The monks of the Koutloumousi monastery enjoy astonishingly low rates of cancer.
Their low-stress existence and simple diet (no meat, occasional fish, home-grown vegetables and fruit) may, however, also protect them from more worldly troubles.
Since 1994, the monks have been regularly tested, and only 11 have developed prostate cancer, a rate less than one quarter of the international average. In one study, their rate of lung and bladder cancer was found to be zero.
The monks' diet, which calls on them to avoid olive oil, dairy products and wine on Mondays, Wednesdays and Fridays, helped to explain the statistics. "What seems to be the key is a diet that alternates between olive oil and nonolive oil days, and plenty of plant proteins," he said. "It's not only what we call the Mediterranean diet, but also eating the old-fashioned way. Small simple meals at regular intervals are very important."
The staples are fruit and vegetables, pasta, rice and soya dishes, and bread and olives. They grow much of what they eat themselves. Agioritiko red wine is made locally from mountain grapes. Dairy products are rare – female animals are banned from the autonomous semi-state.
Life on Athos has changed little over the past 1,043 years. Breakfast is hard bread and tea. Much of the day is taken up with chores – cleaning, cooking, tending to crops – followed by a supper, typically of lentils, fruit and salad, and evening prayers.
Father Moses of the Koutloumousi monastery, one of the 20 organised cloisters scattered over the Athos peninsula, said: "We never eat meat. We produce most of the vegetables and fruit we consume. And we never forget that all year round, on Mondays, Wednesdays and Fridays, we don't use olive oil on our food."
The olive-oil routine, which also applies to wine and dairy products, appears to have no religious significance, but is a way of eking out their supplies.
All the monks stick to the rigorous fasting periods of the Orthodox Church, in which a strict vegan diet is prescribed for weeks at a stretch.
Michalis Hourdakis, a dietician associated with Athens University, said: "This limited consumption of calories has been found to lengthen life. Meat has been associated with intestinal cancer, while fruit and vegetables help ward off prostate cancer."
The lack of air pollution on Mount Athos as well as the monks' hard work in the fields also played their part, the researchers said. There was no mention, however, of whether the absence of women had any effect on the monks' renowned spiritual calm.
That is the inescapable conclusion from research into one of the world's most renowned monastic communities.