Fasting Mimicking Diet Overview

One aspect of nutrition that I’m drawn to is the concept of cycling between two different strategies to yield better results than following just one strategy. This post is about benefits to cycling protein.

High Protein or Low Protein?

Although I have for years been skeptical of higher protein diets being necessary for building muscle, I have come around to seeing how much they can help with fat loss. Protein crushes appetite and preserves muscle loss – especially as one gets very lean. I covered the topic of P-ratio in the post High Volume or High Protein Foods For Fat Loss.

But I think there can also be a downside to using high protein all the time. In the post More Thoughts on High Volume or High Protein For Fat Loss, I covered a discussion Robb Wolf had with Joe Rogan on how very low protein diets accomplished via fasting resulted in extreme fat loss without the extra skin folds you normally see on high weight loss diets.

There is a healthy discussion in the comments, but I walked away thinking that if I were to choose between a higher or lower protein path for fat loss, it would depend upon where I was. The heavier I was, the more fasting (low protein) I’d use and then as I got leaner, I’d up the protein to preserve muscle. The great compromise.

Why Not Both?

Why not chose both strategies if it can yield better results than either one separately? Cycle protein levels to get the benefits of both approaches. That was my takeaway when I started researching the Fasting Mimicking Diet.

The Fasting Mimicking Diet was created by Dr. Valter Longo and was discussed on the podcast Found My Fitness. You can watch the interview on YouTube.

Valter Longo, Ph.D. on Fasting-Mimicking Diet & Fasting for Longevity, Cancer & Multiple Sclerosis

The show was very interesting to me. I listened to it twice and took some notes.

Overview of the Fasting Mimicking Diet

The Fasting Mimicking Diet is a diet that cycles between extremely low protein levels and normal protein levels. In the cycle, there are 5 consecutive days of reduced calories and low protein. The remainder of the cycle is normal calories and normal protein. A typical cycle might be monthly for someone with health issues or specific health goals, but your cycle could be quarterly I suppose.

  • Day 1: 1,090 calories (10% protein, 56% fat, 34% carbs)
  • Days 2-5: 725 calories (9% protein, 44% fat, 47% carbs)
  • Other Days: Normal calories and normal protein levels

The 5-day cycle mimics fasting and the benefits it provides but does it in a way that is easier to do for most people. By depriving your body of protein for 5 days the body responds with powerful repair mechanisms that address inflammation. And as they state in the interview, inflammation is predictive of aging.

Back in 2015, I did a post that referenced the 2011 online book Protein Cycling Diet by Dr. Ron Mignery. That book lists many health benefits one can get from very low protein levels and advises a 5% protein or less diet on dieting days. It is really hard to find foods with that little protein. The FMD solves for this by reducing calories, so the net protein is likely similar.

Ramping Up Stem Cell Production

During the 5 days of low-protein, the body increases its production of stem cells. One chart showed circulating stem cells counts triple from 0.3% to 0.95%. As someone that is interested in not only the health benefits discussed in the interview and those mentioned in the Protein Cycling Diet, I’m guessing this might be a path to faster recovery from injury and intense exercise.

At the end of the 5-day low protein, normal protein levels are resumed. This refeeding is the rebuilding period.


A prolonged fast triggers apoptosis, which is a cellular program that causes a cell to kill itself after becoming damaged. Then the cells are rebuilt afterward. Dr. Longo calls this process the “most powerful generation program since birth.”

For a fast to be prolonged requires 4 to 5 days. This means the intermittent fasting which is just 16-24 hours that promotes autophagy (cell cleaning) is not going to have the same effect. It is still beneficial but in a different manner.


Potential health issues that could benefit from a prolonged fasting diet include:

  • Diabetes
  • Cancer
  • Aging
  • Autoimmune
  • Obesity

And going back to high vs low protein debate in dieting, I would think cycling in a prolonged fast would achieve the benefits of both approaches. Get lean, preserve muscle, and have tight skin. Could it be the holy grail approach? Worth a try.


With a calculator and a calorie website, you could build menus of foods that meet the requirements above. The company ProLon does the math for you and builds food kits to help people stay compliant on this diet. I think that is great, especially for people in poor health.

