This ProLon review is our experience and results after doing the ProLon 5-Day Program: Cellular Rejuvenation and Metabolic Reset.

As a husband-wife duo, two engineers, and experienced fasters, we wanted to share our unique experiences from two very different people as a case study for others. Ryan and I also had a lot of questions and took meticulous measurements and notes to hopefully answer all of your questions and ours.

Did the ProLon 5-day fast really work for us?

In this ProLon review, we’ll share our day-by-day notes, all of our stats, including weight loss, inches lost, sleep scores, hunger levels, photos, our real-time metabolism measurements, and how we continued to feel in the weeks after the fast.

Plus, we can share a discount code for our readers if you’re interested. More on that below.

Prolon Review Ryan and Alex Duo Life

Prolon 5-Day Fast Program Review

Ryan and I are experienced fasters — both with intermittent fasting and extended fasting like with our 3-day water fast.

We’ve also researched the topic and written about it for years (there’s a whole fasting section on our website for it). We cover everything from fasting meal plans to beginner guides to breaking through a fasting plateau.

Ryan and I are sharing all of this just to say that this ProLon fast review has been on our radar for years. We’ve read the book by the founder, Dr. Valter Longo, who is recognized as the world’s #1 expert in fasting and longevity nutrition, and followed the 18 universities that have performed studies on the ProLon diet.

If I hadn’t been pregnant or breastfeeding for the last two years, we would have done this ProLon fast review a long time ago!

But, anyway, what is the ProLon diet and why is it so interesting?

What is the ProLon Diet?

ProLon is a meal kit based on decades of research on fasting mimicking diets. We committed to the popular 5-day fast.

You’re likely familiar with the many scientifically proven benefits of fasting (anti-aging, cellular rejuvenation, cancer reduction, weight loss, etc.) but, traditionally, this means you need to fast with nothing but water for days on end.

In fact, extended fasts over 3 days aren’t recommended without doctor supervision, yet some of the best benefits happen after Day 3. We write about this in our article, “Stages of Fasting By Hour,” but as a summary, autophagy might not start until the third day, and immune system regeneration and stem cell production not until the fourth.

What ProLon offers is almost like a fasting loophole, a way to get through 5 days of fasting without the pain of not eating. Their meal kit includes the only food you’ll eat for five days — just add water — and you’ll be eating somewhere between 800-1100 calories a day. That’s not bad!

How ProLon works is that each day’s meal packets are formulated to “trick” your body to remain in a fasted state, even though you’re eating things like soups, crackers, protein bars, and olives.

These are the foods you’ll eat each day over three meals and one snack. It’s really, really simple and feels surprisingly normal. Here is what a typical lunch looks like.

Prolon review what a typical meal looks like
Ryan and I chose to do the ProLon 5-Day Fast Mimicking Diet because it’s the only thing like it out there and has the most science, clinical trials, and data on it.

ProLon Fast vs. Water Fasting?

In the past, Ryan and I did a 3-day water fast where, for 72 hours, we consumed nothing but water and some black coffee. While it was manageable, it was pretty tough. In fact, the other day a reader left a hilarious comment that just said, “Day 2, where the F**k am I?”

To put it mildly, we never did it again, despite it being the most popular article on our blog and a pretty mind-blowing experience.

With the water fast, we knew that we had successfully flipped the metabolic switch and were in ketosis, but we battled headaches, dizziness, awful sleep quality, and even aching legs throughout our 3 days of “real” no-food fasting.

Also, we didn’t surpass 3 days of water fasting because with anything longer you’re supposed to be medically supervised. This means we couldn’t get extended fasting benefits like autophagy, deep ketosis, stem cell production, or cellular rejuvenation.

Could a ProLon fast be the solution?

Throughout this ProLon fast mimicking diet review, we’ll compare our results and thoughts versus the water fast to give you an idea of what could be best for you.

ProLon Fast Mimicking Diet Benefits

What are the benefits of completing the ProLon 5-Day Program? While weight loss is one of the easiest benefits to measure, it shouldn’t be at the top of the list.

Lifting weights is a great way to strengthen the outside of your body. The ProLon fast is an excellent way to strengthen the inside of your body. The byproduct of both is weight loss.

For years, Ryan and I have been studying the health benefits of fasting, including:

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 weight loss

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

Promotes longevity

  • Anti-aging effects
  • Autophagy (cellular cleansing)

That’s a pretty impressive list of potential ProLon fast mimicking benefits. Fasting helps you stay younger and improves your brain and body health.

The biggest advantage, which our data confirms, is that we reaped many benefits without the burdens and risks that come with a traditional fast.

Does ProLon Really Work? Is it Safe?

Whenever we tell our family we’re starting another fast experiment, they always worry. 

We’ve completed five multi-day fasts before, both following professionally designed and DIY plans, and many 24-hour fasts. Every single one of them worked. 

Again, the benefits of fasting are scientifically proven. ProLon worked shockingly well for us, and even though it was the longest fast we’ve ever done by two whole days, it was also the most pleasant (by a long shot). 

