upon in our article, ‘Stages of Fasting By Hour.’

For example, Dr. Thomas Seyfried, a professor at Boston College, found in his treatise, Cancer as a Metabolic Disease: On the Origin, Management, and Prevention of Cancer, that a yearly 7-day fast could kill off abnormal and pre-cancerous cells.

Any fast going into 4-5 days also sees stem cell production and immune system regeneration.

So while we’re asking you to stop at 72-hours/3-days here unless you have a doctor’s supervision or are following a fasting-mimicking diet, you’ll still receive immense fasting benefits.

We just wanted to share with you that the longer you fast, the more benefits you’ll earn if you’re wondering if your current intermittent fasting schedule is doing enough.

how to Prepare for a 3-day water fast

Always the engineers, we prepared for our 3-day fast by researching and reading books about fasting written by doctors.

We wanted fasting to feel natural and something that could be done on a whim. No binge-eating the night before.

Ryan and I read several books on fasting beforehand and learned a few key water fasting tips. Following them will help you plan your 3-day fast and teach you how to make your fast successful.

To gain a well-rounded perspective of 3-day fasting, we read books by doctors who promote a high-fat animal-protein diet, a high-fiber vegetarian diet, and diets somewhere in between. 

Below are three incredibly fast-cinating books that we highly recommend. 

Additionally, we created a free 3-Day Fasting Guide to help you plan, track, and properly break your fast. If you love structure like we do, feel free to download the guide below. 

If this article (or the 3-Day Fasting Guide) helps you out, please pay it forward by sharing your experience or questions in the comments section. We prefer that to email because the discussion helps all future readers!

3-Day Fasting Guide Printable PDF Ryan and Alex Duo Life

3-Day Fasting Guide (Printable PDF)

Download and instantly access the 3-Day Fasting Guide including the following.

  • Step-by-step checklist for before, during, and after your successful 3-day water fast.
  • A journal to track your experience and hunger levels.
  • Critical reminders and a suggested hour-by-hour meal plan to break your fast.

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

Steps to Prepare for an Extended Fast

Here is a pre-fast checklist to get the most out of your fast.

1. Decide how long you will fast.

While intermittent fasting has become incredibly popular, there are few limits on what constitutes the right amount of time to fast for health purposes.

Much changes from person to person. Depending on your diet, insulin sensitivity, and exercise level, it could take between 12-36 hours to “flip” the metabolic switch, something we discuss more in our article on the health benefits of IF.

It took us 56 hours to flip our switch during this 3-day fast. For a better understanding of the 5 stages of fasting by hour, see our explanation and metabolic data from a recent 24-hour fast

And when I say there is no right amount of time to fast, it truly has no upper limit. The longest fast ever recorded was in 1965 by a Scottish man, Angus Barbieri, who took daily vitamins with zero-calorie drinks like tea, coffee, and water.

Obese at 456 pounds, he fasted under doctor supervision until reaching his goal weight of 180 pounds. Which he achieved in full health, 382 days later.

Nowadays, most extended fasts are 7-14 days. The people who opt to do these long-term fasts are usually fighting obesity, fatty liver disease, insulin resistance, type 2 diabetes, or other metabolic diseases.

Shorter fasts of up to 1-3 days are seen more among people looking to detox and lose moderate weight.

When undertaking a fast longer than 3 days, it is imperative to have some clinical supervision or to follow a fasting-mimicking diet.

2. Drinking coffee and tea during a 3-day fast is fine.

Other acceptable drinks for a healthy fast include tea (with the exception of yerba mate since it’s high in carbs) and coffee. Feel free to add a slice of lemon, but avoid milk or sugar.

Even zero-calorie sweeteners like stevia should be avoided, as it isn’t in line with the detox mentality. Zero-calorie soda is out of the question. If you still drink soda, you need to quit cold turkey yesterday.

For those of you who are caffeine dependent (like we were) this is great news since you don’t have to worry about nasty caffeine withdrawal headaches.

3 Day Fast Ryan and Alex Duo Life Water Fast

3. You can have more than just water during a 72-hour fast.

For fasts longer than 3-days, consider supplementing with electrolytes to maintain mineral levels. This can be done with zero-calorie electrolyte drinks, bone broth with sea salt, or miso soup for vegetarians like us.

Since our fast was only three days, and studies showed that mineral levels aren’t affected up until then, we didn’t consume any electrolytes.

