Valter Longo grew up in a village in Calabria called Molochio, famous for being a so-called ‘blue zone’ – an area where the locals were known to live exceptionally long lives and to suffer lower rates of chronic disease.

In recent years, the town’s abundance of centenarians has become a curiosity for the likes National Geographic – and what has emerged is a story of people who eating mainly beans and fruit, and no red meat.

And, in frequent harder times, they barely ate at all.

Perhaps it was all those ancient people that freaked young Valter Longo out. As a teenager he fled to the US, where he lived with extended family and planned on being a rock star.

But he eventually abandoned his guitar and took up studying those old home-town people and asking why they have managed to live longer and healthier lives than most – and along the way he’s become a rock star in the somewhat controversial field of slowing down ageing.

A paper he wrote in 1994 that detailed the ageing pathway of yeast was rejected and even mocked for seven years. It was eventually published in 2001.

As an enthusiastic 2017 profile in Stat News reported, the paper has since been cited hundreds of times.

“If someone said, ‘What are you working on?’ we would say oxidative chemistry,” Dr Longo told Stat. “You couldn’t say ageing. That was viewed as a joke.”

Diet might work better than a cancer cure

Some theorists, such as the British molecular biologist Aubrey de Grey, believe ageing is a disease that can be cured. Once that’s achieved we could live to 1000 years, is de Grey’s contentious claim.

Dr Longo – professor of gerontology and the biological sciences at the USC Davis School of Gerontology and director of the USC Longevity Institute – is more modest in his ambitions. He’s has become convinced that diet is the key to living vigorously to the age of 110.

Professor Valter Longo on the fast-track to longevity. Photo: USC

By way of contrast, he pointed out in his 2016 Ted Talk that if we could completely cure cancer, the gains in longevity would be relatively modest, maybe an extra four or five years on average.

Where Aubrey de Grey is something of a superstar in the immortality sphere, his ideas have been written off by many serious scientists.

Professor Longo, on the other hand, has convinced many of his colleagues that he’s truly on to something. Even sceptics have suggested his ideas are plausible, but want to see larger studies in humans.

The Longo plan

In April, Professor Longo – having been in the pursuit of longevity for 30 years – co-authored a widely reported article with Dr Rozalyn Anderson, director of the metabolism of ageing program at the University of Wisconsin school of medicine and public health.

The researchers reviewed hundreds of studies on nutrition, diseases and longevity in laboratory animals and humans and combined them with their own studies on nutrients and ageing.

The net result was “a clearer picture of the best diet for a longer, healthier life”.

“We explored the link between nutrients, fasting, genes and longevity in short-lived species, and connected these links to clinical and epidemiological studies in primates and humans – including centenarians,” Professor Longo said.

Eating well might save your marbles, and even your teeth. Photo: Getty

“By adopting an approach based on over a century of research, we can begin to define a longevity diet that represents a solid foundation for nutritional recommendations and for future research.”

The short version: “Lots of legumes, whole grains, and vegetables; some fish; no red meat or processed meat and very low white meat; low sugar and refined grains; good levels of nuts and olive oil, and some dark chocolate.”

In fact, this is essentially the diet that Professor Longo previously published in book form – but now the science is catching up.

On the face of it, it doesn’t appear to be that ground-breaking.

But the innovation isn’t in the foods you consume most of the time under the plan, the life-extending potential is in what’s called a fasting-mimicking diet.

It’s a rather neat trick, where the body goes into fasting mode for five days – which prompts stem cells to regenerate the immune system – while you actually continue to eat a modest number of calories.

The Longo plan includes eating 1100 plant-based calories made up of nuts, vegetables, soups, olive and teas on the first day – and then around 800 for the next four days.

Does it actually work?

In 2017, Professor Longo and colleagues published a randomised Phase II clinical trial involving 71 healthy people aged 20 to 70.

On and off, for three months, the participants followed a periodic, five-day fasting diet designed by Longo.

The diet reduced cardiovascular risk factors including blood pressure, signs of inflammation (measured by C-reactive protein levels), as well as fasting glucose and reduced levels of IGF-1, a hormone that affects metabolism.

It also shrank waistlines and resulted in weight loss, both in total body fat and trunk fat, but not in muscle mass.

Overall, the diet reduced the study participants’ risks for cancer, diabetes, heart disease and other age-related diseases.

These positive results were found to be sustained three months after the trial.

What happens next? A large, FDA phase III clinical trial to test the fast-mimicking diet on patients diagnosed with age-related diseases or at high risk for them.

Professor Longo might be a very old man by the time he fully cracks the code for the longevity. By then, he’ll be walking proof of his own theories. Or not.

For more on Professor Longo and fast-mimicking might slow ageing, see here.