It was so enjoyable compared to previous fasts, and our results were so compelling, that our family wants to join us next time. My mother keeps asking me when she should do hers next!

Why is the ProLon Fast 5 Days?

ProLon offers a “ReSet 1-Day Kit” and the “ProLon 5-Day Program.”

The five days are a major reason the program works so well. Doctors and nutritionists agree that there are five distinct stages of fasting. We conducted a separate experiment and published an article titled “Stages of Fasting By Hour,” but here is a summary.

Stage 1: Hours 0-4 – digestion begins and insulin levels spike
Stage 2: Hours 4-16 – fat-burning mode starts despite hunger pangs
Stage 3: Hours 16-24 – ketosis ramps up as hormones stabilize
Stage 4: Hours 24-72 – autophagy and reduced inflammation
Stage 5: Hours 72+ – immune system regeneration and stem cell production

The fifth stage of fasting is not reached until days 4 and 5 of fasting. Sure enough, day 4 of the ProLon fast was the most exciting for us!

A popular extended fast ends at 72 hours or 3 days of fasting. This one is common because you generally don’t need to be under medical supervision or supplement with salts or vitamins. But, ProLon doesn’t offer a 3-day program. We’re glad that’s the case.

For us, ProLon was the means we needed to extend our fast well into stage 5 and reap the immune system regeneration and stem cell production in an incredibly safe and easy way.

What Are the Prolon Fast Side Effects and Risks?

Since publishing our 3-Day Fast results and providing our readers with a plan to follow, we’ve helped thousands on their fasting journey.

Even with a 3-day water fast, which in our experience is more difficult, we’ve heard of no severe side effects although a lot of people do quit early due to weakness and fatigue. With ProLon, you won’t get there.

Throughout the five days, you’re getting food, vitamins, minerals, and a special energy drink to maintain muscle mass.

Still, there are a few drawbacks to doing the ProLon fast. The main risks are fatigue, headache, difficulty with concentration, and major food envy. We were fortunate to only experience the latter. If anything, we felt more energized than normal, especially once ketosis hit.

To minimize the side effects, our only recommendation is don’t quit caffeine cold turkey to avoid headaches and just be normal!

Seriously, there’s no need to psyche yourself out! We continued to work, exercise, hang out with family, and spoonfed our toddler all of her meals without losing it.

Why Trust Us

This is an extensive review. Our goal was to provide all the data and information you need to either commit or move on with your life. (And for those of you ready to commit, we have a 10% 20% discount with code RYANANDALEX).

L-Nutra, the “nutrition technology” company behind the diet is leading the way in food and longevity research. While other companies are pouring billions into developing (but mostly advertising) drugs to cure disease, L-Nutra is reinvesting in the science of how to prevent disease with food.

Their innovative food-as-medicine approach, philanthropic history, and scientific backing from prestigious universities have helped them get tons of coverage from huge outlets and blogs.

While we’re just a small blog, we’ve done a ton of work to understand the ProLon diet, measure our results, and share our data as simply as possible. Here’s a snapshot of the data that we’ll analyze in this ProLon review.

Prolon Review and Results by Ryan and Alex Duo Life
Unlike many other reviews, this is not a regurgitation of the company’s homepage or weak answers to frequently asked questions.

Even on Verywell Fit, their ProLon review was very vague and unhelpful. They said their cons were, “Limiting in what you can eat,” and “Not a long-term solution.”

Ummm, yeah…. You’re limited to the food provided and nobody said it was a long-term solution. The inventor himself only recommends doing the fast 3-4 times per year.

Anyway, we’ve completed the program, collected the data, and crafted a comprehensive review. If you appreciate it, please use our 10% 20% discount with code RYANANDALEX so we receive a commission at no extra cost to you.

Prolon 5-Day Fast Program Review

We were expecting the ProLon fast to be really challenging for Ryan, whose normal calorie intake is 2500 calories a day. Twice during the five days, we’d be dropping down to 800 calories a day, and in the best of times, Ryan experiences hanger.

Even for me (Alex), it was a wildcard. I had just finished breastfeeding, which made me notoriously hungry, and we were in an incredibly tempting environment: Hawaii with my parents over the holidays. And if you know Hawaii, the food is the best in the whole country, in my opinion.

Let me also say one thing: Ryan and I are very experienced at fasting. We’ve intermittent fasted for years (apart from when I was pregnant and breastfeeding), and at our most extreme, we even did a 3-day water fast and consumed nothing but water and coffee for 72 hours.

We were super curious about ProLon’s claims that their fast-mimicking diet can “trick” your body like you’re not eating food when you are.

For us, we had never experienced the amazing fasting benefits that only happen after Day 3, such as cellular regeneration and deep ketosis. This was our main motivation.

ProLon Review Contents:

1. Our data-driven results.

As engineers, we wanted to track our weight loss, waistline, hunger, sleep, and metabolism (using our Lumen Metabolism Trackers) numbers. We’ll analyze the results in this section.

