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ProLon Reviews: Is this the best way to fast in 2023?

ProLon promises to deliver anti-aging and weight loss benefits from 5-day-long fasts that still let you eat. Sounds too good to be true? We dug into the research to find out.

Last Updated: Jan 2, 2023
ProLon Reviews

Fasting can provide many benefits, even without going to extreme lengths. Weight loss is one of the most commonly documented benefits, but other fasters report increased focus and energy levels, lower incidence of illness, and more. On the clinical side, studies seem to back up these anecdotal reports.

But there seem to be even more ways to fast than there are potential benefits of fasting. Specific methods will be easier to follow for some people than others. For instance, people who can’t keep track of time might not be ideal candidates for the 16:8 method. They’d likely do better with OMAD fasting or alternate-day fasting.

As we give you our thorough analysis of ProLon, we’re going to take a look at these different fasting methods to illustrate how ProLon seeks to challenge the typical approach to fasting without sacrificing its benefits. Find out if it’s right for you.

Review Summary


  • Provides the benefits of fasting with less hunger
  • Foods are tasty
  • A great way to kickstart healthy eating
  • The plan is clearly laid out
  • Everything is vegan and gluten-free
  • Free 20 min health coach consultation with all purchases
  • Get a free box of Fast Bars (25 ct) with your first order


  • A little on the pricey side
  • Results aren’t as noticeable if you’re already healthy
  • No fresh foods for five days

Bottom line

We recommend ProLon for its fasting-mimicking diet that sounds unrealistic at first but has enough clinical evidence in support of it that you should take it seriously. Study participants saw decreased blood pressure, body fat, and cholesterol alongside increased concentration and clarity. For anyone already living a healthy lifestyle, ProLon might provide fewer benefits. You’ll likely miss fresh fruits and vegetables on what is a completely prepackaged diet. Fortunately, it’s a short enough program that you can quickly get back to healthy quantities of fresh foods after reaping the benefits of fasting with less hunger.

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A clever and effective “fast-mimicking” experience provides you with meals that come in 5 grab-and-go boxes – one for each day.

ProLon’s approach is backed by 20 years and $34 million in research & development. It’s a convenient way to reach your weight loss goals and rejuvinate your body. Pick between 3 customized plans to start.

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Why you should trust us

Over the past two decades, Innerbody Research has helped tens of millions of readers make more informed decisions involving staying healthy and living healthier lifestyles.

We extensively test each health product and service we review. We try our best to give you, our readers, unbiased exploration of at-home health services, free of marketing jargon or gimmicks. We base our evaluations on adherence to quality, the latest medical evidence and health standards, and a simple question: would we buy the product or service ourselves if it weren’t part of our job, and would we recommend it to family and friends?

Additionally, like all health-related content on this website, this review of ProLon was thoroughly vetted by one or more members of our Medical Review Board for accuracy.

What is ProLon?

ProLon is a fasting system that isn’t even technically fasting. The program lasts five days, and you get to eat every day. The key is that your body doesn’t recognize the foods you get from ProLon in the same way it recognizes your everyday diet. That allows your body to enter a fasted state without wholly denying yourself calories.

Clinicians don’t refer to this clever dietary sleight of hand as fasting per se. They call it a fasting-mimicking diet because it mimics the experience your body would have during a fast, providing you all the benefits with less hunger.

What kind of food do you eat on ProLon?

If you want to get the most out of the ProLon experience, you’ll want to follow the diet plan strictly. Interestingly, the diet is almost identical regardless of weight, height, or age. Based on these factors, the only thing that changes is the quantity of a specialized glycerin drink that your body uses for extra energy. The more you weigh, the more powder you pour when making the drink.

Here’s a quick breakdown of the foods you’ll eat from ProLon throughout the five days.


Soups are going to be your primary source of food throughout the day. You’ll have a soup for lunch and another for dinner. There are nine soup types in the company’s arsenal, but you have to choose between two sets of five, so they may still get repetitive. Each soup is dry and comes pre-measured in a packet. You simply add hot water.