An absolute fast, usually done religiously, means nothing is consumed. However, the studies we read highly recommended drinking water because dehydration only harms and complicates your fast.

4. A 3-day water fast takes longer than three days.

A 72-hour fast doesn’t take just 3 days, it takes 4.5 days. That’s because you want to reintroduce foods carefully to avoid stomachaches afterward.

The rule of thumb is to take the number of days you fasted and divide it by two. That’s the number of days you should still be careful with eating, particularly with simple carbohydrates, before resuming your normal diet.

Instead of breaking our 72-hour fast by feasting, we ate this. It doesn’t look very exciting but the flavors were incredible! We’ll take a deep dive into how to break a 3-day fast later on. It’s more important than the fast itself.

3 Day Fast Ryan and Alex Duo Life Breaking the Fast

5. Don’t eat a final meal heavy in carbohydrates.

The purpose of the fast is to drop insulin and glucose levels to kick your body into ketosis (your fat-burning stage). Eating a whole bowl of pasta will prolong the time it takes for your insulin levels to deplete and delay your good results.

6. Let family or roommates know you’re fasting.

If there are other people in the house, let them know you’re fasting. While you’re hopefully not cranky, they should be aware and therefore prepare their food more privately while you’re fasting.

Our fast took place while staying with my parents, so we went for walks while they ate dinner.

7. Start your fast on Thursday after lunch or dinner.

If you work from home and have a flexible schedule, this doesn’t matter. If not, consider having your second and third days of fasting — most likely your hardest — over the weekend when you’re not working.

For us, our 3-day fast did derail our life. We didn’t sleep so well after flipping our metabolic switch, we ended up pausing our workouts, and many, many readers have commented that they had to stop the fast partway through due to lightheadedness and weakness.

I’m not saying this to scare you, and I applaud everyone who had to call it quits because they listened to their body.

All I’m recommending is to plan accordingly and probably make sure you’re not going to be in the middle of your work week or in an especially hectic period. This 3-day fast is not a walk in the park and will take some effort.

8. Consider running bloodwork before and after.

To make the most out of your fast, it would be nice to compare your blood sugar levels, cholesterol, ketones, etc.

For Ryan and me, we simply measured our weight, rated our hunger twice daily on a scale from 0-10, and tracked our sleep and heart rate through our Apple Watches.

9. Prepare to measure progress.

In retrospect, we would have also measured our waistline and taken body fat caliper measurements. It’s best to track your 3-day fast weight loss with more than just the scale.

Next time we schedule three days fasting, we will be prepared to gather all the data with the following gear.

Also, while it was clear for us when we flipped our metabolic switch, that’s not the case for everyone. Next time, we look forward to monitoring our CO2 levels with our Lumen metabolism trackers.

And, since it’s best to know exactly how your body is responding to your fast, we highly recommend this Ketosis Home Urinalysis Tester Kit. For $8, you can get 100 test strips which will let you know your ketone level in 60 seconds.

Shop our recommended gear below. If you don’t have an Apple Watch or a FitBit that tracks your sleep and heart rate, buy the Mi Band on the below shopping list without even thinking. It’s the best $40-50 ever spent.

Our 3-Day Fast Experience, Results and Breaking the Fast

In this section of our 3-day water fast report, we’ll share all the data and details of our fast. Here is what we’ll cover. 

  • An hour-by hour water fast experience – A journal about what it was like and our results.
  • The 3-day fast before and after results – Graphs summarizing our weight loss, hunger/difficulty rating, and sleep data.
  • What we did to break our fast – this is a critical step and we share exactly what we did and why. 

Let’s begin!

our 3-Day water fast Hour-By-Hour Experience and results

Day 1

Alex’s Weight: 107 lbs. 
Ryan’s Weight: 169 lbs. 

Nervous Excitement

After a normal day of eating ending with pizza (probably not the best choice) and salad for dinner, we began our fast at 8 PM on Saturday. We went to bed nervous but excited.

Our first night of sleep was perfectly normal since we ate dinner normally and began our fast at 8 PM.

The next morning, we kept to our typical schedule and exercised. Ryan and I did a tough workout for 30 minutes to P90X3. After that, we started our workday and made sure to drink lots of water.

It’s up to you if you want to  exercise during an extended, 3-day fast. On our typical day following a 16/8 IF plan, we work out in the morning and break our fast 1-2 hours after. Therefore, working out on an empty stomach is our norm.