2. Our day-by-day experience.

This is our 5-day journey and what you can expect if you commit to the FMD program.

3. Product info, price, pros & cons.

Here, we’ll show you what is in the box, talk about how much ProLon costs, and discuss the pros and cons.

If you have any questions, or feedback, or want to share your experience, we’d love to hear from you in the comments section. Alright, let’s dive into our data-driven ProLon results.

Our Prolon Fast Results (Data-Driven)

We tracked our weight, waistlines, hunger levels, sleep scores, and even real-time metabolism burn (ie. fat burn vs carb burn with our Lumen metabolism trackers).

ProLon worked even better than expected in five ways.

1. Weight loss – It was significant. 
2. Fat burn – Our bodies were in the zone!
3. Cleansing – Bye-bye waste. 
4. Sleep – Was incredible!
5. Hunger and irritability – Minimal. 

Okay, let’s move onto the graphs, photos, and results for each.

1. Weight Loss Was Significant

The weight loss and inches loss were significant. Especially considering that both Ryan and I didn’t have excess weight to lose. And the best part was that our muscle mass did not decrease, despite the calorie restriction.

Ryan’s starting weight: 165.8 lbs.
Alex’s starting weight: 106.2 lbs.

Here are our day-by-day ProLon fast weight loss results. Ryan lost 9.6 pounds and I lost 5.4 pounds.

We’re sharing our numbers in full transparency so you can see how ProLon affected us, and maybe make a comparison to yourself. Of course, all bodies are different, which is why we’re excited to share both of our experiences with you. 

Prolon review weight loss results by day for ryan and alex

Considering we were able to eat food during this fasting program, based on our experience with how we both lose weight and our past results with fasting, this was huge.

Seriously. Huge and impressive. Someone as petite as me or as lean as Ryan can’t lose weight like that in 5 days, all done safely and without much effort. And, of course, the biggest benefits are immeasurable, like cellular health and longevity.

Ryan’s ProLon Fast Before and After Photos

We were also happy to see that the weight loss occurred in our problem areas. Let’s start with Ryan’s before and after photos.

Prolon fast review before and after photos

Ryan’s biggest problem area is his belly. As you can see in the before and after photos, his stomach flattened out considerably. He attributes this to some fat loss, a lot of cleaning out his digestive tract, and a healthier, less bloated gut.

All of these photos were taken at the same time of day, right in the morning, before eating anything.

Prolon review Ryan's before and after photos
Alex’s ProLon Review Before and After Photos

As you can see in my ProLon transformation photos, I am more slim and I lost a bit of the pudge. This was not a surprise because I was steadily burning fat during the entire 5 days. More data on that soon.

Prolon diet review before and after photos

The most significant ProLon weight loss is seen in my back, which is where I have always carried my excess weight. See the below before and afters.

Prolon review Alex's before and after photos

2. The Fat Burn is Real

People always ask us about fat burn during fasting. It’s a good question because you don’t want to deplete your hard-earned muscle.

Well, the results are in. For the five days straight, Ryan and I were burning fat, as confirmed by our Lumen metabolism tracking measurements. During Days 3-5, we knew we were in ketosis by the jitteriness/energy flow we felt.

Here is our morning fat burn data from our Lumens. On average, Ryan was burning 89% fat upon waking up and I was burning 93% fat. Impressive! Yes, you lose fat, not muscle, on ProLon.

Prolon results for metabolism and fat burn
Another data point that showed significant fat burn was our waistline measurements. Since the ProLon fast mimicking diet claims to target primarily visceral fat, we took our measurements 1 inch below the belly button.

Ryan lost a total of 2.5 inches and I lost 1.5 inches from my waist. Ryan attributes the majority of his inches lost to the digestive cleanse he experienced. More on that next.

Prolon fast results total inches lost waistline measurement

3. Our Bodies Cleaned House

Other than tracking your metabolism in real time with a Lumen device, your poop tells you so much about your current health.

ProLon was fantastic for our GI tracts. We both had multiple bowel movements that were clearly “cleaning everything out but the kitchen sink” via major detox. This is something we never experienced before with our 3-day water fast and we both felt great.

We won’t dive into too many specifics, but these poops were not normal (And yes, we monitor our poop closely). It was clear that our bodies were in cleaning mode. On the evening of day 4, Ryan shared with me that he “must have pooped at least 2 pounds today.”

Sorry for sharing, but it says a lot about what your body is doing during the ProLon fast. We think you should look forward to it!

4. Our Sleep was Perfect

But the unsung hero of all is… sleep. Didn’t think we’d say that? From our experience doing a 3-day water fast, we know that fasting can take a huge toll on your sleep. Even intermittent fasters can have trouble sleeping.

This is unfortunate because whatever focus and mood benefits you get from ketosis are offset by crappy sleep. With ProLon, we slept so well, and that can’t be underestimated.

Below is a graph of our sleep scores from the 5 nights. We both averaged 92% sleep quality through our Pillow sleep app.

