What are the proposed benefits of fasting (and perhaps, fasting mimicking)? How does one feel when they do FMD? I recently embarked on my first ever fasting mimicking diet (FMD) experience and I’d like to share some of my take-aways with you.

What are the benefits of the fasting-mimicking diet (FMD)?

A lot of the research on FMD thus-far has been in mice, not in humans. Now that ProLon exists researchers are better able to standardize the FMD and research it in humans. I think this will be an exciting area of study in the coming years!

  • In humans, ProLon FMD has been shown to (link)-

    • Decrease inflammatory markers IGF-1 and C-Reactive Protein (CRP),

    • Decrease body weight, waist circumference, abdominal fat (visceral fat), and blood pressure

    • Increase stem cell production

  • In Mice, FMD has been shown to-

    • Decreased intestinal inflammation in mice with IBD (Inflammatory Bowel Disease, Crohn’s and Ulcerative Colitis) (link).

    • FMD reduced autoimmunity and promoted tissue regeneration in the mouse model of Multiple Sclerosis (MS) (link).

    • FMD enhances cellular cleanup (autophagy) and regeneration, decreases the incidence of inflammatory diseases including cancer, improves cognitive abilities, and lengthens the lifespan and HEALTHspan of mice (link).

    • Potential reversal of diabetes type 1 and 2. Researchers noted that FMD promoted the growth of insulin-producing cells in the mouse pancreas, which reduced the symptoms of diabetes (link).

    • FMD may promote tumor-killing by host immune cells by enhancing T Cell-mediated tumor cytotoxicity (mouse model of breast cancer) (link).

  • More articles here: Link

My Experience doing ProLon: Day by day

  1. I was hungry most of the day on day one. Otherwise I felt no different than normal.

  2. Similar to day 1- I was hungry, but didn’t feel otherwise different.

  3. This was the turn-around point for me. I really wasn’t hungry at all until about 4:00 pm, and I noticed that I felt very mentally clear (not tired, not brain-foggy).

  4. Similar to day 3, I felt great on day 4. I didn’t get hungry until 4:00 felt good. I also noticed that I got out of bed a little easier (this is a chronic concern for me).

  5. The last day of ProLon went smoothly, too! I felt energetic and not foggy at all, and I didn’t get hungry until about dinner time. I felt like I could keep going if I didn’t enjoy the taste of real food so much 😉 I will admit I spent some of my day fantisizing about what I would eat for breakfast on day 6…

  6. This is the transition day after the ProLon FMD, and is not included in the kit. They recommend easing your way back into normal food and not going crazy on processed foods or animal protein. As I write this article (at 11:00 on day 6) I feel great (mental clarity and energy still great). I had overnight oats for breakfast this morning, which I enjoyed thoroughly.

Would I do it again? Yes and No.

Overall my experience doing ProLon was very positive. My main motivation was to learn about it from a first-hand perspective (so I can better coach my patients and tell them what to expect), but I think it was good for my health, too. There are folks who can’t do ProLon for allergen reasons, though (ex. soy, almonds), so I intend to do a DIY version in about a month so I can adequately coach people who decide to go that route. As an added bonus, I think I can get more variety in my diet if I control what I’m eating.

Questions and Answers:

  • Q: Does ProLon get you into ketosis?

  • A: I don’t believe so, no, although I didn’t measure my ketones to be sure. The breakfast bar has 9 grams of sugar in it (from honey), which would be too much to keep you in ketosis. The cocoa bar that you got with dinner a few nights had less sugar, but still enough to keep you out of ketosis, I think.

  • Q: Does the food taste good (on ProLon)?

  • A: Surprisingly, yes! It all tasted very good. I watered down the soup a little too much a time or two, but otherwise I found all of the food to be very enjoyable.

  • Q: Should I do ProLon if I have SIBO?

  • A: It depends. If you’re working with a practitioner to treat the SIBO and you are able to tolerate FODMAP foods, then yes, you should have no problem doing ProLon FMD. If you are unable to tolerate FODMAPs, however, you won’t care for ProLon. Most of the products contain Inulin, which is a type of prebiotic fiber that belongs to the FODMAP family.


  • Fasting is the practice of not eating anything caloric (containing calories) for a period of time.

  • Fasting Mimicking Diet (FMD) is a diet that is both low in calories and low in protein. The hope is that we can get the benefits from truly fasting while still eating some food.

  • ProLon is a commercial food product for doing the fasting mimicking diet. Each kit/box contains enough food for a five day FMD, which are all packaged in clearly labeled boxes 1-5. You also get instructions, a menu, and a water bottle (for the L-drink) in each ProLon kit.

  • Intermittent fasting (IF) is a pattern of eating where one goes for longer than normal stretches of time in a non-eating (“fasted”) state. For example, going from 6:00/dinner to 10:00 the following morning before you “break your fast” with calories. IF is all the rage these days, but in my opinion most folks are doing it wrong (more below).

  • Time-restricted eating (TRE) is practically the same as IF, but the name focuses is on when you DO eat as opposed to when you do NOT eat. Typically, time-restricted eating plans will allow one to eat calories within a few hour window of time, with the rest of the day being in a fasted state. I would say that all TRE practicers also do IF, but not all IF eaters necessarily do true TRE.

  • “Keto” or the Ketogenic diet is also very popular these days. Keto is a diet very high in fat, moderate to low in protein, and low in carbohydrates (including sugar). Note, true keto is not the same as Atkins, which is typically higher in protein (25%+ vs 10% or less).

  • Ketosis is when your body is making energy mainly from fat and is producing ketones. This is the claim-to-fame of the ketogenic diet (above).

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