If you’ve never tried fasted workouts, we recommend relaxing and focusing on your water fast. However, intermittent fasting and morning workouts can be an incredibly useful tool in your healthy living toolbox. Make a note to try them out after you finish your fast.

Our First Hurdle

Halfway through the day, I started getting a bad headache, which I associated with my daily coffee habit. While I was hoping to drink water only for the 3-day water fast, there’s no sense in battling hunger AND a throbbing caffeine headache.

When Ryan admitted to having a dull headache as well, I made us each a cup of black tea and our headaches went away within thirty minutes.

The rest of the evening was surprisingly normal, and we even took a walk at night while my parents ate dinner.

24 Hours Checkpoint

On a scale from 1-10 for hunger, Ryan felt 6/10 for hunger and a 2/10 for me. It’s crazy, but we weren’t hungry! Our stomachs haven’t been growling and we felt surprisingly satiated after a cup of tea at 4 PM.

But, we weren’t holding our breaths. From what we’ve heard, Day 2 is usually the hardest on a 3-day fasting journey. This seems to ring true even during a longer 7-day or 14-day fast. So, we went to bed unsure of what was coming the next day.

Below is our sleep data, showing a typical night’s sleep for us.

3-day fast sleep data night 1 Ryan and Alex Duo Life

Day 2

72-hour fast weight loss results:

Alex’s Weight: 105 lbs. (down 2 lbs.)
Ryan’s Weight: 162 lbs. (down 5 lbs.)

Our Second and Last Hurdle

Sleep. Many fasters have trouble sleeping. That was never us while following a 16/8 intermittent fasting plan, however, beyond 24 hours was a different story.

Ryan was too energized to sleep and he could only get comfortable on his side, in a fetal position, because his stomach ached on his back.

We both woke up feeling restless, although our Pillow sleep tracker app showed us that it was a typical night of 8.5 hours of sleep.

When Does This Get Hard?

After a 30-minute dynamic stretching workout, we brewed a cup of tea and started our workday. We felt focused, comfortable, and knocked off item after item on our to-do lists.

We hydrated consistently, and in the evening, we once again took a walk while my parents ate dinner and reveled in having extra hours to hang out instead of cooking or washing the dishes.

48 Hours Checkpoint

On a scale of 1-10 of hunger, Ryan felt 4/10 and a 3/10 for me. Honestly, not much had changed in the past day. We went for another walk and watched a movie before bed.

We didn’t experience hunger pangs or any physical or mental fatigue. The only thing we both noticed was that we would occasionally get light-headed when we stood up and started moving too fast.

Below is our sleep data for the second night of our 72-hour water fast.

3-day fast sleep data night 2 Ryan and Alex Duo Life

Day 3

72-hour fast weight loss results:

Alex’s Weight: 103 lbs. (down 4 lbs.)
Ryan’s Weight: 162 lbs. (down 7 lbs.)

Boom. There It Is… Hunger

At 9 PM, hour 49, both of our stomachs started grumbling. For the first time in days, we both felt hungry at a 7/10. It wasn’t painful or a bite-your-head-off type of hunger, but it was noticeable.

This must be what everyone had talked about when they said it gets hard. On top of that, my legs felt a bit achy and we overall felt a bit depleted.

We went to bed restlessly but luckily the majority of the hunger pangs happened while I was asleep, because 5 hours later…

What Should Happen During a 72-Hour Fast

At hour 56, just before 4 AM, I woke up. I couldn’t figure out why I woke up until I realized that my heart was racing.

My whole body reverberated with each beat and I checked my Apple Watch to see that my heart rate was at 95 bpm (beats per minute).

Just minutes before when I was sleeping, it was at my typical 55 bpm. My metabolic flip had switched. Ketosis had been reached. My mind felt sharp, clear, and wide awake.

I was no longer hungry. The glucose in my bloodstream must have run out, and my body switched from burning glucose to burning fat. My brain was running on ketones, and adrenaline kicked in.

This is what should happen when you know how to fast for 3 days and you follow the rules.

When reaching a fasted state, insulin plummets while adrenaline (for focus) and human growth hormone (to maintain muscle) skyrocket.

This happened so that our ancestors would be on their top game to hunt and find food. I had finally reaped the rewards of my fasting.

The next day, we filtered through our Apple Watch heart rate data and found that Ryan flipped his metabolic switch while lying awake reading a few hours earlier.

