How Prolon Works: The Science-Backed Path to Longevity (and so much more!)

Maybe you’ve heard some buzz around Prolon, read the studies, or know someone who swears by it—but you may be looking for the full story on exactly what it is and how it works. The answer, in short, lies in science: Prolon uses precisely formulated foods that bypass the body’s nutrient-sensing pathways, allowing it to mimic a fasting state. This activates natural biological processes that trigger deep cellular renewal, unlocking a wide range of long-term, proven benefits to help you look and feel your best for longer.

Here’s everything you need to know about how Prolon works from a biological standpoint, how it works with your lifestyle, the science behind it, and why it can be an accessible, effective way to meet your health goals. 

What is the Fasting Mimicking Diet?

Prolon is the first and only nutrition program patented to support longevity through cellular rejuvenation. Backed by over 25 years of research and more than 40 clinical studies, this isn’t a detox or a diet; it’s a structured, science-backed way to help your body repair, reset, and thrive from the inside out to support a longer, healthier life. 

The origins of the program start with Dr. Valter Longo, the Director of the USC Longevity Institute and leading expert in aging and longevity. In studying the habits and diets of populations that have the highest number of centenarians (those who live healthily into their hundreds), he discovered a common thread: fasting plays a critical role in promoting both lifespan and healthspan, the number of healthy and vibrant years in one’s life.

But while fasting can trigger powerful biological processes like cellular cleanup and regeneration, traditional prolonged fasts, such as water-only fasts, are often difficult to adhere to and can come with health risks. That led Dr. Longo to develop a new approach—a way to nourish the body while keeping it in a fasting state. The result was the Fasting Mimicking Diet (FMD), a scientifically designed, five-day nutritional program that avoids activating the body’s nutrient-sensing pathways, allowing fasting-related processes like ketosis and autophagy to continue, even while eating.

Why do Prolon? 

People turn to Prolon for many reasons. Some are looking for a quick metabolism reset, to jumpstart weight loss, improve energy, or boost mental clarity. Others are focused on long-term goals like metabolic support and longevity. What they all have in common is a desire for a safe, science-backed way to experience the benefits of fasting without complete food deprivation or putting life on hold. That’s what makes Prolon a trusted choice for supporting both immediate results and lasting health. Here’s why the Prolon FMD is a go-to solution for so many people: 

1. Clinically proven benefits

Even one five-day cycle of Prolon has been clinically shown to:*

• Reduce visceral fat while protecting lean muscle, with many users reporting a five-pound weight loss with one cycle - and sustained results even after return to normal eating
  
  

• Activate autophagy, the body’s natural cellular cleanup process
  
  

• Support a post-fast boost in energy, mental clarity, and skin radiance
  
  

• Help reset metabolism and support metabolic health
  
  

Three consecutive monthly cycles have been clinically shown to:*

• Reduce biological age by 2.5 years
  
  

• Support healthy cardiometabolic markers and immune health
  
  

• Protect muscle mass and bone density
  
  

• Improve skin hydration, smooth fine lines, and even skin tone
  
  
  

2. Rooted in science and research

Trust is one of the biggest reasons people choose Prolon—because it’s rooted in science and clinically tested for real results. Here’s what’s behind every Prolon 5-Day Program, and every product we make:

• 25+ years of research
  
  

• 40+ peer-reviewed clinical trials
  
  

• $48M in research funding from institutions like the NIH
  
  

• Studies conducted at leading universities including, USC, Stanford, Mayo Clinic, and University of Miami, among 14 others globally
  
  

• Trusted by more than 15,000 healthcare professionals and used by over 1 million people worldwide
  
  

3. Simplicity and convenience

While the above all sounds compelling, you might still be wondering: Can I actually do this without disrupting my life? The answer for most people is a resounding yes. Prolon is structured, manageable, and easier to stick with than water-only fasts or restrictive diets. Here’s how Prolon fits into real life:

• No planning, cooking, or counting: All meals, drinks, and supplements are included in the box, along with an easy-to-follow meal card.
  
  

• Minimal disruption: Because you still receive nourishment and are eating some food, most people have the energy to continue working and handling daily responsibilities, with a few minor adjustments (like avoiding intense workouts or dining out socially).
  