ProLon 5-day fast mimicking diet review sleep benefits and results

Both Ryan and I averaged a 92% sleep score during the fast, which is normal for us when our baby sleeps through the night!

Our three-day water fast was a completely different story. And there was no baby at the time! During that fast, Ryan averaged a 66% sleep score and my average was 76% sleep quality.

The insomnia was real! Take a look at the below sleep charts (orange means awake) comparing night 3 of each fast. I can tell you that operating off a 42% sleep quality score during the water fast was awful.

That’s why we recommend you to start a 3-day water fast on a Thursday so you’re not at work for Days 2 and 3 (Saturday and Sunday) when you’re downright miserable.

With the ProLon fast, you can start whenever you want. You should feel normal.

Prolon review and results night 3 sleep comparison prolon versus water fast

5. Hunger (Difficulty) was Low

Finally, and best of all, we felt great during the 5-day program. We weren’t hungry or irritable, and we continued with light workouts.

I can’t say that it was “easy” because we were tempted by everything my parents cooked and still had to feed our toddler. But it was manageable. You could absolutely do this during the work week without issue.

We tracked our hunger rating six times daily on a scale from 1-10. Below is a graph showing how our hunger tracked during the ProLon fast. In retrospect, it’s more like a difficulty rating rather than just a hunger rating.

As you can see, the trendlines show that the fast became increasingly difficult for Ryan and increasingly easy for me.

Prolon fast mimicking diet review how hard is it

In the below graph, we compare our hunger from the ProLon 5-day fast with our 3-day water fast. In a word, we were far hungrier when we fasted without food. I know, duh!, but we were also plagued by headaches and lightheadedness with the no-food fast.

With ProLon, we felt really good and I feel like we missed the idea of eating normally than actually feeling hungry. With the water fast, we were just hungry.

How hard is the Prolon fast compared to water fast
So that’s the main bulk of our measurable data from the ProLon fast. Was it what you were expecting?

It was actually a surprise to us. We thought it would be much more challenging and had worried about our sleep.

What also impressed us was that our weight loss and inches lost were fairly linear and showing progress every day. This motivated us to keep going.

If you’re ready to see what happens for yourself, we have a 10% 20% discount with code RYANANDALEX and would love it if you could track your results and share them with us in the comments!

Our Day-By-Day Experience During the Prolon FMD Program

In this section, we’ll share our day-by-day experience with the ProLon 5-Day Fasting Program. If you’ve never done it, this is what you can expect.

Or, maybe you’ve already started your ProLon fast and you’re wondering what others have experienced. If that’s you, feel free to share your unique experience in the comments section.

What happens during each day of the fasting plan? Here is our detailed journal.

Day 1 – Transforming to a Fasting State

Opening our boxes for the first time, it’s apparent how well-thought-out and organized ProLon is. The meal plan was clear and we followed it exactly (you don’t have to).

Prolon Review what comes in the box
It was so easy, and I could see this being really simple for someone having a normal week at home, with the benefit of not needing to cook or go grocery shopping.

Throughout the five days, you’ll mostly be eating protein bars, drinking soups, and taking supplements. Sometimes, there’s a snack of crackers or olives. It’s repetitive, but the soup flavors change daily and they’re actually quite good.

The only thing we stray from is that, ideally, ProLon is done without coffee. For us, that’s not really an option if we want to avoid our caffeine-dependent headaches, but we actually cut down a lot for this Prolon review and consumed about 40mg of caffeine worth of coffee every day.

Day 1 By the Numbers:

Ryan lost 3.2 lbs and Alex lost 1.8 lbs., with the scale indicating it was exclusively fat.

Today we experienced some of our biggest hunger pangs (Alex at a 5 out of 10 in the afternoon) as our bodies adjusted to 3 meals a day with 1 snack. Surprisingly, Ryan was even keel, rating his hunger somewhere between a 1 to 4 out of 10 the whole day.

Alex’s metabolism data showed an average of a 68% fat burn and 32% carb burn over ten measurements, taken about every 1.5 hours. Ryan clocked in at a similar daily average of 68% fat burn and 31% carb burn for the day.

Overall thoughts on Day 1:

Pretty easy, we went about our normal day, and barely experienced any hunger pangs. The food was tasty enough, and while it’s always a bit hard, we weren’t overly tempted by our toddler’s salmon teriyaki dinner.

Bowel Movement? Yes for both.

Day 2 – Fat Burning & Ketogenesis

This was our first 800 calorie day, so we basically cut out the crackers and olives from the day before. Once again, the soup was pretty tasty, but we decided to torture ourselves at night by going to our building’s holiday party.

Platters upon platters of fried noodles, pulled pork, holiday cookies, and free-flowing champagne covered the tables. Luckily, our daughter wasn’t too hungry and instead, we stood by the band and danced. But… it wasn’t fun and it made us appreciate food more than ever.

Day 2 By the Numbers:

On the morning of day 2, after a restful night’s sleep, we woke up without any hunger, listing a 1 out of 10 for a hunger rating for both. We were also solidly in fat burn mode, with our Lumens telling us we were burning 95% fat and 5% carbs each.