3-day fast metabolic switch Ryan and Alex Duo Life
Sleep Was Not Happening

Since I was wide awake, I grabbed my book to start reading in bed and accidentally woke Ryan. Like me, he was wired and no longer hungry.

But, unlike me, he hadn’t fallen asleep until 2 AM because his peak hit at 11:30 PM a few hours before.

After a few hours of reading, my heart rate finally slowed and I became drowsy. We both fell asleep again at 6:30 AM and woke up around 10 AM.

Easy Street

Throughout the rest of Day 3, we both felt no hunger, a 1/10. An overall feeling of easy wellness and energy came over us. We kept ourselves busy and Ryan even did some tough manual labor in the heat.

We went for a long walk around my hometown’s public gardens and farm before coming back to finally eat food and finish three-day fasting.

3 Day Fast Ryan and Alex Duo Life Ryan Exercising
72 Hours Checkpoint

We made it! Unbelievably, we had gone without food for 72 hours and it felt amazing. We could have continued longer, but mentally we were ready to eat as that deadline had been on our minds since hour 1.

Plus, it had felt unsocial while staying with my parents and we just missed the whole ritual of sitting down and eating. But, we had done it and knew that we could do an even longer fast next time if we wanted.

Below is our sleep data for night 3. As you can see, this was a very restless night’s sleep for both of us.

3-day fast sleep data night 3 Ryan and Alex Duo Life

Final results: 72-hour fast before and after

3-Day Fast Weight Loss

Alex’s Final Weight*: 101 lbs. (7 lbs. lost)
Ryan’s Final Weight*: 160 lbs. (9 lbs. lost)

*A note about weight loss on a 3-day fast: On average, 0.5 lbs. of fat will be lost per day during fasting. One pound of fat is 3,500 calories, which is about double the number of calories you likely burn on a typical day (perhaps closer to 1 lb. for Ryan who burns 2,500+ calories a day).

The rest of the weight loss you see is water weight. This number was corroborated by numerous studies we read as well.

The below graph shows our 3-day water fast weight loss results. This result was similar to our weight loss during on ProLon 5-day fast study, where Ryan lost 9.6 lbs. and Alex lost 5.4 lbs.

3-Day Water Fast Results Weight Loss Chart Ryan and Alex Duo Life

The next chart is a summary of our hunger rating. As you can see, Ryan had hunger spikes around dinner time for the first two nights. The second day was the hardest.

Then, both of us were not remotely hungry by night 3, at the end of our 3-day fast.

3-Day Fast Hunger and Difficulty Rating Results Ryan and Alex Duo LIfe

Lastly, here is a graph showing our sleep scores during the 3-day water fast. Insomnia is very common during water fasting, and (as you can see) we got crushed on the third night. 

3-Day Fast Sleep Data Ryan and Alex Duo Life

If you take a look at the results from our 5-day fasting mimicking experiment, you’ll see that this was a much different story. We experienced no insomnia. But, we’ll talk more about water fasting versus fasting mimicking later on.

how to break a 3-day water fast

We knew to break our fast carefully to avoid stomach aches or refeeding syndrome. After a lot of research, this is how we did it.

How Much To Eat While Breaking Fast?

Some research says to eat around 500-800 calories on your recovery days (or about half of what you normally consume). We ate more than that, but made sure that everything was fresh, nutritious, and still in a small portion. And we felt great.

Once again, your recovery days should last about half the length of your fast, so we were careful for 1.5 days after our 3-day fast.

Hour 72 – Miso Soup

Ryan and I started with cups of miso soup. Bone broth with sea salt is also a popular option, but as vegetarians, we went with miso soup which we made from miso paste found at our grocery store. It was salty and oh so delicious.

3 Day Fast Ryan and Alex Duo Life Miso Soup

We highly recommend breaking your fast gently with something like miso soup or bone broth. Next time we do a 3-day fast we’ll also use the electrolyte hydration powder on the below shopping list. This supplement has been recommended by many of our readers.

Below are useful foods and supplements for during and after your 72-hour fast. 

Hour 73 – Vegetables and Guacamole

An hour later, we started breaking our 3-day fast with solid food. We made a small salad with cherry tomatoes, cucumbers, fresh parsley, olive oil, a squeeze of lemon, and salt and pepper.

On the side, we had a few scoops of guacamole. This meal focused on healthy fats and fresh, non-starchy, and non-cruciferous vegetables. We avoided simply carbohydrates so that our insulin wouldn’t spike and undo all of the hard work we had done.