  

• Minimal time commitment: Unlike long-term extreme diets that drastically alter your eating patterns, or weight-loss drugs like GLP-1s that you may need to be on permanently, Prolon is a periodic program designed to be done just a few times a year. Start with three monthly cycles (15 total days over 90), then maintain your results with just three to four cycles per year (only 15 or 20 days over 365) for optimal ongoing benefit. Clinical studies show that more than 60% of the benefits achieved after the initial cycles are still maintained three months later, even after you’ve returned to normal eating.

What’s in the Prolon box?

Each Prolon 5-Day kit contains everything you need to complete your fast safely, effectively, and without guesswork. Inside, you’ll find five individual boxes, one for each day, with all meals, drinks, and supplements for that day, plus a meal card for guidance. Each food item, and each day’s lineup of meals, is precisely designed to keep your body in a fasting state while still providing nourishment to support energy, protect lean muscle, and fuel cellular renewal. Carbs and plant protein are carefully portioned to fuel your body, while healthy fats from olives, nuts, and seeds support satiety and cellular function.

Daily boxes include:

• Nourishing, plant-based soups. Flavors depend on the Prolon varietal you choose and may include Minestrone, Vegetable, Carrot Ginger, Lentil Curry, or ready-to-eat organic Artichoke & Yellow Tomato
  
  

• Fasting-supportive L-Bars (including our fan-favorite Choco Crisp) made with whole-food ingredients like macadamia nuts, cocoa, and prebiotic fiber carefully selected to nourish the body
  
  

• Savory snacks (kale crackers and olives) and herbal teas
  
  

• The L-Drink, a proprietary glycerol-based beverage that supports hydration and muscle protection
  
  

• Scientifically-formulated micronutrient supplements, including omega-3’s
  
  

It’s important to remember that you’ll eat and drink only what’s in each day’s box. You can change the order of consumption within a day, but do not swap items between days—each is specifically calibrated to support a different phase of the fasting and renewal process.

How Prolon works - the biological process

While typical diets focus on short-term weight loss or calorie restriction, Prolon works on a much deeper level by tapping into your body’s own biology to promote cellular repair, renewal, and long-term health.

It all starts with how your body responds to food, or the absence of it. Prolon works by staying below the threshold of the body’s nutrient-sensing pathways, which regulate key functions like growth, metabolism, and cellular repair. These include mTOR, IGF-1, and PKA, pathways that are activated when the body detects food intake and, in turn, shut down the beneficial fasting processes like cellular cleanup and regeneration.

Each of these pathways responds to different nutrient signals:

• PKA is primarily triggered by sugar and carbohydrates (and to some extent, caffeine)
  
  

• IGF-1 is largely activated by protein (especially animal protein)
  
  

• mTOR responds to both IGF-1 and amino acids

Together, these pathways determine whether the body is in a growth mode or a stress-resistant, regenerative fasting state. Each meal in Prolon’s 5-Day FMD is precisely calibrated and uniquely formulated to stay below the thresholds that activate these pathways. That means your body continues to believe it’s fasting, even while you’re being nourished with real, plant-based food. When the body hits around 72 hours of fasting, it enters a powerful state of renewal known as autophagy, where it begins clearing out damaged cells and making room for newer, healthier ones. It’s this process that drives the most profound, deep cellular rejuvenation benefits you can receive from the FMD. 

How Prolon works - day by day

Over the five days, Prolon helps shift the body’s metabolism, reduce visceral fat, protect lean muscle, and activate biological processes that are associated with healthspan.

Day 1: Transition
Glucose and insulin levels begin to drop as your body prepares to shift from glucose-burning to fat-burning mode.

Day 2: Ketosis begins
Your body starts using fat for fuel; Prolon’s formulation is unique in that it helps preserve lean muscle while supporting this metabolic switch.

Day 3: Autophagy activates
The cellular cleanup process kicks in. Damaged cells begin to break down and are removed or recycled.

Day 4: Deep rejuvenation
Autophagy continues, and fat-burning peaks. Your body prioritizes repair and renewal over growth and storage.

Day 5: Cellular reprogramming
With damaged cells cleared, the body begins producing newer, more resilient cells, essentially “reprogramming” them for more youthful function. This lays the foundation for continued benefits even after the fast ends.

What happens after the five days?

