by Alejandra "Alex" Ruani — Get free science updates here.
Eat, fast and live longer? Interview with Professor Valter Longo
Professor Valter Longo is considered one of the world’s foremost experts on prolongation of lifespan and longevity.
For over 20 years, he's been studying the complex mechanisms which control aging. He's been featured in Morgan Freeman’s Through the Wormhole: Can we live forever?, Dr. Michael Mosley’s BBC Horizon Programme: Eat, fast and live longer, and his recent book: The Fast Diet, co-written with lifestyle journalist Mimi Spencer.
Prof. Longo's work and discoveries are labelled as some of the greatest achievements in science.
For example, did you know that his lab mice hold the world record for longevity extension in a mammal? And when it comes to humans, he challenges other experts to show him an even better way to trigger the most extreme metabolic changes that he currently evidences with a 4-day fast.
I have been in touch with Professor Valter Longo for a long time, even before The Fast Diet book was published. Here's a transcript of my interview with him:
Alex Ruani: So what exactly are the key metabolic changes and biological benefits of a 4-day fast?
Valter Longo: There are hundreds of changes. The major ones are decrease in IGF-1, decrease in insulin, decrease in glucose, increase in ketone bodies and IGFBP1.
Alex Ruani: How would you explain the connection between IGF-1, DNA damage and aging?
Valter Longo: IGF-1 is like an accelerator that promoted excess activity of cells, even when they don’t need to be hyperactive. Cellular hyperactivity is associated with oxidative stress and DNA damage.
Alex Ruani: By how much would your IGF-1 levels normally decrease with a 4-day fast?
Valter Longo: Most people would see a major reduction. However, IGF-1 and other markers go back to normal or close to normal if the person returns to the old diet. Some benefits will remain but only in association with a longevity diet, in which case the effects of fasting are maximised. Remember that a 4-day fasting should only be done under the supervision of a registered doctor.
Alex Ruani: How exactly did you come up with the idea of a 4-day fast?
Valter Longo: It is the minimum time required to switch to a full speed protective and fat burning profile that involved every single organ in the body: from the intestines to the brain.
Alex Ruani: It seems that a 4-day fast would help reverse biological aging, but do you think it would it also help you look visibly younger – i.e. physically and aesthetically? (Important point for women; and I do think you look much younger for your age!)
Valter Longo: Hard to be sure until we do additional studies. Many people who fast for long periods claim that they can see a clear difference, including the skin.
Alex Ruani: A Google search on HGH (Human Growth Hormone) typically comes up with links suggesting that higher levels of it promote youth and beauty. How accurate is that?
Valter Longo: Very inaccurate. Human Growth Hormone (HGH) is one of the most potent pro-aging factors. However, it is possible that in elderly individuals with very low HGH levels some HGH may be beneficial.
Alex Ruani: What happens with HGH when you carry out a 4-day fast? What are the benefits of changes in HGH levels?
Valter Longo: Growth hormone (GH) controls IGF-1. The GH/IGF-I axis is turned down during fasting. This is well established to promote anti-aging and disease prevention effects.
Alex Ruani: Would a short 4-day fast be safe for the healthy adult?
Valter Longo: Only under medical supervision and not for diabetics or subjects with hypotension or metabolic disorders.
Alex Ruani: If you are a healthy adult, would it be okay to do a short 4-day fast on your own?
Valter Longo: No, however it may be possible to do it after it is done several times under doctor supervision and if the doctor feels it is safe to do it without supervision.
Alex Ruani: What are the risks associated with fasting for longer than 4 days?
Valter Longo: Many risks. For example, accidents related to reduced blood pressure.
Alex Ruani: You have fasted for 4 days several times. Does it ever get easier?
Valter Longo: Yes, much easier after the first time.
Alex Ruani: What’s the toughest part of a 4-day fast for most people?