We also avoided dairy as it’s hard to digest. After a fast, the number of digestive enzymes in your body decreases, so you have to start easy.

3 Day Fast Ryan and Alex Duo Life Breaking the Fast Salad

Hour 75 – Breakfast Before Bed

Since we felt great, we were ready to introduce another small snack before bed, allowing our bodies to digest all of our newly eaten food.

We ate some typical breakfast foods of an egg, black beans, plantain, and more guacamole. As we hoped, this helped ensure a restful night’s sleep.

Hour 87 – Breakfast Smoothie

We started our day carefully with a vegan vanilla Shakeology smoothie, made from fresh blueberries, homemade cultured milk kefir, peanut butter, bananas, and mint leaves.

We also made sure to hydrate to aid in digestion while getting in enough fiber.

Hour 90 – Black Bean Veggie Tacos

Ryan and I still felt great and satiated without any stomach issues. We introduced a few carbs in the form of corn tortillas and had veggie tacos with black beans for lunch.

Hour 95 – Almost Back To Normal

Finally, a celebratory dinner with the family. We ate a home-cooked Greek meal by my mother of spinach spanikopita with a cucumber yogurt soup and a huge lettuce salad.

Our eating was nearly back to normal, but we still passed on the bread and alcohol. This gradual, controlled approach is how to break a 3-day water fast properly.

And Beyond

Once we reaped the benefits of our extended fast and successfully broke our fast for 1.5 days, we slid right back into our typical 16/8 intermittent fasting eating plan.

Intermittent fasting studies show you don’t have to change your diet whatsoever to lose weight. This is amazing news!

However, we’re here to tell you that it is much, much better if you do to receive all of the health benefits. And a healthy diet is essential in our experience. Below, you can download our printable intermittent fasting meal plan.

3-Day Fasting Guide Printable PDF Ryan and Alex Duo Life

3-Day Fasting Guide (Printable PDF)

Download and instantly access the 3-Day Fasting Guide including the following.

  • Step-by-step checklist for before, during, and after your successful 3-day water fast.
  • A journal to track your experience and hunger levels.
  • Critical reminders and a suggested hour-by-hour meal plan to break your fast.

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

Our 72-hour Fast Lessons, Common Questions, and Conclusions

The final section of our 72-hour water fast study will cover the following.

  • Lessons learned (updated with lessons from our 5-day fasting mimicking diet)
  • Common questions about water fasting
  • Closing thoughts on how to do a 3-day fast successfully

Let’s begin.

lessons learned from our 3-day fast

Our fasting experience was eye-opening. These were our biggest takeaways. 

We Can Control Hunger

The hunger never overwhelmed us because hunger doesn’t just grow, grow, grow until you’re ready to eat your own hand.

It comes in waves that get weaker each time. The hunger we felt was the same as when you miss lunch because you’re stuck in a meeting. More often than not when the meeting is over, you’re not hungry anymore.

That’s because the hunger we experience (when not in a war or famine) isn’t when our stomachs are empty. Heck, people say “they’re starving” just hours after their last meal!

Those hunger pangs are hormonal and signals from the brain, not your stomach. Like Pavlov’s dogs, you’re ready to eat because the clock strikes twelve, not because you need the food.

We Appreciate Food And Our Bodies

It was truly incredible to experience what your body goes through during a 72-hour water fast. And that first meal afterward, cherry tomatoes and cucumbers, have never tasted so good!

3 Day Fast Ryan and Alex Duo Life Alex Breaking the Fast

We Easily Survived

Each pound of body fat we carry is 3,500 calories, and when in a fasted state, our bodies learn to tap into that resource and energize itself. And let’s be honest, most of us carry a few (or more) pounds of extra fat.

To give you some perspective, the average body fat in men is 25% and 35% in women. Even an elite, lean marathoner carries around 9% body fat. So, you’ll survive just fine.

A New Tool In Our Toolbox

Ryan and I found fasting to be a great tool in our health arsenal, and it’s a tool that humans have used for thousands of years. Extended fasts or alternate-day fasts can and should be mixed in with a typical intermittent fasting schedule.

It can be something you do every month, depending on your health goals.

As Plato so simply puts it, “I fast for greater physical and mental efficiency.” Fasting does the body well and is incredibly effective. Try it and surprise yourself.

