Benefits of Intermittent Fasting With Valter Longo, Ph.D

Interview With Valter Longo About The Benefits Of Fasting 

Fasting has been promoted for various reasons for centuries, but it’s only recently that researchers have been able to investigate the health benefits from doing strict fasting for days at a time.

Fasting is thought to induce various changes in the body that help protect the cells from damage that may occur from the environment, and trigger pathways in the body which may increase health and possibly lifespan.

My own experience with fasting

Fasting is something that I’ve done over the years in many forms. I’ve restricted my eating to only a few hours of the day and had long periods where I didn’t eat for up to 16 hours. I’ve fasted for one day of the week for 24 hours for many years. I’ve found that fasting seems to me mentally, to help me focus better.

It was always difficult to objectively tell whether or not fasting was helpful to myself, because I’ve done calorie restriction for such a long time, and this by itself has very good results in terms of improving health markers and improving health.

Fasting has always been pretty easy to to do for me, but I’ve found calorie restriction to be just easier. Not only that, calorie restriction has a lot more data to back up the health and longevity benefits.

There is no doubt that fasting is beneficial to health, but it’s still up for question whether or not it can really extend lifespan significantly without any reduction in calories. That being said, people who fast, may automatically have their caloric intake reduced anyway.


The Interview

Dr. Rhonda Patrick speaks to Valter Longo, who was a student of the calorie restriction researcher and pioneer Roy Walford. During the last few years, he has demonstrated that prolonged fasting is able to rejuvenates the immune system so that it is in a more youthful state, as well as induces anti-cancer effects, and helps prevent side effects from cancer therapies in humans. He also mentions how fasting may improve the health or even cure people with autoimmune diseases such as multiple sclerosis. I’ve previously shared one recent study showing how fasting rejuvenates the immune system.

Valter Longo has recently written a book which is not yet available in English. I was just made aware that an English version of his book The Lonevity Diet will be available in January 2018. I’ll be sure to write a review of it when I receive a copy.

Related articles: Is fasting good for you?

Fasting Rejuvenates The Immune System!


I’ve written about the benefits of fasting before and do recommend fasting on occasion to improve your health. As part of my healthy lifestyle, I fast at least one day per week, usually on the weekend. It’s sort of become routine now, so I don’t really find it that difficult. On my fasting day I will just drink a lot of green tea! Like 10 – 15 cups. 🙂 Some people might have problems with drinking green tea on an empty stomach though, because the tea contains tannins, which can cause a little bit of nausea.

So, a new study was just released in the journal Cell showing that fasting has remarkable effects on the immune system. It seems that just fasting for one day is not enough to induce a strong response either – one would need to fast between 2 – 5 days!

The study found the following changes occurred after repeated fasting cycles

  • Fasting downregulated the IGF-1 / PKA pathway in stem cells
  • Fasting protected cells from the effects of chemotherapy
  • Fasting promoted stem cell renewal and reversed chemotherapy induced immunosuppress

Initially the fasting caused a drop in white blood count, but then after re-feeding, the white blood count was increased to normal levels. This has effect has also been observed in animals and people on calorie restriction and is one of the reasons why it’s important that you get a full blood count test before starting the diet so that you can get a baseline number. I noticed my own WBC drop after starting calorie restriction – especially lymphocyte count.

In the past researchers have shown that when mice are fasted before given chemotherapy or radiation treatment, they are able to survive much higher doses without any negative effects. This study confirmed what has been found before – fasting protects the mice from chemotherapy drugs. In fact, 100% of the mice that were fasted survived compared to just 40% of the animals that weren’t fasted [Figure 1B]. They also noticed that the lymphocyte count was normalized in the fasted mice. In animals, and probably humans, repeated cycles of fasting can rejuvenate an immune system that has been damaged from toxic drugs or ageing.

What the researchers investigated

They were looking at quite a few things: The effect of prolonged fasting on mice exposed to chemo therapy and looking at the level of apoptosis to a subpopopulation of cells ( LT-HSCs, ST-HSCs, and MPPs) after 6 cycles of prolonged fasting (PF) + Chemo (CP) or chemo alone. Compared to just chemo, they saw that prolonged fasting was able to have a significant effect on preventing cell death. The researchers looked at the length of time it took to recovery of lymphocyte count in control mice and found it took 70 days (6 cycles ) before recovery was seen; but in the fasted mice, the count was decreased independently by the fast and recovery of lymphocyte count was seen earlier at day 40 (cycle 4) probably because of the increased resistance to apoptosis of progenitor cells. By cycle 5 the fasted mice displayed a more normal lymphocyte / myeloid ratio as well, indicating higher resistance to the toxic effect of chemo.

In a separate experiment they were looking at the effect of fasting on old mice and populations of LT/ST – HTCs after 8 cycles of fasting. The researchers noted a temporary drop in white blood count during fasting, but an increase, over time, in HSCs above that of Young-AL & Old-AL mice. There was an increase to normal youthful levels because of the shift in balance by the end of cycle 8. A rejuvenation effect of the immune system. This is a very important and profound result!

Phase 1 trials on human have been completed. Cancer patients noticed less symptoms associated with chemotherapy when they were fasted for up to 72 hours before treatment. The effect on PF + CP on humans is quite dramatic as it almost ameliorated the significant drop in chemo induced lymphocyte count as you can see in the table S1 in the supplementary data in the paper [1]. Researchers are currently planning phase 2 clinical trials to expand their research onto larger randomized groups of people.