Stepping onto our smart scale, we saw the pounds slide off, but maintained our muscle composition and water percentage. Ryan lost 4.2 lbs and Alex lost 3.2 lbs. after Day 2.

Pretty amazing because, again, we were already extremely lean and didn’t have weight to lose in the first place. After all, we had just finished a marathon days before.

Our hunger today? Non-existent. Over five hunger ratings taken every three hours showed Ryan never breaking a 4 out of 10, and Alex never surpassed a 2 out of 10! So, this wasn’t so hard after all!

Plus, our meals became much more of a ritual. We had a nice sit-down for every meal and snack!

ProLon review day 2 lunch is soup, crackers, olives, supplements, and tea
Overall thoughts on Day 2:

No hunger pangs, excellent sleep quality, and we both felt focused enough to work and exercise. Plus, we experienced a surprising amount of weight loss that our scale told us was exclusively from fat. Cool!

Bowel Movements? Yes for both.

Day 3 – Autophagy Cleanup State

Day 3 of our ProLon experiment turned out to be our best day yet. We were feeling strong and focused. Ketosis was in full swing for the two of us, which we sensed as a jittery/energy-flow feeling.

As I watched my parents running back and forth to the grocery store, it’s so nice to not think about grocery shopping, cooking, or clean up at all — something that takes up 8 hours of our week normally.

I could really see this being an awesome thing to do when on a business trip to somewhere with unappetizing food, or for a full week in the office. I didn’t realize how much food prep weighs on me sometimes.

The hardest part? Being around food. Today my dad put Ryan in charge of cooking a loaf of bread. The smells were torturous.

Prolon fast review day 3 experience and results
Day 3 By the Numbers:

Ryan and I awoke to great sleep scores from our Pillow app: a 88% for Ryan and 89% for Alex.

This is a HUGE win, because our biggest gripe about our previous 3-day water fast was our astoundingly horrible sleep quality. With Prolon, we had avoided this completely.

Plus, once again, we both awoke to no hunger at all — another 1 out of 10.

Again, the weight loss continues, with our smart scale indicating that we’re burning fat. Our Lumen metabolism tracker confirms this too. On average, Ryan sees a 63% fat burn with 37% carb burn. Alex sits at 83% fat burn and 17% carb burn for the day.

On Day 3, Ryan lost 5.2 lbs. and Alex lost 4.4 lbs.

Overall thoughts on Day 3:

We felt accomplished and over the hump. The soup packets are part of our routine, and the finish line is in sight. We talk a lot about the meals we want to have when this is over, but our results are great, we’re not hungry whatsoever, and we’re feeling energized by ketosis and great sleep.

We feel like we could continue this ProLon fast forever.

Bowel Movements: Alex yes, Ryan no.

Day 4 – Cellular Rejuvenation

The days start melting into one another because everything is surprisingly normal. Until shit hits the fan.

Okay, it’s a bit gross but the point of this ProLon review is to share everything…

On Day 4, we both have incredible bowel movements that crap out everything. This is the stuff that fasting dreams are made of. Seriously, people strive to get to the point where they feel like their body has fully detoxed and unloaded the last crap of the crap, so that you can start fresh.

This happens to both of us today — something we only discover when chatting about it at night. Verbatim, Ryan tells me he crapped 2 lbs. Okay, EWW. But congratulations!

This is a big win for Ryan who has battled GI issues for decades. We’ve done several 3-day fasts and never experienced this. It was so satisfying and interesting. The benefits of the longer, 5-day ProLon fast mimicking diet were here!

Prolon fast mimicking diet review day 4 experience

Even though olives weren’t on today’s lunch menu, our mealtime selfie was a happy one because we both had poops of a lifetime.

In the evening, we felt like we could keep fasting like this for days and days longer. We capped the night with strong sleep scores and felt like we were sliding into deep ketosis with excellent focus, endless energy, and no hunger pangs.

Day 4 By the Numbers:

On the fourth day of our ProLon FMD review, Alex rated her hunger at the highest in the afternoon as a 3 out of 10. Ryan was a 5 out of 10. Not so bad for almost 100 hours of fasting! By day 4, Ryan had lost 8.2 lbs. and Alex lost 4.6 lbs.

Our metabolism scores continued to categorize us into fat-burn mode. Over the nine measurements we took throughout the day, Ryan averaged a 59% fat burn with 41% carb burn, and Alex at 67% fat burn and 33% carb burn.

We actually asked Lumen’s scientists to comment about the variations we saw in metabolism, and want to just say that carb burn isn’t bad at all. In fact, a healthy body should be able to choose when to burn carbs (like the carbs you just ate for a meal) or when to burn fat. This is what healthy metabolic flexibility looks like.

Our takeaway from Lumen’s comments is that the measurements continue to show a bit of hunger in the afternoons, but numbers like these, solidly in the fat-burn zone, show that ProLon isn’t kicking our bodies out of fat-burn or ketosis, despite eating throughout the day. In other words, ProLon’s fast-mimicking seems to be working and tricking our bodies.