We Prefer Fasting-Mimicking Diets Instead

Ryan and I did this 3-day fast in 2020… but we haven’t done it since and now it’s 2024. Why?

First off, we LOVED this 3-day fast. We have never felt so empowered in our lives and it allowed us to handle our hunger so much better. Nothing phases you after fasting for 3 days and we highly recommend it to everyone!

But, it was a challenge. Our sleep was pretty terrible and it did derail our lives. We missed workouts, had to take it easy, and didn’t socialize. With that and the fact that we became pregnant, had a baby, spent a long time breastfeeding, etc. since 2020, we never did an extended fast again… until last month with a fasting-mimicking diet.

What is Fasting-Mimicking?

One of the books we recommend you to read above, The Longevity Diet, was written by the recognized godfather of fasting research, Dr. Valter Longo. He developed fasting-mimicking diets (FMD) and has run dozens of clinical trials on it at over 18 universities/institutions including the Mayo Clinic with success.

Anyway, he created a 5-day meal kit called ProLon where you eat 700-1100 calories a day BUT your body thinks you’re fasting! This means you can get the benefits of a 5-day fast without any hunger, poor sleep, missed workouts, or grumpy feelings.

Water Fasting Versus FMD

If it sounds too good to be true, it’s not. We documented our full experience and all the data in our ProLon review and found, without any of the hardship, that we lost a similar amount of weight as the 3-day fast, experienced a fully-emptied GI tract unlike our water fast, and revved up our metabolism immensely.

It’s just another option for you, if this 3-day fast experience intimidated you.

If you’re interested in this route, here’s a discount of 20% off with ProLon  using our link and code RYANANDALEX. It was mind-blowing, especially since we’ve already experienced a “true” water fast and know how tough it can be!

common questions about fasting for 3 days

Here are a few frequently asked questions that we were asked while broadcasting our fasting journey on our Instagram page. Have more? Please reference our fasting page or comment below and we’ll get them answered.

Is there anyone who shouldn’t fast?

Men and women have been fasting for millennia for health and religious reasons. Both men and women see similarly great results when fasting, yet there are a few groups who are not recommended to fast by doctors.

Pregnant women and breastfeeding mothers are not recommended to fast, as their mineral intake requirements are higher for themselves and their babies.

Additionally, anyone with a history of anorexia or who is malnourished (often generalized as groups with a BMI of 18.5 or below) should avoid fasting as well.

Finally, people on medication, particularly type 2 diabetics on insulin or blood sugar medicines, should first consult with their doctors to modify the medicine dosages during the fasting period.

For people who take daily medicine with food, consider a 24-hour fast instead so that the medicine can be taken along with your one daily meal.

Will I lose muscle if I fast?

No, studies show that muscle mass will not be depleted when exercise and workouts are maintained.

In fact, weight lifters were some of the first athletes to experiment with fasting and timed eating to reduce body fat and increase muscle mass.

During fasting, human growth hormone levels can more than double, which preserves muscle and strength. Our bodies are smart enough to know that fat burns before muscle.

We will say, though, for fasts longer than 3-days, this is a concern. For example, when we recently did a 5-day fasting-mimicking diet, the ProLon meal kit came with a glycerin drink designed to be easy energy so that our bodies didn’t start cannibalizing our own muscle.

What happens to bowel movements during fasting?

This is an interesting question and one that many people ask since your poop can teach you a lot about your health. It gets crazy how much stuff gets cleaned out. Well, this is a detox after all.

We didn’t personally experience anything out of the normal with the 3-day fast.

However, we know what people are talking about since it happened to us during our 5-day fast with ProLon, but it only happened after Day 3. It felt like everything but the kitchen sink got cleaned out of our guts in the most satisfying way. It was probably only the second time ever (since birth) that our GI tracts got a fresh start!

During longer fasts, expect to go to the bathroom less frequently and continue to drink lots of water throughout to aid in digestion.

Remember Angus Barbieri, the guy we mentioned who fasted for 382 days? His bowel movements happened every 37-48 days. Crazy.

What should I eat to break a 3-day water fast?

What’s interesting about this question is that many doctors have varied, and often opposing, opinions on what foods to eat.

Doctors all tend to agree on broth, soup with cooked vegetables, nuts, non-starchy vegetables like tomatoes and cucumbers, avocados, cultured yogurts, small portions of protein (chicken, fish, and eggs are mostly named), and fresh fruit juices. Berries are also a good choice as they are low in sugar.