Valter Longo: Being away from food. We are so used to having food all the time that we cannot conceive separating from it. This is one of the most important factors. Some people call this the “spiritual component” but I think it is about taking charge of your nutrition and health.
Alex Ruani: We hear that the first fasting day is the toughest. Does it get easier later on?
Valter Longo: Yes. It gets easier by day 3 because your body adapts to burning primarily fat instead of sugars.
Alex Ruani: What liquids would you normally consume in your 4-day fast?
Valter Longo: Teas, broth, bouillon, instant soup. But calories should stay under 200 a day.
Alex Ruani: Would you need to take multi-vitamin complex or supplements?
Valter Longo: No, but you need to be very well nourished before you start and after you finish. Subjects who are malnourished or lack essential micro-nutrients and undergo fasting are at risk for severe health problems and possibly death.
Alex Ruani: Do the fast days go faster if you keep busy?
Valter Longo: Yes. For example, fasting clinics like the Buchinger Clinic in Germany ask subjects to do light exercise for several hours a day.
Alex Ruani: Is exercise during fasting advisable then?
Valter Longo: Yes, but only light exercise. Strenuous exercise can cause fainting.
Alex Ruani: Would a healthy adult lose weight during a 4-day fast?
Valter Longo: Yes, a few pounds, depending on the individual.
Alex Ruani: Would most people put it back on again, or is it possible to maintain it?
Valter Longo: Most people gain it back. However, if fasting is combined with a particular diet tailored to the individual, periodic fasting is very effective in promoting weight loss. After many of the cancer patients we were following asked for diets that could substitute fasting, I founded a company (L-Nutra) which received funds from the US National Cancer Institute to develop fasting-mimicking diets. Our plan is to have these available world-wide within the next few years.
Alex Ruani: Does this require supervision too?
Valter Longo: Yes, the L-Nutra 5-day diet will require some supervision, but this could be done by a registered dietician or nutritionist. Our plan is to establish an international network of health professionals who we can work with and keep informed to allow them to optimise the health of their patients while keeping costs low for them. The visits could be as often as once a week for subjects with severe problems to once every 6 months for subjects who are very healthy and informed. It is very easy to become malnourished or over nourished, so it is key to work with a health professional. However, I often hear complaints about finding health professionals that are properly trained and keep up with the scientific and clinical literature and with the legitimate "alternative strategies".
Alex Ruani: Training for the health professionals is indeed much needed. Our work at The Health Sciences Academy brings doctors, nurses and nutritionists up to speed with the latest science and provides them with CPD training.
Valter Longo: We’re planning to do something similar. When Harper magazine interviewed me for a piece on fasting, I made this point to the journalist who was himself undergoing a 3-week fast while writing the piece, and he told me "Valter, the doctors you are talking about are impossible to find". Although there are already a lot of prepared doctors out there, we hope to help change this by training them through new "Nutrition and Longevity" programmes which will be available online through distance learning.
Alex Ruani: That’d be great. We can help you with that at The Health Sciences Academy. Talking about longevity, how do you link the foods we eat with how we age?
Valter Longo: Each food component activates difference genes and pathways. For the past 20 years, we and other researchers have learned a lot about these connections so now we can start applying them to obtain maximum effects with limited burden.
Alex Ruani: Would you say it is wise to avoid any kind of meat? Or just red meat?
Valter Longo: This is a difficult question to answer. If most people did that, they would probably become malnourished. However, if someone thinks they may enjoy a plant-based diet, they can follow it with the help of a nutritionist or doctor to make sure they do not become malnourished. A plant-based diet is by far the best for longevity and disease prevention.
Alex Ruani: That’s a great way to conclude this piece. Thanks very much Valter!
IMPORTANT: A plant-based diet is not a synonym of veganism. From our perspective, it just means that most of the foods you eat come from plant-based sources. We take this approach in our Nutritional Therapist course. Also, our Dietary Supplements course teaches health professionals how to avoid malnourishment either through whole foods or supplements.