I Tried a Fasting Mimicking Diet
Fasting has profound health benefits but who wants to go days without eating?! Introducing the Fasting Mimicking Diet — a novel approach to promoting longevity.
If you follow me on Instagram, you know that last week I embarked on something a little out of the box.
I tried the “Fasting Mimicking Diet.”
FYI – I was NOT paid to do this.
I was afraid when I shared what I was up to that some would think I’d fallen victim to one of the many fad diets out there.
Let me tell you — the Fasting Mimicking Diet is not a trendy weight loss diet, or a cleanse, or like anything you’ve ever heard of before. Its premise is supported by research from all over the world with potentially life-changing benefits.
It is so much bigger than weight loss. It is about longevity.
It is about matching your healthspan (years lived free from disease) to your lifespan.
Yes, you will likely lose some body fat, but to call it a weight loss diet is to miss the point entirely.
Dr. Valter Longo + The USC Longevity Institute
I first heard the term “fasting mimicking diet” while taking a course on genes and longevity with Dr. Valter Longo in Italy last summer as a part of my dietetics program.
Longo is a biogerontologist with decades of research under his belt and is credited with helping discover pathways in cells that regulate aging. He is the Director of the Longevity Institute at the University of Southern California and is, in no better words, a rock star in the field of aging.
Still, like many of you I’m sure, my first thought was, “What is this nonsense?”
After listening to Longo lecture passionately, authoritatively, and at many times way over my head, about the colossal amount of research supporting fasting for health and longevity, and inundating our class with a mountain of peer-reviewed studies, I quickly learned that this so-called “diet” was anything but nonsense.
My mind was blown.
The Science Behind Fasting
In short, fasting and caloric restriction have both shown to significantly extend lifespan and prevent or reduce chronic disease in many organisms by activating pathways that put cells in a “protective mode” in which stress resistance, DNA repair, and autophagy (when cells “self-digest” dysfunctional components) are increased (1).
It’s fascinating. Basically, cells respond to the stress of fasting by becoming stronger!
In mice, caloric restriction can extend lifespan by 50% (1).
Can you imagine the average person living to 120 instead of 80?
However, a lifetime of caloric restriction would not only be impossible (and totally miserable) for most people, it could also be harmful, potentially causing reduced immunity, poor wound healing, and decreased reproductive function(1).
That’s where fasting comes in. Fasting achieves many of the benefits of caloric restriction but without the adverse side effects.
As opposed to chronically restricting calories, with fasting the period of restriction is followed by a return to a normal diet. And in fact, this “refeeding” period is actually just as important as the fast. It’s during this time that cellular regeneration occurs (2). In mammals, fasting produces a coordinated, system-wide major reduction of white blood cells, which is followed by regeneration of hematopoietic stem cells (2).
Stem cells give rise to all other cells in the body — red blood cells (energy production), white blood cells (immune system), and platelets (blood clotting). They are important for replacing old, damaged cells and regenerating tissue, and their production decreases with age. Some experts believe that the reason we age is due to a decrease in the regenerative capacity of these cells, which leads to chronic disease.
So, the ability to regenerate stem cells through fasting is pretty remarkable. However, straight water fasting can be dangerous and pretty unbearable for the majority of people.
That’s why Longo and his team starting experimenting with fasting mimicking diets.
What Is A Fasting Mimicking Diet (FMD)?
Through years of research, Longo and his team found that the benefits of fasting are produced by the restriction of specific nutrients — protein and glucose — that activate pro-aging pathways (mTOR and PKA for my science nerds out there), and that restricting these nutrients mimics effects of fasting while still providing some nourishment (2, 3).
In simple terms, your cells are constantly receiving signals from hormones in the body based on nutrient availability. Hormones like insulin (triggered by glucose) and insulin-like growth factor-1 (aka IGF-1, triggered by protein) tell your cells to grow and reproduce (4). The absence of these signals triggers the opposite response — rest and repair.
