World-leading authority on dietary interventions speaks out on the importance of “getting it right” when it comes to fasting for longevity.

When it comes to scientific research at the intersection of fasting and longevity, there are few as qualified as Dr Valter Longo, director of the Longevity Institute at the University of Southern California and director of the Longevity and Cancer Program at the IFOM Institute in Milan, Italy. The author of international bestseller The Longevity Diet and creator of the fasting-mimicking diet was named one of the 50 most influential people in healthcare by Time Magazine in 2018 for his research using fasting to improve health and prevent disease.

Longevity.Technology: Thanks to the work conducted by Longo and others, the term “fasting” has become a hot topic in the longevity field. But, while fasting clearly has the potential to deliver longevity benefits, it’s still a practice that needs to be carefully considered and conducted with proper care and attention. With 2022 marking 30 years of Longo’s work in this field, we caught up with him to learn more about his research and, first, his views on the growing popularity of fasting.

Developing the fasting-mimicking diet took Longo and his team many years of research, but came to widespread attention following a 2015 mouse study, which showed compelling results in multi-system regeneration, enhanced cognitive performance, and healthspan.

“So now everybody’s fasting, and we don’t seem to realise that fasting is just a word,” says Longo. “It’s like eating – is eating good for you? What does that mean? It can be good for you and terrible for you. It’s the same with fasting – it depends how you do it.”

Fasting-mimicking diet benefits

Longo’s research is looking deeper into the mechanisms and data associated with fasting in order to help people make more informed decisions around the practice.

“For example, most people don’t realise, if you fast too long, your metabolism actually slows down,” he says. “And if you don’t fast long enough, you’ll never get into a ketogenic mode.

So you’ve got to get fasting right to benefit from it.”

This focus on the need to prove benefits with data is why Longo believes in the five day fasting-mimicking diet he developed over 15 years, and which is now being used by consumers and in clinical studies all over the world.

“I think the more extreme approaches, such as daily caloric restriction, are too much for most people, which is why I’m really optimistic about the fasting-mimicking diet,” he says.

“People can do this two or three times a year and then do what they need to do for the rest of the year. We’ve already had hundreds of thousands of people, tens of thousands of doctors and many clinical trials using it around the world.”

Diet, intermittent fasting and exercise

Through his work, Longo also has strong views on how published data supports other aspects of longevity, and highlights several key areas that people can start doing today to improve their healthspan – starting with a pescatarian diet.

“The data overwhelmingly shows that a pescatarian diet seems to be a good idea,” he says.

“Lots of people will say that a vegan diet is bad for you, but very few will say a pescatarian diet is bad for you.

When it comes to intermittent fasting, Longo believes the data supports 12 hours a day of fasting, but does not necessarily support the 16 hour fast that is so popular today.

“The data supports a 12 hour fast, because there are virtually no negative studies for that,” he says. “Yes, 16 hours can be effective in some cases, but there are also lots of negative studies about people skipping breakfast and fasting for 16 hours a day. So maybe it could be very good for some people, but can I really recommend it to a healthy 36 year old? Probably not.”

And what about exercise, I hear you say?
“In the meta-analysis, the data supports 150 minutes of exercise per week, which appears to make a difference to how long you’re going to live,” says Longo. “If you go up to 300 minutes a week, you can maybe do a little bit better, but not very much. It seems like 150 minutes exercise, with some of it being strenuous, is all you need, according to the data.”

Decisions lead to healthy longevity

However, despite all the useful data allowing us to make good decisions, Longo isn’t optimistic that humanity is on a path to health longevity.

“I would say that the vast majority of people are not on a path to healthy longevity,” he says.

“Obesity has been rising steadily in the last seven years, supported by the food industry and a medical industry that thinks if you’re sick, you’re a client.”

Longo sees a separation in society, at least in Europe and North America, into two groups of people, and not necessarily along financial lines.

“I think it’s more about the decisions you make,” he says. “There’s going to be one group that is going to believe the science, and the people that have dedicated their lives to this, and try to get a good common denominator out of that. That’s going to be a minority of the world population, but it could be half a billion people.”

“And then you’re going to have the other seven billion people that improvise, have Western diets, don’t exercise, become obese or overweight, and have inflammatory disease. That group is going to have a problem – they’re going to live shorter and be kept alive by lots of drugs, and lots of doctors and lots of money.”

But Longo is convinced that we can “revolutionise things” and that other developments in the longevity field can play a key role in this.

“In terms of drugs, we need to see what’s going to happen with things like rapamycin, Metformin, sirtuins and spermidine,” he says. “I think we’re slowly going to see some winners – some safe winners. And then we’re also going to see more doctors trained in this healthspan world. You’re going to see dietitians and nutritionists not sending you home with a new diet, but following you for the rest of your life to make sure you make it to 110 healthy.”

Read more about using fasting to lose weight and improve health and lifespan HERE.