Here is what a typical week with our Lumen Metabolism Trackers looks like for us compared to the week we tested the fast mimicking diet for this ProLon review.

For your reference, with Lumen, you’re given a grade of 1-5 on the fat-burn scale, a metabolic flexibility score. A score of 1, shown in blue, means high fat burn, and a 5, shown in orange, means high carb burn.

Basically, you can see that ProLon is killing it!

Prolon fast metabolism and fat burn results does it work
Overall thoughts on Day 4:

A day like any other: great sleep, focus, and minimal hunger. Another workout day, too. At this point, we’re very much looking forward to the end and planning our Day 6 meals, but the fast isn’t terribly hard or inconvenient.

Bowel Movements? YES!

Day 5 – Renewal & Change

Our. Final. Day. Woo!

Truthfully, Ryan and I missed food. I was getting tired of powdered soup packets, mainly because eating was now just a necessity and not an enjoyable act.

With that being said, both Ryan and I agreed that ProLon’s fast is far, far easier to do than a water fast, despite being longer. We never experienced hunger, we slept great, and were receiving the same weight loss and metabolism benefits.

While we were excited to finish the fast and had already picked out the sushi restaurant we wanted to eat at the next night, we were also looking at our calendar to see when we could do another 5-day fast with ProLon.

It’s like running a marathon — a bit painful while doing it, but you feel such a huge wave of accomplishment and health that you sign up for the next one right away! On Day 5, we enjoyed a relaxing day at the beach with our daughter.

ProLon review day 5 what it's like
Day 5 By the Numbers:

Our Day 5 weight loss and inch loss statistics were exciting for us.

Ryan lost 9.6 lbs. and 2.5 inches.
Alex lost 5.4 lbs. and 1.5 inches.

It’s pretty spectacular and felt so easy given that we never starved ourselves for it. While this is so much more than a weight loss program, I could see this fast being very popular for the weight loss crowd — perhaps in the days leading up to a big event.

Our hunger levels were low all day, topping out at a 5 out of 10 for Ryan but only a 2 out of 10 for Alex.

Our Lumen metabolism trackers showed us in fat-burn all day too. Ryan averaged another 68% of fat burn throughout the day, and Alex at an even 70% fat burn.

When nighttime came, it almost felt surreal… like this was over! While we weren’t going to eat any food until the morning of Day 6, it was cathartic smashing that final Day 5 box into the recycling bin.

Overall thoughts on Day 5:

There’s not much to report. These days are surprisingly uneventful! More great sleep, excellent fat burn, perfect focus and energy, with almost no hunger. I felt like I could have run a board meeting if I wanted to and not yelled at anyone.

Day 6 – Breaking Fast & Beyond

Waking up — another great night’s sleep with a score of 86% for Ryan and 95% for Alex — you’d think we run straight into the kitchen and eat everything in sight. But no, it wasn’t like that.

We cautiously ate some fruit to break our fast, followed by pancakes with a green smoothie a little bit later, but it wasn’t like there were fireworks! We felt surprisingly… normal. And Alex even felt full and didn’t want to go to the bakery.

I think that’s the mark that ProLon is a healthy diet — it felt like it changed our eating habits for the better. We didn’t want to gorge and binge but instead thought carefully of the great, high-quality meals we really wanted to eat. We felt satiated after smaller meals but maintained our high energy and great feeling.

No stomachaches here, which is something you really need to worry about on a water fast. It was like life continued but with greater enjoyment and thought on what to eat.

Overall thoughts on Day 6:

We didn’t binge eat at all, nor did we have the desire to. Instead, we approached our food thoughtfully and carefully. This fast is excellent for folks who really want to make lasting eating habit changes to kickstart a healthier lifestyle.

We were so impressed. It felt like ProLon could fit seamlessly into our lives, pushing us towards healthy habits while giving us a week off from cooking and cleaning. Plus, while weight loss is always great, we were most excited about our epic bowel movements, detox, buzzing energy, and the empowering feeling like we could conquer anything.

Before we get into the FAQs, let us know what questions you have and don’t forget about our 10% 20% discount with code RYANANDALEX.

Prolon 5-Day Fast Review: Product Info, Price, Pros & Cons

How much does ProLon cost?

No ProLon review is complete without breaking down the pricing options. We’ll take a look not only at the price but at the total value.

ProLon 5-Day Program price

ProLon does run sales periodically (up to an additional 25%), and we’ll update this article when they do.

However, the typical “One Time Order” price is $190 for the 5-Day Program. If you “Subscribe and Save” to have your ProLon supplements or fasting programs delivered every 1 month or every 4 months, you’ll save 10%, lowering the price to $171.

ProLon discount code

For our readers, who have spent all this time following our results and experience, we have a special ProLon promo code: RYANANDALEX.

Make sure you click any link in this article and then add the promo code at checkout to save an additional 10% 20% off. That lowers the price to $154 $136.