The simple method recommended is to eat 2 medium sized avocados a day along with some athletic greens. Or if you are super tough, do a pure fast for the time period.

I plan to give the Fasting Mimicking Diet a try in 2018. I’ll keep you posted.


Photo by Charles Deluvio


Add yours

  1. Here´s another way to look at it from the perspective of the protein leverage hypothesis:

    The claim is that all animals eat to obtain a certain amount of protein. For free-feeding humans this usually amounts to 14-15% of total calories consumed. With the onset of fat phobia in the west in the 1930s, the protein content of available prepared foods was reduced along with fat, and their carb content increased. In order to obtain the same number of grams of protein as before, people consumed more total calories per day and their weight increased. Conversely, those who seek to lose weight can eat diets with more than 15% of their calories from protein. This should lead many to a lower total daily caloric intake.

    There are a couple of problems with this approach, as I see it. One is that there is a growing body of evidence suggesting that in all kinds of living species, higher protein increases the odds of cancer growth. Another problem is that although protein is not as insulinogenic as carb, a high protein diet is more insulinogenic than, say, a ketogenic high-fat, moderate-protein low-carb diet. For people who are metabolically damaged, higher protein diets can lead to higher blood glucose levels than keto diets. (And, need I write this? Higher blood glucose levels are unhealthy.)

    I think that your suggestion has merit (not that you were asking for my approval 😉 ) because, presumably, the fasting/fmd can both increase insulin sensitivity and reduce cancer risk. Thus, in theory, we get the benefits of appetite control, weight control, blood sugar control, and cancer risk control.

    [In the paragraph mentioning Ron Mignery I am supposing you meant to write “. . . benefits one can get from very *LOW* protein levels . . .]

  2. @Mike – Thanks for the correction and the article link. That article is extremely interesting, especially how it relates to food choice in a hyper-caloric environment.

  3. Why not a “Potato Hack” for 5 days with 5 or 6 baked potatoes per day? One could employ sweet potatoes which have even less protein than regular potatoes. Rice would work as well! However, the high percentage of fat in Dr. Longo’s FMD is certainly questionable.

    Over 60 years ago in Durham, North Carolina (Duke University), Dr. Kempner certainly improved the health of patients with his rice diet……need I say his diet was low in dietary fat. The potato hack should give similar results as Dr. Kempner. Dr. Caldwell B. Esselstyn’s plant based diet is similar also…..and his famous cry still echos….”No Oil.”

    There has been numerous successful diet paradigms built around plant based high carb, low fat and protein. Dropping the calories for a FMD mimicking effect seems a no brainer.

    Dilly Dilly



  4. @Marc – I had the same thought. Get the limited calories from potatoes and as long as you are under the protein requirements, then it should work in interrupting both the mTOR and IGF pathways. Right? But Dr. Longo mentions a 3rd pathway called PKA.

    The other pathway, which is much less known … is the sugar PKA pathway or RAS/PKA pathway (protein kinase A). Now there is starting to be evidence from our lab and others that this may also be conserved. Meaning that, in addition to the protein pathway, there is also a sugar pathway that is as bad, or almost as bad …

    The more sugar there is available, the more the PKA pathway … gets activated. This gene then in turn can inactivate certain transcription factors … that are very important for protection of the cell, but also for the reprogramming of the cell into a more what we call a maintenance state.

    This would suggest that the fats from avocado would be better than the carbs from potatoes in interrupting this 3rd pathway which is triggered by glucose, not amino aides.

    I’m still learning about this, so if anyone can confirm or correct this information, please post a comment.

  5. So, I started playing with macros. I like to keep things simple. So, if I were to do the fmd, here’s a recipe that I could make with little fuss using frozen spinach, frozen shiitake mushrooms, and olive oil:
    513 grams frozen spinach
    34 grams olive oil
    551 grams frozen shiitake mushroom

    Macro percentages: fats 44.3%, carbs 46.7%, protein 9.0%.

    Of course, if you like fresh, raw food, this won’t work. What I like about doing something like this is that I could, conceivably, prepare it all before starting the fast and then put each day’s “rations” in a separate container. Kind of like paying someone else a few hundred bucks (or whatever) for Prolon, except doing it myself.