Things to avoid include simple carbohydrates, high-sugar foods, alcohol, cruciferous vegetables, root vegetables, and dairy.

What should I eat before a fast?

Fasting should fit naturally into your lifestyle, so don’t overeat and binge before a fast. Ideally, you would eat a high protein, low carb meal to minimize glucose availability to kick you into the fat-burning ketosis stage faster.

How long and often can I fast for health?

There’s no upper limit to fasting, as the longest fast lasted for 382 days with Angus Barbieri in 1965. Also, there’s no “best” fasting schedule, and some research suggests that mixing it up is beneficial for your health.

Just like a good workout program, variety avoids plateau and strengthens the body.

Fasting includes intermittent fasting, alternate-day fasting, and extended fasts over 24 hours. For fasts over 3 days, supplement with electrolytes, bone broth with salt, or miso soup. It’s a good idea to have your doctor supervise a longer fast as well.

Longer fasts (7-14 days) are typically performed by people with large weight loss goals, developed insulin resistance, have fatty liver disease, or who have type 2 diabetes. These are overseen by doctors.

Shorter fasts of up to 1-3 days are seen more among people looking to detox and lose moderate weight.

From our research, fasts under 48 hours can be done weekly while longer fasts can be done every two weeks with intermittent fasting in between.

Should I fast or do a low-calorie diet?

Research shows again and again that fasting is more effective than a low-calorie diet. The thing is, even celery, a nearly zero-calorie food, will increase your insulin levels.

The only way to bring down insulin resistance is to stop consuming foods altogether or to follow a fasting-mimicking diet.

Another problem with a restricted-calorie diet is that it affects your metabolism and can throw hormones out of whack, which is the problem with fad diets.

This doesn’t happen when fasting, which instead provides hormonal benefits.

Low-calorie diets, unlike our calorie approach in our 30-day challenge for sustainable weight loss, are hard and don’t work long-term. You’ll feel like you’re deprived constantly and are tempted to overeat.

Fasting is simple and helps you control your hunger because it controls your hunger hormones (like leptin and ghrelin). 

As the author/philosopher Mark Twain said, “A little starvation can really do more for the average sick man than can the best medicines and the best doctors.”

Will my metabolism slow down from fasting?

Ours didn’t. Studies performed on a 4-day fast found that fasting maintains or even revs up metabolism by as much as 12%. Our experience corroborates this.

While we didn’t have our Lumen metabolism trackers when we did this 3-day fast, we have since done 24-hour fasts and a 5-day mimicking-fasting diet while collecting our metabolism data. Our metabolic health and flexability improved.

Again, fasting allows your pancreas (where insulin is produced) and your body to take a rest to reset, repair, and cleanse.

Experts claim that autophagy (cell regeneration) can start as early as 18 hours into a fast, but maximum benefits are reached around 72 hours. Your metabolism levels should stabilize throughout.

Since we’re on the topic of metabolism, 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.

We’ve used it for months now, and it’s mind-blowing. We discovered that our bodies use fuel completely differently, despite eating all of the same meals. I discovered that my fasting window is much shorter than Ryan’s — something the device helps you figure out.

So if you’re ready to zero in on your fasting skills, the Lumen is the most helpful tech in existence if you have $250 to spare and our $50 off code RYANANDALEX.

Should I fast together with my partner?

Absolutely, yes! Having your partner on the same schedule as you is incredibly beneficial, as there will be fewer temptations around and more accountability and support.

Closing Thoughts on How To 3-Day Fast

We hope the article has helped improve your fasting experience. 

Feel free to download our free 3-Day Fasting Guide to help you plan, track, and properly break your fast.

If, like us, you’re a proud 3-Day Fast survivor, please pay it forward by sharing your experience and tips in the comments section.

Leave any specific questions about 3-day fasting in the comments below. We prefer that to email because the discussion helps all future readers. Thanks!

For general questions about fasting, head over to our Fasting Page.

3-Day Fasting Guide Printable PDF Ryan and Alex Duo Life

3-Day Fasting Guide (Printable PDF)

Download and instantly access the 3-Day Fasting Guide including the following.

  • Step-by-step checklist for before, during, and after your successful 3-day water fast.
  • A journal to track your experience and hunger levels.
  • Critical reminders and a suggested hour-by-hour meal plan to break your fast.

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.

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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 “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.

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