This is an extremely exciting area of research and something we can learn from and apply today. I wouldn’t personally try to fast for 5 days as 3 days seems to be sufficient. I’m considering trying to do a 3 day fast, once per month, in addition to my 24 hour fast each week. I’ll let you know when I start! 🙂

Watch one of the researchers of this study talk about the benefits of fasting on cancer


[1] Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression

Is Fasting Good For You?


People do short fasts and long fasts for many reasons. Some claim that it helps to reduce the risk of disease, to clean out toxins from the body; while others do it for spiritual and religious reasons. I’ve had quite a lot of experience with short fasts of about one to three days, but never more than this. Is there any benefit going beyond this?

In 2007 I experimented with fasting by consuming most of my calories early in the day and creating a cut-off point where I wouldn’t eat beyond a certain time. So I would wake up by 7 am and consume all my calories for the day by 2 pm. Although it’s going back a bit, I remember feeling a lot more alert, and I could fall asleep faster and sleep better. Aside from the growling noises in my stomach  — which usually came on at the most inconvenient times  — the long fasts each day were pretty easy for me to because at the time I had so much going on with college and work, I didn’t have much time to think about food. I guess I’ve always found any kind of dietary pattern very easy to adapt to. Even when I was consuming a mere 1550 Calories per day for several years, I didn’t find it too difficult. After about 5 years I decided to increase my calorie intake so that I could increase my BMI a little and be safe; as I thought having such a low BMI was too risky at that time. I did this experiment where I would stop eating early in the day for about a year, and then returned to my normal pattern of eating.

Using fasting to maintain a low calorie diet: In the last few years I have settled into just fasting one day a week. This not only gives my body a rest, but it helps lower the average calorie intake across the week if I had eaten too much on any particular day. In animal studies, it is the total calorie intake that matters when it comes to slowing down ageing; not when the calories were eaten. I find this method very effective and easy to do and makes it even easier to maintain a low calorie diet.

Benefits of Fasting: As for the health benefits of fasting, yes, they do exist! But you do not have to fast for a crazy amount of time to get them. When a person fasts, their body releases certain hormones such as Ghrelin, which stimulates appetite and has many beneficial effects around the body such as:

  • Increased motivation
  • Reduced anxiety and depression
  • Protective against neurodegenerative diseases
  • Enhances learning and memory 


When you fast you also increase the production of a protein called Brain-derived neurotrophic factor (BDNF). This protein is also increased when a person is on a calorie restricted diet or is exercising. The beneficial effects of BDNF are primarily:


  • Enhanced learning and memory
  • Protection against neurodegeneration diseases; Alzheimer’s and Parkinson’s
  • Increased neurogenesis (creation of new neurons in the brain)

Back in 2012 there was an excellent documentary called Eat, Fast, and Live longer. Michael Mosley investigated the research behind calorie restriction, fasting, and ageing. He travelled around the united states to speak to researchers who are at the cutting-edge of ageing research to find out which is the best way to reduce the risk of disease and possibly slow down ageing. During the show he spoke to Mark Mattson who is an expert in his field. He explained how beneficial fasting is for the brain and how well it delays the onset of Alzheimer’s disease in mice that are destined to get it an an early age. To speed up the onset of Alzheimer’s disease, the researchers put Fructose in their drinking water. The mice on the high sugar diet without being fasted developed the disease earlier than the mice that were fasted! Hear about the incredible results in the video below!


Although fasting is greatly beneficial to our health, there is no need to take it too far. One or two days is more than sufficient to get the benefits. Prolonged fasting can be dangerous to one’s health, especially to the heart. In one study conducted on rats, they showed that every-other-day fasting caused diastolic dysfunction The heart became stiff and did not relax properly. They also showed reduced systolic pump function. So be careful with prolonged fasts. One day is totally fine and will not hurt you. There is no need for 1 week fasts.  I am currently writing a much more detailed review on fasting, but today I thought I’d just create a short overview of the benefits and risks of fasting.



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2. Protecting new neurons reduces depression caused by stress.

3. Meyer RM, Burgos-Robles A, Liu E, Correia SS, Goosens KA (October 2013). “A ghrelin-growth hormone axis drives stress-induced vulnerability to enhanced fear”. Mol. Psychiatry. PMID 24126924

4. Diano S, Farr SA, Benoit SC, McNay EC, da Silva I, Horvath B, Gaskin FS, Nonaka N, Jaeger LB, Banks WA, Morley JE, Pinto S, Sherwin RS, Xu L, Yamada KA, Sleeman MW, Tschöp MH, Horvath TL (March 2006). “Ghrelin controls hippocampal spine synapse density and memory performance”. Nat. Neurosci. 9 (3): 381–8. doi:10.1038/nn1656. PMID 16491079

5. Wenzhen Duan*, Zhihong Guo*, Haiyang Jiang*, Melvin Ware†, Xiao-Jiang Li‡, and Mark P. Mattson. Dietary restriction normalizes glucose metabolism and BDNF levels, slows disease progression, and increases survival in huntingtin mutant mice
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7. Ahmet I1, Wan R, Mattson MP, Lakatta EG, Talan MI. Chronic alternate-day fasting results in reduced diastolic compliance and diminished systolic reserve in rats. J Card Fail. 2010 Oct;16(10):843-53. doi: 10.1016/j.cardfail.2010.05.007. Epub 2010 Jul 1.