  6. @Mike – Thanks for sharing your FMD recipe!

  7. Interesting. I don’t think I had even heard about a nutrition-cancer link 15 years ago. Now we seem to see the (early) signs of a dietary roadmap to minimize cancer risk. (Maybe even a consensus?)

    On the other hand, 15 years ago, I used to hear a lot about the nutrition-heart disease link. Now that link seems to be unclear, and the advice is all over the map and contradictory.

    Cancer always seemed more mysterious and complex than heart disease. Maybe, in the end, we’ll end up minimizing cancer before we do so for heart disease.

  8. @ MAS

    The RAS/PKA pathway is turned one by “Other Factors” also. The pathway is clouded in obscurity of the unknown and unproven. I will wait for further developments before I alter dietary patterns. Furthermore, I found Dr. Mercola’s new book “Fat For Fuel” biased.

    Dr. Peter Attia tells another tale about pathways!

    BTW: 725 calories at a 9/47/44 ratio breaks down to 35 grams of fat, 85 grams of carbohydrates, and 16 grams of protein daily.

    Three to four baked potatoes with 3 tbsp. of butter would come close to providing the above amounts of macronutrients…..and throw in some vegetables with carbs…..carrot/peas. One could make waffles out of a Hungry Jack mashed potato mix to meet the above ratios also.

    @ Jim

    Dr. Nathan Pritikin, and Dr. Walter Kempner have already provided a dietary roadmap to minimize/cure heart disease.


  9. @Marc,
    Looks like mixed reviews for the programs of Drs. Pritikin and Kempner. The Pritikin system has been out for many years, but I haven’t noticed a strong consensus opinion forming around it. Maybe compliance is just too difficult?

    Also, the Internet says that Pritikin died (with clear arteries) of Cancer at age 69? Of course anecdotal, but interesting possiblity if optimizing for anti-heart disease could lead to increased cancer risk, and vice versa.

  10. @ Jim

    True. Strong political and commercial forces have exerted power over truths. In this country (US) we are somewhat free to do our own thing as regards diet. The results of a plant based diet speak for themselves. Look at the blue zones, and please don’t take my words as truth…..look….for yourself. Plant based diets are not sexy and don’t fit into the agenda of the multitude of diet gurus writhing dogmas. After years of poor diet management, any steps toward proper dietary management is going to be difficult to comply. BTW……Pritikin had a reported form of leukemia…..the disease reoccurred…but he did not die of heart disease. There are no facts or any logic that would lead a medical person of clear mind to believe a diet to prevent heart disease would cause cancer.


  11. @Marc
    It seems that much of our nutritional data is messy, contradictary, flawed, and/or promoted by those with a political or financial agenda.
    If such is the case, then a statement such as “There are NO facts or ANY logic that would lead a medical person of clear mind to believe…” seems a bit overstated.

  12. @Jim

    I see no connection between flawed nutritional data, political and commercial interests, and any link of a diet that benefits the heart but would increase cancer risks. The facts are that if one lives to a very old age ….100… cancer still would rank as a leading cause of death. I feel my remarks are based on truth as far as I can see…..and not overstated at all even though I could be proved wrong eventually. I have to disagree with you.


  13. @Marc
    My understanding is that you are absolutely 100% certain in your position that you see no possibility of a link, and that you believe your position is based on absolute objective truth, and that any “clear minded” “medical professional” would agree with you. I guess I’m just more open to different possibilities. Let’s check back in 10 years. 🙂

  14. @All – There are lots of good comments in this thread. I’ve gone down the rabbit hole on some of the links above.

    When I see smart people disagreeing with each other on nutrition, I no longer “take sides”, I now really try to nail down who the audience is for each point of view. Many times the audience of those disagreeing with each other is not the same. When it is the same, I then look to see if they have the same goal. Often they don’t. Things fall inside a healthy umbrella but are different. And in cases where everything lines up and they still disagree, I consider both sides might be right in total or partially.

    This brings me back to the opening idea of this post, which is cycling between two good ideas to get the benefits of each.

    I will be doing a post that better articulates this comment next week.