Soup flavors in the Original lineup include:

  • Vegetable
  • Tomato
  • Mushroom
  • Vegetable quinoa
  • Minestrone

New flavors of soup include:

  • White bean and spinach
  • Black bean
  • Butternut squash
  • Butternut squash and quinoa
  • Tomato


You’ll get a few small snacks throughout the day. ProLon includes their Fast Bars in this category, as well. They’re your primary source of calories at breakfast. In all, your snack options look like this:

  • Nut-based L-bar
  • Cocoa-based L-bar
  • Kale crackers
  • Almond and kale crackers
  • Olives with herbs or sea salt


ProLon comes with some particular drinks you will want to consume as suggested. The most important of these is the L-drink, which contains glycerin. You measure this drink out based on your body weight, and it can give you extra energy throughout the day – energy that you might miss when your calories are low.

You’re free to enjoy whichever flavor of L-drink or tea you want when the plan calls for it.

The drinks include:

  • Tropical berry-flavored L-drink
  • Orange-flavored L-drink
  • Hibiscus herbal tea
  • Spearmint herbal tea
  • Spearmint lemon herbal tea


ProLon comes with two dietary supplements. One is a powder, and the other is a capsule. The powder helps stave off vitamin and mineral deficiencies you would otherwise experience due to the diet’s restrictive nature. The capsule provides you with a healthy dose of Omega 3s.

  • NR-1 vegetable powder with vitamin and mineral supplement
  • Algal oil capsules

If you want to shake things up, you can choose to eat your daily allotted foods in any order you please. However, you can’t trade foods from one day to another. We recommend making those permitted daily adjustments if it means the difference between staying on the plan and cheating. But the best possible course of action is to follow their plan to the letter.

All of ProLon’s products are vegan and gluten-free. Everything but the algal oil supplement is soy-free, as the capsule contains soy lecithin.

The ProLon meal plan

ProLon’s 5-day meal plan is easy to follow. We break it down for you here, so you can see what your 5-day experience will be like.

  Day One Day Two Day Three Day Four Day Five
Breakfast Nut L-bar, Tea, 2x Algal oil Nut L-bar, Tea Nut L-bar, Tea Nut L-bar, Tea Nut L-bar, Tea, 1x Algal oil
Lunch Tomato soup, 2x NR-1, Kale crackers, Olives Mushroom soup, 1x NR-1, Olives Tomato Soup, 1X NR-1, Kale crackers Veg soup, 1x NR-1, Olives Tomato Soup, 1X NR-1, Kale crackers
Snack Tea, Nut L-bar Tea, Olives Tea Tea, Olives Tea
Dinner Minestrone, Choc L-bar Minestrone & quinoa soup, Choc L-bar Minestrone Minestrone & quinoa soup, Choc L-bar Minestrone

This chart illustrates the plan with the original soup flavors. The new flavor plan is identical but for the substituted soups.

What about coffee?

Coffee is near and dear to many of us, and you don’t have to give it up on ProLon. However, you do have to take it black and limit yourself to 1-2 servings per day. And, for the record, a serving isn’t the biggest mug you can find; a serving is eight ounces.

ProLon pricing

Compared to other at-home diet plans, ProLon is undoubtedly expensive. But those other plans are typically long-term commitments. It’s better to think of ProLon as a way to jumpstart a diet that you’re about to begin or to revive a diet if you’ve plateaued. That’s why we prefer the subscription system. It offers the best price, and you can choose five days out of each month to perform the program.

Here’s a look at ProLon’s costs and how bundling or subscribing can save you money:

  • Single box – $187
  • Single box subscription – $179/box
  • Double box (great for couples) – $340 ($170/box)

ProLon also offers fasting bars. You can theoretically consume these bars without breaking that fast. Clinical studies have included them in trials of the ProLon system, but they have not been tested on their own at this point. Based on our knowledge of fasting science and biology, it’s hard to conclude that these bars do what they promise without further clinical testing.

Bar prices decline with larger purchases, and you can save a little more by subscribing. Here’s a look at the lowest possible costs for each flavor:

  • Nuts and Honey – $2.28/bar
  • Nuts and Dark Cocoa – $2.28/bar
  • Nuts and Cacao Chips – $2.28/bar
  • Blueberry Acai – $2.85/bar
  • Lemon Berry – $2.85/bar
  • Variety Pack – $2.66/bar

One-day reset

ProLon’s one-day reset is a truncated version of their 5-day plan designed as a break from bad habits and an opportunity to get off an unhealthy course. It’s the kind of thing you might reach for after a holiday weekend or an indulgent vacation. In our view, it serves as much as a psychological reset as it does a physical one.

