Rome, the city where civilisation was born, where the past is its present and its future and where the people who live here tear their hair out with the frustration of living a city of ruins. Ok, that’s harsh, but after five days of working with some of the best cooks and chefs in the city and with Gustolab, the only food studies institute in Italy to host scores of international students, mostly from American universities, the reality of life in Rome is a story which isn’t on the tourist trail.

A Roman Holiday is about the legacy of the Roman Empire rather than the bad tempered cabbies and the plumbers who don’t turn up on time. It’s not about the mass unemployment or the misogyny, it’s about the food. For most tourists, it’s the sublime slices of pizza or fresh pasta with truffle oil, or for the foodies, the trip to Eataly or Volpetti for the real taste of Italy.

For Gustolab’s food students, it’s the story of the Mediterranean Diet, the diet that never changes, that’s as good today as it ever was, the diet that Nonna made. It’s the UNESCO stamped example of intangible cultural heritage that if only people would eat, the world would be better, faster, stronger.  But it’s the harder bit that’s often left out of the story, although not at Gustolab. Italy, particularly southern Italy has one of the fastest growing obesity rates among its children in the world. Yet the south is where the Mediterranean Diet was crowned king.  My very first book ‘The Mediterranean Health Diet’ (with Rowena Goldman, Headline, 1993) followed a series we made for Channel Four’s ‘Food File’, the first prime-time TV show to discuss the politics of food. Among our consultants were Geoffrey Canon, co-author with Caroline Walker of ‘Food Scandal: What’s Wrong with the British Diet and How to Put it Right’ (Ebury Press, 1985) and Tim Lang who would go on to advise Jamie Oliver and become Professor of Food Policy at City University London’s Centre for Food Policy. When the British Government decided that the Mediterranean Diet would save the NHS from buckling under the weight of rising obesity rates back in 1992, Rowena and I headed for Acciaroli in Campania, and the village that the experts had concluded was the healthiest in the world.

It was simple; the people who lived on this hilltop village pressed their own olive oil, made their own red wine and ate the fit chickens which had spent their happy lives running up and down the hillside. Olive farming was better for the physique than any yoga class, and long tables set for the community of 300 were the stuff of Jamie Oliver’s dreams. Cooking from scratch ingredients that you grew yourself and ate together, preferably under a balmy evening sky, has been proved again and again to stave off everything from Alzheimers to… well, death – at least from heart disease and most cancers.

Twenty three years on, Campania is still on the Gustolab students’ itinerary. Apparently Cilento, the national park which is basking in the glory of the successful storytelling around The Mediterranean Diet has changed since the days when we were there, and as I sit writing in Rome pondering whether to hop on a train down to see what has happened to its fortunes and its rising levels of obesity, I Google instead and find that the mythologising is still in full flow; The Italian town where residents live to 100 – and scientists want to know why says the Independent in March this year. Could a HERB be the secret to living to 100? Diet rich in rosemary linked to good health and long life expectancy in Italian village  asks the Mail, using the same press release.  If you want to live forever, move to this Italian town says the New York Post.

Più cambia, tanto più è la stessa cosa as they might say in Rome. But while the Eternal City pumps the Eternal Diet as part of its cultural heritage, it’s up to people like Gustolab’s director, Dr Sonia Massari to keep it real, as far as her international students are concerned anyway. Click here to hear a brief excerpt of my interview with her this week.

Meanwhile, the Mediterranean Diet in Rome, at least, is safe in the hands of Michelin starred chef at Glass Hosterian and Romeo Chef and Baker, Cristina Bowerman. Here she sums up the diet that hasn’t changed for 3000 years, that has had more statistics and graphics thrown at it than a library of universities, and which she explains is still the best in the world.