If it doesn’t work for some reason, clear your cart and try again.

ProLon value. Is it worth it?

Given our results, the fair price, and immense value, yes. YES. ProLon is worth it. Let’s look at the numbers.

According to GoBankingRates, as of August 2023, the average American spends between $250 and $550 a month on food, which is between $42 and $92 per 5 days. The average person spends $67 on food every 5 days.

According to the U.S. Department of Agriculture, the average person spends 49 minutes preparing food and 33 minutes cleaning up per day. Grocery shopping runs take about 45 minutes.

Even if grocery shopping only happens once a week, the average person spends 7.5 hours cooking, cleaning, and shopping every 5 days. How valuable is your time?

If it’s more than $11.60 $9.20 per hour, then the ProLon 5-Day Program pays for itself. What’s more, is that the 5-day ProLon kit comes with the founder’s book, The Longevity Diet.

We work with thousands of clients each year who are working to better their health. In our experience, the average person is spending $50-$150 a month on something (pills, supplements, Weight Watchers, keto meal delivery, etc.) that’s not helping them reach their goals.

Spending $154 $136 with our discount code (RYANANDALEX) on the ProLon 5-Day Fast Mimicking diet is a no-brainer. 100% worth it.

Where can I buy ProLon?

The lowest price is on their direct website. Plus, their customer service and support are excellent, so we recommend supporting them directly rather than buying from Amazon (which is more expensive anyways).

What comes in the ProLon 5-day kit?

So, what comes in the box? Unboxing and getting started with the ProLon fast is fun and seamless. Everything is perfectly organized and easy to follow.

There are a few key things that come with ProLon, as shown in the picture below. First, there is a box for each day containing all your food and supplements. Next, there are a couple of extra pouches of soup just in case you want to swap one flavor for another.

ProLon review what's inside the box
Lastly, inside the ProLon 5-Day Kit, there is a pamphlet with instructions and daily plans. What is a typical ProLon meal plan?

What Foods are Included in ProLon?
  • Bars
  • Herbal, non-caffeinated teas
  • ​L-Drinks (a specially formulated drink that maintains muscle)
  • Soup mixes
  • Crackers
  • Olives
  • Supplements

Below, you’ll see a meal card outlining what you’ll eat and drink during the fast.

Prolon review daily meal program calendar

ProLon Review: Who should try it?

For people who have battled their weight, metabolism, and digestion for years, the ProLon diet will be indispensable for you. Tracking your metabolic flexibility is a game-changer too.

Whether you have markers for chronic and unhealthy conditions or simply want to optimize your health on the inside, ProLon is, in our experience, the most scientifically proven and professionally designed plan on the market.

Sure, it will be helpful if you have some experience with intermittent fasting, however, previous fasting experience is not necessary.

So, who is the diet not for?

Who should not use ProLon?

People who are underweight, younger than 18, older than 70, pregnant, breastfeeding, allergic to ingredients in the food, or have a history of eating disorders should not do ProLon.

If you are on medications or have a health condition such as cancer, congestive heart failure, or diabetes, you need to consult your doctor. Here is ProLon’s statement on that.

“You should not stop taking any prescription medications, and should not stop using any over the counter (OTC) medications or supplements your healthcare provider has told you to use without discussing it with them first. For this reason, if you regularly take medications or supplements, please consult with your healthcare provider before starting ProLon.”

The Pros

While researching, testing, and writing up this ProLon review, these are the things we loved about the ProLon FMD diet.

  • It’s based on solid science with human trials done by reputable institutions like the Mayo Clinic.
  • We’ve confirmed that, in our experience, fast-mimicking does “trick” the body to stay in a fasted state!
  • We both lost comparable weight to the fasts we’ve done without food.
  • The boxes and plan are incredibly easy to follow.
  • The food is surprisingly tasty!
  • The fast didn’t seem to impact our sleep quality or irritability while improving focus.
  • ProLon can be started any day of the week, whereas a no-food fast has to be carefully planned out for Day 2 and 3 grumpiness.
  • No meal planning. Just add water.
  • It’s so simple. No thought required.

While the pros and cons list in our review of ProLon is heavily positive and compelling, there are still some things we disliked about ProLon.

The Cons

Onto the not-so-great things section of our ProLon review.

  • As of December 2023, ProLon is only available in the US and Canada.
  • Might cause hanger, although all we experienced was food jealousy.
  • Must love soup and olives.
  • You need to be careful with the food you eat after the fast. We took it slow and went medium on the carbs. It went perfectly.

Lastly, the smell of keto breath was a real con (at first we thought our new toothpaste was bad). However, the fact that it showed we were in ketosis from Day 3 onward was a pro.

Prolon 5-Day Fast FAQs and Takeaways

Before we started our ProLon, we had questions and I am sure you do too. Fortunately, once you get your ProLon 5-Day Program and open the box, it becomes incredibly easy to understand.