The one-day reset meal plan is very similar in content and caloric intake to the first day of ProLon’s 5-day plan. Here’s a look:

  • Breakfast: Fast bar, herbal teal, algal oil
  • Lunch: Tomato soup, almond and kale crackers, two NR-1 packets
  • Snack: Olives, herbal tea
  • Dinner: Butternut squash soup, intermittent fasting bar

The one-day reset costs $39.99, but you can bundle or subscribe to bring that cost down to $35/box.

Payment and shipping

ProLon accepts all major credit cards, and they offer financing through Shop Pay. Shipping on all orders is free, but it can take up to 10 days for your package to arrive.

How is ProLon different from regular fasting?

Regular fasting involves denying yourself any calories for extended periods. It relies on your body’s ability to break down its own tissue for sustenance. Theoretically, this can help you with weight loss. But some forms of fasting aren’t all about shedding fat; getting slim is merely a byproduct of improving health. Let’s take a look at some of the most popular forms of fasting so we can see how ProLon is different.

Intermittent fasting

Intermittent fasting most often refers to a scheduled daily fast that lasts for a set time. That gives you a specific window each day during which you will consume your day’s worth of calories and nutrients. There is evidence that working out toward the end of a short fast can increase fat burning. This is a point of divergence with ProLon, as their program advises against strenuous exercise over the five days.


A fasting regimen with a 12-hour eating period and a 12-hour fasting period. This is an excellent place for people to start if they’re new to IF.


This regimen has an 8-hour eating period and a 16-hour fasting period. It’s a little more advanced but surprisingly easy if you adjust your schedule correctly.


This regimen has a four-hour eating period and a 20-hour fasting period. People on this plan may not do it daily, but rather as a push day in the middle of a 16:8 program. It coincides nicely with one meal a day fasting.

One meal a day

One meal a day, or OMAD fasting, is just what it sounds like. You have one meal in a given day to consume all the calories and nutrients your body needs. This extreme form of fasting requires extensive nutritional knowledge and the time and skill to create completely nourishing meals for yourself. A slightly less intense two meals a day (TMAD) diet is a more sustainable alternative.

5:2 fasting

With 5:2 fasting, you eat like you usually would for five days out of every week and completely abstain from food for the other two days. It’s important to note that those two fasting days are not back-to-back. You wouldn’t fast Tuesday and Wednesday and eat the rest of the week. Instead, you might fast Monday and Thursday only, for example.

Alternate day fasting

Alternate day fasting has you eating every other day. This methodology doesn’t fold well into a 7-day week, so you can’t plan to eat on Saturdays like you can with the 5:2 system. Alternate day fasting can be tough to maintain, and we wouldn’t recommend anyone start there.

How ProLon is different

For any of the fasting methods we mention above to work, you have to wholly abstain from food for the duration of the fasting period. There are minor exceptions, like the calories technically present in coffee. But beyond caffeine and maybe natural flavors found in things like flavored, unsweetened seltzer, you only take in water.

The big difference between ProLon and these types of fasting is also its most important selling point: you still get to eat.

Studies show that the same health indicators that change during a traditional fast — blood pressure, insulin-like growth factor, cholesterol, and C-reactive protein levels, among others — changed in similar numbers during a ProLon meal plan.

How can you eat and still be on a fast?

Technically, you can’t be on a fast if you’re eating, but you still can trick your body into providing you with the benefits of fasting. That’s what ProLon’s meal plan is all about. You might consume a few hundred calories in a sitting. Still, the micro-and macronutrient balance that Prolon’s foods provide helps prevent these foods from spiking your blood sugar or even signaling your body that it’s eating food. This is the essence of the fasting-mimicking diet.

Insider Tip: Everyone’s body and experience will be a little different, but most people find the middle of the fast to be the most difficult. Plan for something that will occupy your mind and distract you from any hunger or weakness you might feel. And hydrate like crazy.

Is ProLon safe?

ProLon is generally safe, but it’s a good idea to talk with a physician or nutritionist before beginning any new regimen. Fortunately, ProLon works that consultation into their pricing model, so you get a one-on-one session with a nutrition coach before you start. Have specific questions about your health and safety at the ready, though. If they can’t answer them for any reason, talk to a doctor before starting the program.

There are still plenty of reasons you may ultimately decide not to use ProLan (or may not be a suitable candidate for it). The company explicitly states that the following people should not use their program:

  • You have a fever, cough, diarrhea, signs of an active infection, or are at risk for recurrent infection;
  • You are underweight, breastfeeding, or pregnant;
  • You have dietary restrictions;
  • You have a known, suspected, or diagnosed eating disorder; or
  • You are under 18 or over 70, unless you’re under the supervision of a healthcare provider.