  15. These are just some random thoughts on this, having only read what is here and the book blurb on Amazon. The thing that is most interesting to me is the pathway that has sugar and is sort of unknown or hidden. This is what causes one to think that the monounsaturated fats in avocados is better than potatoes which are glucose. This reminds me a bit of the idea by Dr. Mark Hyman known as Peganism which he mentions in latest book.

    @Marc, perhaps plant based diets aren’t “sexy” but they seem to be the recurring hotness. I think vegetarianism/veganism is a hot topic for the intelligentsia. A few years ago, Dr. Mark Davis wrote a book entitled “Proteinaholic” which basically espoused a plant based diet and not eating animal fat or protein. It caused a small stir, but then nothing.

    I do think there has been a lot of (mis)information regarding protein and that is coming out especially in the keto diets lately like the idea that Mark Sisson is putting forth in his new book. In the end, it may be enough to get most of our protein from plant sources or reduced animal sources. We can only be our own N=1.

  16. @All – After this post went up, Dr. Longo did an hour podcast with Kevin Rose. In that show, he covers more of his thoughts, specifically his dislike of high-fat diets.

    His new book was just released yesterday.

    The Longevity Diet: Discover the New Science Behind Stem Cell Activation and Regeneration to SlowAging, Fight Disease, and Optimize Weight

  17. Hi, great blog and comments. Am into Day 4 of FMD. As I did not use Prolon, I mimicked their contents instead: organic soup mix, olives, wheat biscuits, two nutbars(day 1 only as I could not find any low sugar bars), walnuts, almonds and hazelnuts. Suprisingly no major pangs of hunger so far. I drank lots of water, some hot green tea and less than one cup of black coffee a day. Energy levels were not bad, some light-headness on Day 3. I stopped my usual activities of weight training, cycling, running and pipe smoking 🙂 Just realised that I need to plan as much for refeeding phase as I did for FMD. If anyone has good tips for refeeding, I’d appreciate your advice!

  18. I forgot to add that I ordered Longo’s book from amazon and have someone to bring it over to me from US. It’s yet to come to me shores in Asia.

  19. I listened to the podcast with Kevin Rose and was a bit disappointed. There was so much bay area/silicon valley woo woo that it was hard to really take Dr. Longo seriously. After that, it seems the idea of a peasant diet would still be superior. All the beans that are eaten by the Blue Zones folks seem like they would have the same trouble as potatoes in that (hidden) pathway that takes up glucose.

  20. @Cathy – There were 2 different diets that were discussed. The FMD which has specific rules that Dr. Longo formulated. And then there is the diet you do the rest of the time. I’m sure from what I heard that the Peasant Diet and potatoes are just fine for that 2nd part.

    I don’t recall hearing any woo-woo from Dr. Longo. Rose was coming from a keto low-carb diet, which Longo critiqued rather clearly.

  21. I think a factor that needs to be considered is Genes, not all people are the same and Genes same to play a huge role in how you react to diets, I did a Keto diet for several months and I did awful on it, my cholesterol was through the roof and the LDL-P was extremely high, the consensus now seems to be that your genes are affected to dietary needs based on what your ancestors ate, if you ancestors ate a high carb diet then you may do poor on a high fat diet and vice a versa, I have a the PPar-Alpha polymorphism and do bad on high fat diet I found out and actually proved it when I went on a high fat diet, I am currently doing a 15 day potato hack and then will ease back into WFPB which I tend to do well on, I got lured by Asprey and BP diet and went off being plantbbased , so I think all these conversations about which diet is best to me seem like nothing if you don’t take your genes as being a factor into the conversation, nobody can tell you what the best diet is only your genes can, Dr Rhonda Patrick has really been a pioneer in this approach

  22. My understanding of an optimal diet when you are past your physical prime is to slow down the growth pathways. This involves mostly to limit protein intake and to exercise. Fat intake should primarily be stable saturated (animal and coconut) with olive oil being second best. I also take supplements which are natural rapalogs to inhibit inflammation and growth. Thanks for all the great information in your blog!

  23. @Rick – I apologize that your comment got flagged as SPAM. I just noticed it this afternoon.

    I agree with your points and thanks for the nice words.

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