Fasting Diet

Fasting Mimicking Diet Could Fight Disease, Increase Longevity: 9 New Questions for Dr. Longo

Dr. Valter Longo is the Edna M. Jones Professor of Gerontology and Biological Sciences, and director of the Longevity Institute at the University of Southern California-Davis School of Gerontology, Los Angeles, where his studies focus on the fundamental mechanisms of aging. We sat down to discuss his new book The Longevity Diet  and the number one diet mistake people tend to make.


1. You’re known for your groundbreaking research in the science of longevity. Can you give us the most important discovery or discoveries in the science of aging that you unveiled in The Longevity Diet?


  • The discovery of a Fasting-Mimicking Diet that can be done for as little as twice a year for five days, in which mice had major changes on lifespan, lower rates of cancer and other diseases.
  • The discovery of two of the most important pathways now widely recognized to regulate aging: the TOR-S6K protein pathways and the PKA sugar pathway.
  • The demonstration of the role of proteins in aging and disease, but only in the 65 and below population.
  • The importance to focus on youth and not aging, which I call juventology.
  • The importance to base nutritional recommendations on the five pillars of longevity, which include epidemiology, basic research on longevity, clinical studies, centenarian studies, and studies of complex systems (cars and planes).


2. What’s the biggest mistake you see people make in terms of eating?

[People] demonize a certain food component such as fats or carbs, not understanding that the devil is in the details. It’s not about choosing one or the other, but which kind and how much of it. [People] also think that to be healthier you need to eat less, when in fact you need to eat more, but mostly vegetables and legumes.


3. You recommend two meals and one snack a day for most people. Can you tell us why?

Because it makes it easy to regulate food intake for people that tend to overeat. You just have to follow a simple rule and for the great majority of people it will work.


4. Fasting was a regular part of life in the original blue zones regions due to religious observances. Fasting and intermittent fasting has been quite a trend recently in the health world. In your new book, you recommend the Fasting-Mimicking Diet, which is based on your research. Can you briefly outline how it is different from the other fasts that are out there?

It is very different since it lasts for five days and it does not require to [completely] fast, since it allows foods that most people can handle. Intermittent fasting is a confusing word that we should stop using since it is similar to saying intermittent eating. Naturally we don’t eat all of the time and we don’t fast all of the time so it means nothing. We need to use words like “time restricted feeding” or “alternate day fasting,” which are very different from each other but let you know what they refer to. The five day Fasting-Mimicking Diet is not intermittent fasting since it is part of what I call “periodic fasting.”

[Editor’s Note: The FMD program created by Dr. Longo includes eating 1,100 plant-based calories (nuts, vegetables, soups, olives, tea) on the first day and then around 800 the next four days for five days overall. Prolon, a company Dr. Longo helped found but from which he receives no financial benefit, has created a line of soups, bars, and teas for people to eat on the fast-mimicking diet. Coffee is allowed but strenuous exercise and alcohol are not. ]


5. In your studies, are there immediate benefits for doing the Fasting-Mimicking Diet once? We assume most of the benefits come if it’s done in cycles — a few times per year.

There are some benefits, but they are not as strong as those you see after three cycles.


6. Your new book is called The Longevity Diet; what are the things that you want people to eat more of and less of to slow aging and fight disease?

[I recommend] more vegetables and legumes, more foods containing vitamins and minerals and essential fatty acids, less animal foods, with the exception of low-mercury foods, and low, but sufficient, proteins.


7. For people who want to move away from animal protein and start eating more plant-based foods, what are a few easy ways they can start to transition?

Find legumes that you like including garbanzo beans, black beans, etc. However, [some] fish consumption makes life a lot easier.


8. What does your diet look like? Do you eat the same thing every day for breakfast — or do you like a variety?

I eat the diet I described above for my overall diet; for breakfast, I always have one green tea and one black tea bag with a squeeze of lemon, and cinnamon raisin toast with a low-sugar fruit preserve.


9. What do you think is the most important non-food-related thing people can do to improve their health?


[Related: What is the Best Exercise for Longevity?]

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