In mice, cycles of FMD have shown to:
• Reduce cancer incidence (3)
• Prevent bone mineral loss (3)
• Promote neurogenesis (3)
• Stimulate stem cell production (3)
• Protect from chemotoxicity (2)
• Regenerate beta cells in models of Type 1 and Type 2 Diabetes (6)
• Remyelinate neuron sheaths in models of Multiple Sclerosis (7)
• Extend lifespan (3)
These remarkable results set the stage for the creation of an FMD for humans. Longo and his team used what they learned in mice to create the ProLon® Fasting Mimicking Diet™.
While they haven’t tested it in humans with chronic diseases yet (although a clinical trial in cancer patients is underway), they did a large clinical trial last year on healthy adults and were able to lower markers of chronic disease with three cycles (8).
The results showed:
• Lower cholesterol
• Lower blood pressure
• Lower levels of C-reactive protein, a marker of inflammation
• Lower IGF-1 hormone, which is what fuels the mTOR pro-aging pathway
• Reduced visceral fat stores, which are also associated with chronic disease
The reduction in visceral fat (fat stored around organs in the abdominal region) was accomplished without a reduction in lean body mass, which is usually a concern with low-calorie diets.
What is the ProLon® Fasting Mimicking Diet™?
The Fasting Mimicking Diet™ is a low-calorie, low-protein, low-carbohydrate, high-fat, 5-day plant-based meal plan that tricks your body into thinking it is fasting so that it may enter a cellular protection and regeneration mode while still receiving all of the essential nutrients.
While the diet is intended to produce a state of nutritional ketosis, it differs from your typical “Ketogenic Diet” in that it is not just low in carbohydrates but also low in protein (~10% of total calories). As noted above, a reduction in protein is necessary in order to reduce IGF-1 and trigger regenerative cellular effects (5).
The diet comes in a box with all of the food you are to eat for the five day period, including soups, nut bars, tea, kale crackers (which are actually super tasty), olives, algae oil, an “energy drink” (I explain more about that in my video), and micronutrient supplements.
The diet ranges in caloric content from about 1100 calories the first day to 700-800 the next four days.
What’s Next For Fasting/Fasting Mimicking Diet Research?
USC is currently conducting a phase II clinical trial on breast and prostate cancer patients at Norris Cancer Center and LA County Hospital using another FMD called Chemolieve®. It is specifically formulated for cancer patients and is intended to reduce the adverse effects of chemotherapy and enhance cancer cell death, through a mechanism known as “Differential Stress Resistance” (9).
I had the opportunity to work on the trial during my dietetic internship and the research they’re doing is extremely exciting.
However, ProLon® is not approved by the FDA to treat or prevent any disease and is only currently intended to promote longevity.
FYI, Longo does not benefit financially from sales of Prolon®. He puts all of his earnings in the company back into his research at USC.
So Why Did I Try a Fasting Mimicking Diet?
I want to live a long, healthy life!
I want a healthspan to match my lifespan.
My maternal grandmother died at the age of 52 from colon cancer. I was only two at the time, and I never got to know her, but it was very hard on my mother as they were extremely close. My grandmother’s sister also passed away from the colon cancer at an early age, and both of my paternal grandparents died in their 60’s of heart disease.
Cancer and cardiovascular disease run in my family. I don’t need to live to 100, but I do want to live long enough to see my children’s children and to live those years free from chronic disease.
I trust the research. And it shows that the Fasting Mimicking Diet is one of our best ways to promote longevity.
My 5-Day Fasting Mimicking Diet Video Diary
So, you want to see what five days on the diet was like? Check out my FMD video diary – fast forward to 2:39 to skip the intro. >>
Tips for Trying A Fasting Mimicking Diet
If you plan to try ProLon®, here are a few tips to help you through:
• Do it with a friend. Sticking to the diet can be challenging, but having a support system to provide resolve and encouragement makes it easier. Shout out to my husband for doing it with me!