Additionally, the ProLon Facebook Page is a great resource, otherwise, feel free to ask us in the comments section of this article.

ProLon Fast Mimicking Diet Review FAQs

Do people lose weight with ProLon?

Yes, but that’s not what the diet is about. We already shared our weight loss data but on average, according to ProLon, people lose an average of 8.2 lbs. and 1.6 inches off their waist circumference.

Is the fast mimicking diet better than water fasting?

Based on our experience, it’s much better. We shared our comparative data in the results and experience sections. If you have an opinion here we’d love to hear from you in the comments.

For us, the FMD diet was far more manageable. Our hunger levels were lower, there was no insomnia, and the cleansing of our digestive system was more complete. It really felt like a normal week.

Does ProLon work long-term?

A lot of people are asking this question online and we think they’re missing the point. So, we’ll answer this question with some more questions.

Does all the weight you lose during the 5-Day Diet Program stay off? No, some of it is going to come back when you resume eating normally.

Can you follow the ProLon diet every day for the long term? No, you should not do the ProLon diet more than once per month.

What do you do after the ProLon fasting mimicking diet? Every time you follow the program, you are resetting and reprograming your body to crave healthier foods. After the 5-day diet, you should return to clean(er) eating.

Yes, ProLon does work long-term. Every time you follow the program, you’re strengthening your health and improving longevity.

What is the hardest day with ProLon?

Generally, days 2 and 3 are the hardest. In all the 3+ day fasts we’ve done, day 2 is almost always the hardest. That was the case for both of us during the ProLon FMD program, although it wasn’t that difficult.

Is the Prolon diet legit?

Considering ProLon’s numbers, we don’t know of a more legitimate diet program or supplement company.

  • 36M in research and development
  • 100+ global patents on their nutrition technology
  • 32 clinical trials
  • 18 prestigious university partners

That’s extremely impressive. As engineers, this speaks volumes about their commitment to quality and innovation.

Can you drink caffeine on ProLon?

Ideally, no. Why can’t you have coffee with ProLon? Here is their official response.

“Caffeine mildly stimulates the nutrient sensing pathway called the PKA pathway (as well as some other pathways) that ProLon down-regulates. For this reason, it is best to avoid caffeine during the diet, although you may have up to 140mg of caffeine each day, which is equivalent to approximately one 8-12 oz cup of black coffee, two cups of black or green caffeinated tea, OR 6 cups of decaffeinated coffee, all traditionally brewed.”

What is the L-Drink in the Prolon FMD?

We were very curious about the L drink when we started our 5-day fast.  It’s a glycerin drink that energizes you and protects your lean body mass (muscle) while keeping you in a fasted state. 

We recommend having your L-Drink with the hibiscus tea. It’s a treat!

Does ProLon put you in ketosis?

It put us in ketosis, yes. After following the program for five days, I have a hard time believing this wouldn’t be the case for everyone. 

What foods can you eat on the ProLon diet?

Stick to what’s provided. ProLon says that “​​additions are discouraged to minimize the risk of breaking the fast.” However, as an absolute last resort, ProLon allows the following additions.

  • Unsweetened and caffeine-free herbal teas
  • All types of unsweetened sparkling water
  • Up to 140 mg of caffeine per day (as mentioned, we drank coffee)
  • No more than 1 Tbsp. dried herbs or spices (we thought the soups were perfect as is)
  • Less than 1 Tbsp. of sea salt daily
  • Up to 2 slices of squeezed lemon per day
  • Two slices of sugar-free gum per day is allowed

If you’re struggling hardcore, we suggest reaching out in the comments for help or posting in the ProLon community facebook group for support.

Can you drink alcohol on Prolon?

Nice try. Of course not. Alcohol is not on the meal plan which you should not deviate from. 

Is ProLon a Keto Diet?

No, it’s vegan and the carbs are all from vegetables. 

Closing THoughts on the ProLon FMD Diet

Holy cow, this thing worked.

We’ve done no-food fasts before and ProLon was just as effective with none of the suffering. ProLon actually made our life easier for not having to plan 5 days worth of food!

But in all seriousness, we were impressed by the quality and tastiness of the product. We felt safe, taken care of, and loved that everything was based on decades of scientific research. Plus, the program comes with the founding scientist’s book for further motivation to continue a healthy diet afterward.

What we found most valuable with ProLon is that it allowed us to go into a longterm fast without needing a doctor’s supervision. Before, at our longest, we only fasted up to 3 days, but by doing so, skipped out on the benefits that only come with longterm fasting. This includes stem cell production, deep ketosis, and cellular autophagy.

To us, this is the biggest reason to try ProLon, as we all strive our best to live healthier, longer lives.

We hope that you found our ProLon review, experiences, graphs, and photos helpful.

If you’re ready to fast, please use our 10% 20% discount with code RYANANDALEX.

Good luck! Once your ProLon comes in the mail, feel free to reach out to us for support. For more helpful resources, such as the link between fasting and testosterone or the guide to breaking an intermittent fasting plateau, head over to our Fasting Page.

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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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