Prolon FAQ

Prolon Diet FAQs (with official Prolon answers)

Deborah KayBy Deborah KayMay 31, 202110 Minutes

After four rounds of Prolon (myself) and a combined 60+ rounds (with friends), here is a compilation of frequently asked questions that I get, and the answers that I found in the official Prolon Facebook group. (I also wrote 16 Prolon Tips Before You Start the Diet)


What happens during the 5 days?

  • Day 1: Transforming to a Fasting State: Your body is transitioning to a fasting state and fat- burning mode, and begins preparation for cellular clean-up.
  • Day 2: Fat Burning & Ketogenesis: Fat-Burning ramps up, contributing to the initiation of ketogenesis (ketone production). By the end of this day (48 hours), ketosis may occur.
  • Day 3: Autophagy Clean Up State: Cellular clean-up (autophagy) begins. Fat-burning and ketone production/utilization continues and increases.
  • Day 4: Cellular Rejuvenation: Cellular cleaning/renewal & fat-burning continues. You’re in the final stretch.
  • Day 5: Renewal & Change: Fast completed, cellular renewal continues beyond Day 5.

(Source: Official Prolon FASTINATION Facebook Group)


How often should I do Prolon?

The official Prolon response is to follow the clinical trial once per month for three consecutive months.

After completing the 1st three cycles, you can do the program from time to time when you are looking for rejuvenation. Dr. Longo recommends a minimum of 25 days between cycles. (Source: Official Prolon FASTINATION Facebook Group)

In a separate interview with Dr Rhonda Patrick, Dr Longo says that an individual’s health status dictates how frequently they should practice a fasting-mimicking diet. For example, an athlete on a strict diet may prefer twice a year, whereas an obese person may choose monthly.

Some individuals favor this strategy for weight loss as it requires them to struggle for five days and then allows them to eat without restrictions for the remainder of the month. (Source: Found My Fitness – How frequently should you do the Fasting Mimicking Diet?)


I have a headache. What do I do?

This is quite common and I’ve had at least four friends complain of low grade headaches while doing Prolon. Usually it’s a sign of insufficient sodium or a caffeine headache.

The official Prolon response is to add some Himalayan salt to soup or water. If it is a caffeine headache, have a small amount of caffeine. Stay hydrated. If none of this helps, it’s OK to take your preferred headache medicine.

(Source: Official Prolon FASTINATION Facebook Group)


What can I drink?

  • Water (hot or cold)
  • Any herbal teas that are decaffeinated and unsweetened. You can choose the ProLon teas in your meal kit or any herbal tea of your choosing that fits the above criteria.
  • L-Drink on Day 2-5 which is included in your meal kit. This is a must to retain muscle mass so don’t skip.
  • Sparkling water without added calories or sweeteners.
  • You can add the juice of one lemon wedge.
  • If you absolutely can’t live without, we allow up to 90mg caffeine a day which is one cup of black coffee (8 fl oz) or two cups of decaf coffee or black/green tea (16 fl oz) per day.

(Source: Official Prolon FASTINATION Facebook Group)


Is stevia allowed while using Prolon?

Recent studies have demonstrated that the use of stevia during fasting does not significantly alter insulin or blood sugar levels. [1],[2],[3]. To enhance adherence to ProLon, ReSet, and Fast Bar, we now permit the addition of stevia (natural sweetener) to coffee or tea when using ProLon products. We recommend that consumers limit Stevia use daily during ProLon, ReSet or Fast Bar use to one to two of the recommended servings for the brand of stevia being used.



What is in the L Drink?

The L-Drink is primarily glycerin. When you have plenty of sugar in your bloodstream, you don’t use glycerin for energy. In fact, your body excretes it out. But when you need more sugar, especially during your fast, your body releases glucagon which activates the production of sugar from many different sources:

1. Glycogen in the muscles and liver
2. Amino acids which are primarily found in the muscles
3. Glycerol

The first two sources can potentially cause you to lose some muscle mass, which typically happens on a water-only fast.

On ProLon, we give you support through the L-Drink, which helps protect your muscles while fasting. The L-Drink must be discarded after the fast. When consuming the L-Drink, you can enjoy it hot or cold with teas or with water.

(Source: Official Prolon FASTINATION Facebook Group)


Can I keep and re-use the remaining L Drink?

The L-Drink is intended to be consumed during the diet as a 1-time use only. We did not prepare it to be stored post-program, so it is best to not save this. Additionally, there are no established benefits to using the L-drink outside of the diet so it has no purpose if you are not in a fasted state. Please discard after one use.

However the L Drink bottles make pretty nifty travel shampoo bottles so you can recycle them that way! (Check out this pic!)

(Source: Official Prolon FASTINATION Facebook Group)


I’m dying of hunger, can I snack on something?

You should add food to the program only as a last resort if you are so incredibly hungry that you feel like you are going to break the fast. In such an instance, you may have a slice or two of apple, 1 stalk of celery, or 1 small Persian (“baby”) cucumber of 5-6 inches in length per day.

You can add:

  • Up to 1 tablespoon of dried herbs or spices per day to your soups or other foods in the diet to enhance the flavor (preferably unprocessed, e.g., red pepper flakes)
  • Up to 1 teaspoon of sea salt (as long as there are no health contraindications)
  • Up to 2 slices of lemon per day (squeezed, not eaten), whether you use it in your soups, herbal teas, or water.
  • Up to 2 pieces of sugar-free gum per day while on ProLon.

(Source: Official Prolon FASTINATION Facebook Group)


I’m bloating and farting a lot on ProLon. Why?

There are a couple of reasons why:
1. We do include inulin in the diet, which is a popular plant-based fiber, which some people can be a little more sensitive to, resulting in cramping and bloating.
2. You’re doing something new to the body for five days and when you do that you can get changes in your microbiome, which can create extra gas.
3. There has been some evidence that when you are in a fasted state, your gut biodiversity goes up, which might be a good even though it can be uncomfortable.

*If you are experiencing severe pain, please privately message us or consider discontinuing the diet and contacting your healthcare provider*

(Source: Official Prolon FASTINATION Facebook Group)

Some people in the Facebook group suggest soaking the soups in water and say it helps prevent the bloating.


The information here is for informational purposes only. This website does not provide medical, professional, or licensed advice and is not a substitute for consultation with a health care professional. The use of any information on this website is solely at your own risk.


Read next: 16 Prolon Tips Before You Start the Diet

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