• Stay hydrated. Your body can mistake thirst for hunger. Don’t put yourself at an added disadvantage by becoming dehydrated. Drinking a lot of water and decaffeinated tea throughout the day was very helpful for me.
• Buy a bunch of caffeine-free tea or try something like Teeccino if you’re a coffee-fiend like myself. While you are technically allowed one cup of coffee a day while on Prolon, researchers believe to achieve the maximum effect, you should avoid it.
• Stay busy. The more your mind is engaged in activities, the less time you’ll be thinking about food. Read a good book, go for a walk, chat with friends, stay out the kitchen!
Longo recommends healthy adults do the diet 1-2 times a year, and those with biomarkers for chronic disease do it up to monthly. I feel so strongly about the benefits of fasting and the promise of the fasting mimicking diet that I will definitely do it again soon.
Use my code: WHITNEYERD10OFF to get $25 off your first box.
*Disclaimer: The information on this website is not intended to serve as medical advice. The statements on this site have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. The Fasting Mimicking Diet may not be right for everyone, certain conditions preclude the use of this diet. Talk to your doctor or dietitian before beginning any new diet.
**I was not paid for my review or promotion of ProLon; however, I do receive a small commission on sales of the product. I thank you for your support of partnerships that support the operation of this blog.
References:
- Fontana et al. (2010). Extending the Healthy Lifespan – From Yeast to Humans. Science 16, 321-326.
- Cheng et al. (2014). Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression. Cell Stem Cell 14, 810-823.
- Brandhorst et al. (2015). A Periodic Diet That Mimics Fasting Promotes Multi-System Regeneration, Enhanced Cognitive Performance, and Healthspan. Cell Metab. 22, 86-99.
- Longo et al. (2015). Fasting: Molecular Mechanisms and Clinical Applications. Cell Metab. 19, 181-192.
- Fontana et al. (2008). Long-term Effects of Calorie or Protein Restriction on Serum IGF-1 and IGFBP-3 Concentration in Humans. Aging Cell 7, 681-687.
- Cheng et al. (2017). Fasting-Mimicking Diet Promotes Ngn3-Driven β-Cell Regeneration to Reverse Diabetes. Cell 168, 775-788.
- Choi et al. (2016). A Diet Mimicking Fasting Promotes Regeneration and Reduces Autoimmunity and Multiple Sclerosis Symptoms. Cell Reports 15, 1-11.
- Wei et al. (2017). Fasting-Mimicking Diet and Markers/Risk Factors for Aging, Diabetes, Cancer, and Cardiovascular Disease. Sci. Transl. Med. 9, eaai8700.
- Raffaghello et al. (2008). Starvation-dependent differential stress resistance protects normal but not cancer cells against high-dose chemotherapy. PNAS 105, 8215–8220.
- Song et al. (2016). Association of animal and plant protein intake with all-cause and cause-specific mortality. JAMA Intern. Med. 176, 1453-1463.
Not ready to try a fasting mimicking diet? Switching to a more plant-based diet is another effective way to reduce biomarkers of chronic disease (10).
Start by trying one of these delicious, vegan recipes! >>
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Weigh in: Are you interested in learning more about fasting or the research on fasting mimicking diets? There is SO MUCH MORE out there. I can go in depth into specific conditions if you are interested. Let me know in the comments below!
Amanda Howard says:
Yes – please go more in depth! I could read or talk about health, the body and nutrition all day, everyday! This was the most facinating blog post ever and I love the Healthspan/Lifespan equation to promote longevity. Longo pouring all the money back in is just so wonderful. This is an amazing post! Well done on making it through and that you plan to do it again soon – wow! Great video diary of your 5 day FMD too.
dixya @food, pleasure, and health says:
i have always been curious about fasting from a cultural/religious point of view..I am interested to learn more about this and the research in general.
Lindsay says:
I was following you doing this on Insta and was so interested by it. This is a really great, in-depth explanation that makes sense. I am so interested in trying this!