Is ProLon a good value?

If you were to judge ProLon’s value strictly on the quantity and freshness of the food it provides, you’d assume it wasn’t worth it. There are plenty of healthy meal plan companies out there that deliver higher-quality ingredients for a lower monthly cost. But you’re not supposed to stay on ProLon for weeks or months, as is the case with those other plans.

ProLon is at its best when you use it as a short run before weight training or a palate-cleansing piece of pickled ginger between sushi rolls. It sets you up for what’s to come next — ideally, a healthy lifestyle. When you use ProLon like this, it has tremendous value.

Is ProLon right for you?

Whether or not ProLon is right for you will depend on a few factors. Individuals already in great shape will likely notice less dramatic results than those with higher blood pressure, more body fat to lose, etc. There are essential anti-aging and immunity benefits to fasting, though, so you shouldn’t confine yourself to cosmetic considerations.

Let’s take a look at some possible perspectives going into a ProLon diet:

You've never fasted before

The prospect of fasting can be intimidating, especially for newcomers. ProLon is an excellent place to start if you’ve never fasted before because it allows you to see how you feel fasted without as much crash-and-burn risk. The program starts you off slowly, with a decrease in calories as it goes on. If you’re successful, you might just try a traditional fast next time around.

You've fasted before and hated it

If you have some fasting experience and you’ve either crashed in the middle or gotten through it only to gorge yourself beyond the benefits the fast provided, then ProLon is probably a good idea. The ability to enjoy some tasty foods throughout the day is critical for many people’s psychological and emotional well-being, and this doesn’t force you to deny yourself that.

You've fasted before and loved it

ProLon is a 50-50 prospect if you like to fast. It can give you a new perspective on fasting that expands your horizons and gives you another tool in your wellness arsenal. But if you find it’s easier to stay strict during a fast when you don’t even think about food, then having food as part of a fasting-mimicking system might be too much of a temptation for you.

You have a medical condition that prevented you from fasting before

ProLon is adamant that you don’t put yourself in danger with the goal of weight loss. Ideally, weight loss is a byproduct of better health, not the goal. And any medical condition that has prevented you from experimenting with fasting might also be an issue on ProLon’s diet. This is a situation where it’s best to talk to your doctor first.

Getting started with ProLon

ProLon makes ordering and performing their diet extremely straightforward. Their website is intuitive, and their packaging tells you everything you need to know. Each day’s food comes packed in its own little box, so you don’t have to worry about mixing things up. Here’s what the process looks like step-by-step:

  1. Head over to the ProLon website and order a fasting kit. You can choose from two selections of soups, but everything else about the packages is the same.

  2. Plan ahead. You’ll want to have a full seven days during which you can devote yourself to the system. For at least one day before your program starts, you should be mindful of your portions and hydrate thoroughly. And the day after your program ends, ProLon suggests slowly returning to a regular, healthy eating pattern.

  3. Follow the plan carefully. You don’t want to miss meals or supplements. Clinical trials relied on ProLon’s specific protocol. Augmentations, substitutions, or subtractions from the plan will likely fail.

  4. Come off the program and into better eating habits. When you finish your five days, you don’t want to go straight to the donut shop. ProLon can help jumpstart a period of healthy eating if you let it.

How we evaluate home health products and services

At Innerbody Research, we customize our evaluation criteria depending on the type and nature of the health-related service or product. For health products and services, we have five areas that we use for our evaluations, including:

Quality: How well does the company deliver its core service(s) to the customer? For testing services, does the company adhere to the latest and most advanced testing technologies and achieve a very high degree of accuracy? For non-testing telemedical or teletherapy services, is the quality of the service high enough that we would recommend it to loved ones without hesitation? If not, why not? For health products, does the product or device meet a high level of safety? Is it manufactured with high quality standards? Has it – or have its ingredients – been subjected to studies that confirm effectiveness?

User-friendly: How intuitive and convenient is the service or product? Does the device, program, app, or website achieve a good degree of user-friendliness for its customers?

Value: Are you getting your money’s worth? Are there any hidden costs or charges? Does the company offer discounts?

Privacy: If health data is stored, will your data be stored securely? Are payments secure? Does a company market your information?

Customer support: Particularly in situations where ‘one size fits all’ doesn’t make sense, how well does the company help to make the service or product ideal for you or address your individual needs?

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