Although the fast ends on Day 5, cellular renewal can continue into Day 7, even after you start eating again. Day 6 is a gentle refeeding period that helps ease your body back into normal eating while reinforcing healthy habits, and by Day 7, most people are ready to resume their regular diet.

So what’s next? You’ve completed your fast, you’re feeling (and looking!) better—and you want to maintain those benefits. While prolonged fasts like the FMD are designed to be done only periodically, the good news is that one cycle is just the beginning. A single 5-Day Prolon round delivers meaningful benefits, but an initial phase of three monthly cycles followed by just three to four cycles per year can help amplify results and sustain long-term health and longevity.

But what do you do in-between cycles? That’s where the Longevity Lifestyle comes in. Inspired by the eating habits and routines of people in longevity sites - which have the highest populations of individuals living healthily into their 100s - incorporating these practices into your life can help you optimize, and even extend, the benefits of your 5-Day.

• Follow Longevity Diet principles -  A plant-forward, nutrient-dense way of eating with occasional - but sparing - fish and meat consumption
  
  

• Practice Circadian Eating Patterns -  Consume meals within a 12-hour daytime window that follow the natural circadian rhythms of sun up to sun down, and include breakfast
  
  

• Utilize The Longevity Nutrition Kit - A convenient, month-long plan designed to support healthy aging and keep you on track between Prolon cycles, with science-backed nutrition and easy to follow guidance
  
  

• Try 5:2 Fasting –  A powerful, proven way to support weight, metabolism, and longevity. Our  5:2 Fasting Program makes it easy, with two weekly structured 1-Day Reset kits to keep your body nourished while in a fat-burning state.

Common questions (and misconceptions)

It’s natural to have questions or hesitations before trying something new, especially when it comes to your health—and, particularly, fasting. Below, we’ve addressed some of the most common misconceptions and questions about Prolon. If you still have further questions, please reach out to our team.

“It’s just a box of processed food.”
While the meals are pre-packaged for convenience, every food item in the Prolon kit is made from high-quality, plant-based ingredients and designed to support clinical outcomes, not shelf life. In addition, all of our teas and Next Generation soups are 100% organic. 

“I’ll be starving!”
Most people are surprised by how satisfied they feel during Prolon. The program includes healthy fats, fiber-rich foods, nourishing soups, and energy-supporting drinks to help keep you going. Herbal teas also support hydration, which can naturally enhance feelings of fullness.

“Won’t I lose muscle?”
Unlike water-only fasts, many traditional diets, and GLP-1s, Prolon includes key components,  like the L-Drink and a precise amount of glucose from complex carbohydrates, to help protect lean body mass while targeting visceral fat loss.

“I won’t have energy to work out or think clearly.”
Prolon provides targeted nutrition designed to fuel your body while keeping it in a fasting state. Many people report steady energy, improved focus, and even enhanced mental clarity, especially as the days progress. While intense workouts aren't recommended during the 5-Day FMD, light movement like gentle walking or stretching is encouraged.

“I have a medical condition—can I still do it?”
Prolon is intended for generally healthy adults. However, If you’re under 18 or over 70, have a medical condition, take prescription medications, or are pregnant, breastfeeding, underweight, or managing an active infection, consult your healthcare provider first. Those with eating disorders or relevant food allergies should also avoid the program.  For those with metabolic concerns like obesity, prediabetes, or type 2 diabetes, our medical division, L-Nutra Health, offers personalized lifestyle medicine programs clinically shown to help reverse these conditions. 

“It’s too expensive.”
Weekly, the average adult spends about $152 on groceries, plus $48 dining out. When you consider that Prolon replaces five full days of meals and supplements, it is essentially cost neutral. Plus, you’re making a long-term investment in your health, which can actually cut costs in the long run.

Ready to begin?

Prolon isn’t just a fasting program; it’s a breakthrough in longevity science. Whether you're looking to reset your metabolism, support healthy aging, or start the journey toward a longer, healthier life, Prolon’s 5-Day FMD offers a proven path forward—and we’re here with you, every step of the way. Let’s get started!

*Sources and Clinical Trials:

https://www.mdpi.com/2077-0383/12/5/1710
https://www.nature.com/articles/s41467-024-45260-9
https://www.nature.com/articles/s44324-023-00002-1
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6816332/
https://pubmed.ncbi.nlm.nih.gov/35034194/
https://pubmed.ncbi.nlm.nih.gov/36902498/