Ellen says:
Interesting! So far I’ve been sticking with wine for anti-aging;)
Although seeing as I’m someone who will go all day without eating then eat a lot before bed I think I’m an accidental intermittent faster, so would be curious to hear more about fasting…
Whitney English says:
Those polyphenols are great antioxidants! Glad to hear you’re interested in doing more. I will do a post on the difference between intermittent fasting (IF) and periodic fasting (which is what this and water fasting are) sometime soon!
Nicole says:
Can you share the approximate cost? It looks like on the website you have to get signed up with a health care provider or have an HCP code, but I’d like to have an idea of how much this investment is so that I can plan accordingly.
Whitney English says:
Of course! It’s $299 but if you buy 3 (so doing it 3 months in a row, which is what the participants in the clinical trial did) it comes down to $250 each. Then you can use my code ENG10 for 10% off that.
Troy says:
Or you can do it for about $30. Too long for a comment, but I broke down the nutrients, and recreated it myself. Morning 2oz of cashews. Lunch salad with 2 cups each of spinach and kale. 1 cooked beet, large slice of onion, 1/2 a red pepper, and 2 tablespoons of olive oil… Add some vinegar, salt and pepper. Supper was 1/4 cup of black beans with 1 tablespoon of avocado oil. About 1090 calories, and all the nutrients in Longo’s diet. Days 2-5 are between 700-800 calories, with similar foods. Save yourself hundreds, and just do the math… Unless you have money to burn.
Suze says:
Thank you for the inspiration Troy. I’ve wanted to break it down myself, but it has seemed too daunting for me. Your menu sounds quick and easy. Maybe it’s not as hard as I thought.
Patti Cakes says:
Very informative and interesting! Love the way you condensed a lot of information.
Bridget @EatRightMama says:
Whitney, your post and video diary were fascinating! I’ve never thought I could do a fast but the FMD is a definite possibility!
Lauren O'Connor says:
I’ve been wanting to delve into the research on this. Great info Whitney! And I love your video.
Abbey Sharp says:
Thanks for the super informative post! I saw your video on this as well, and really enjoyed it!
Betsy Ramirez says:
Fascinating read!
Caity @ Moi Contre la Vie says:
I’m DYING to try this!! Quick question – Did you workout at all during the 5 days?
Whitney E. RD says:
No, I didn’t. Exercise is not recommended while on the FMD. However, some light yoga/stretching or walking is likely fine if you’re feeling good!
Melodie says:
There has to be a way to do this without a $300 box of prepackaged foods. Right? Does Longo’s book guide you in creating this 5 day fast at home on your own?
Caroline Wilhite says:
Yes, his book does have a diy program.
Alicia says:
thank you for the informative post Whitney – You mentioned you could speak to specific diseases – curious if you have any information on FMD and Hashimotos?
THANK YOU!!!!!
Whitney E. RD says:
There are not any human or animal studies that I’m aware of but in the studies they have done on other autoimmune disorders like MS and T1DM, they’re seeing promise. Talk to your doctor about it!
Sofia says:
This is such a thorough and informative post on the FMD, thank you! I found your blog last month after reading Dr Longo’s book and looking for more information online. Your blog is a great resource for people looking for evidence-based dietary advice, wish there were more dieticians who shared your views. As a mother and health-care provider I appreciate the info you provide, the recipe guides, and I found your youtube channel and enjoyed your interview with Dr Longo, great work!
Whitney E. RD says:
Thank you so much for the kind words, Sofia! I appreciate your support!
John says:
Hi Whitney,
My day 2 seemed like your day 3. Your husband also seemed like he had a bad day 2. Apparently day 3 is typically the bad day for people. Any ideas as to why the variation for that?
Also, I took fat readings with an Omron Fat Monitor the morning of day 1, and day 6 (transition day). While I lost 6 lbs, my fat percentage went up 2%. The highest readings I’ve ever had. Any thoughts on that?
Whitney E. RD says:
I’m not sure what to make of the fat reading! And unfortunately, I don’t really know why there is variation in people’s physiological response. I would guess it just has to do with our individual differences and the timing of when our body actually transitions to ketosis.
Rebecca says:
Thanks for sharing, Whitney!! I too love coffee, and teeccino is OK but not the same. Do you think decaf coffee would be allowed with FMD or is there something about coffee (both regular and decaf) that interferes with the diet?
I’m actually just finishing Day 3 of the FMD. I’m excited to be done in 2 days, but would definitely consider doing this again! It would be awesome to be able to add in decaf coffee next round :).
Thanks for your input!
Whitney E. RD says:
It’s hard to say! Decaf would technically be “allowed” but we really don’t know what could affect the fast since these things haven’t been tested.
Erin says:
Thanks for sharing this, I have completed one round but I had 1 coffee a day. Didn’t see the benefits I was expecting so I figure it must have been the coffee. I’m starting my next round in a few days. I see you recommended chicory drink, I have this at home . Can I ask how you can be sure this does not negatively impact the fast ? Thanks in advance
Erin
Whitney E. RD says:
I can’t be sure – unfortunately, there are still many unknowns about the physiological effects of fasting and nutrient-sensing pathways.
VIRGINIA WALSH says:
Hello Whiteney:
I have a few questions with regards to the role you, as an R.D., have with the fasting mimmicking diet program. As a vegan R.D., myself, I am excited about the many benefits of the fasting mimmicking diet. What training have you received from Prolon??? I have contacted both the Valter Longo Foundation and Prolon customer service trying to get feedback re.training for dietitians without much success. I have registered for the training webinars with Prolon. With “relatively serious illnesses” requiring “dietitians with expertise in the FMD or in therapeutic fasting” I am needing training to participate in its use in Canada. Can u shed any light on this subject.? What a great tool also to assist individuals in
moving towards a healthier diet whether it be semi-whole food plant based diet,
pesco-vegetarian diet or even a WFPB diet.
Nutritionally yours,
Virginia Walsh R.D.
VIRGINIA WALSH says:
Unfortunately as I am using my cell phone to send this email the print is very tiny and I didn’t notice that I spelled your name wrong my apologies
Jack says:
This is quite intriguing as I’ve been a holistic advocate for more
Than 35 years. I was wondering if there’s a list of dieticians or doctors that practice this program and can help with its integration into my life I’m in Raleigh NC area. Zip 27540. Is there any listing of practitioners by zip code.
Nika Ramos says:
Whitney, I was just diagnosed with invasive ductal carcinoma. And I have seen the research for FMD and cancer and really want to do it before and while I stay my chemo but I know it’s not FDA approved. So I don’t know how to get it. Do you have a connection to be apart of the trial study?
Whitney E. RD says:
Hi Nika, I’m so sorry to hear about your diagnosis. Anyone can buy Prolon – the 5-Day Fasting Mimicking Diet, although keep in mind that they can’t sell it to you without your doctor’s approval if you indicate on the welcome questionnaire that you have a chronic disease. In the cancer trials, they’re using a product similar to Prolon called Chemolieve. It has a similar composition but much lower calories. The trial is going on at MD Anderson in Texas and LA County Hospital. FYI, 4 days of water fasting has been shown in pre-clinical trials to be safe in conjunction with chemo (and it’s free). Make sure to talk to your doctor before trying any of these protocols though.
tracy Gibson says:
I am on day 2 of the ProLon FMD. I loved watching your video and would love any links or info via e mail >. Thank you ! Tracy
Claudia says:
Hi,I live in the uk and have been doing fmd now for 2 years,I did it 4 times last year spread over the year, this year after reading research I have decided to do it every month for 3 months and then again in sep or Oct, I have broken down the nutrients too and have my own menu which I stick too and drink lots of yogi decaffeinated herbal teas which taste yummy. I really enjoyed reading your story and I’m so pleased you get it,I wish more people did I really hope this keeps me healthy till the end :))
Claudia
Whitney E. RD says:
Thank you for sharing your experience Claudia!