University debate: "The Blue Zones prove a plant-based diet is the key to longevity." Vegan: "Five places on earth where people routinely reach 100. Okinawa, Sardinia, Ikaria, Nicoya, Loma Linda. The common thread is beans, greens, wholegrains and barely any meat. It's the strongest longevity evidence we have." Anthropologist: "What else do the five have in common?" Vegan: "Community. Purpose. Walking." Anthropologist: "Terrible paperwork. Four of the five are remote islands or hill districts with poor birth records, and the fifth is a church. When a researcher went through the data, the places with the most centenarians were the places with the worst record-keeping and the most pension fraud." Vegan: "That's a slur on old people." Anthropologist: "In 2010 Japan went looking for its registered centenarians and couldn't find 230,000 of them. Some had been dead for decades with the family collecting the pension. Greece found about 9,000 pensioners over 100 who turned out to be in the cemetery. Okinawa's records were destroyed in the war and rewritten from memory." Vegan: "Even so, the diet in those places..." Anthropologist: "Say what it was." Vegan: "Sweet potato, in Okinawa." Anthropologist: "And pork. Every part of the pig, cooked in lard, the highest pork intake in Japan. The Okinawan word for a feast means 'pig'. Sardinia?" Vegan: "Beans and bread." Anthropologist: "Sheep. The Sardinian shepherds you're quoting live on pecorino, lamb and a glass of red. Ikaria is goat and goat's milk. Nicoya eats more eggs and pork than the rest of Costa Rica. Loma Linda is the one true vegetarian zone, and they also don't smoke, drink or divorce. Take the meat out of the other four and the sum doesn't move." Vegan: "The man who wrote the book spent years there." Anthropologist: "He sells the book. The researcher who checked the records got an Ig Nobel prize for it, which is what science gives you for pointing out the emperor's birth certificate is missing." Vegan: "So you're saying nobody there is old." Anthropologist: "I'm saying the oldest-looking data on earth tends to be in the places where nobody can check it, and when you do check, the diet turns out to be pig." Vegan: "Then what's the real Blue Zone?" Anthropologist: "Hong Kong. Longest life expectancy on the planet, immaculate records, and the highest meat consumption in Asia. It's not in the book because you can't sell beans with it." Moderator: "Time." Vegan: "I've been to Okinawa." Anthropologist: "What did they serve you?" Vegan: "..." Anthropologist: "It's all right. Everyone says pork eventually."

One of the founders of the Mayo Foundation ran a sanatorium for sixteen years in which he treated heart failure, kidney disease, high blood pressure, tuberculosis and obesity with one medicine: raw milk, several quarts a day, and nothing else. J. E. Crewe was not a crank. He was a physician at the most famous clinic in America, and the milk cure was an old treatment he had decided to take seriously. The patient went to bed. Every half hour through the day a glass of raw milk from grass-fed cows went down, up to four or five quarts, sometimes more. No other food. Weeks of it. He wrote it up in 1929 and the detail that stands out is the one that puzzled him most. He expected the swollen, waterlogged patients with failing hearts and kidneys to get worse on all that fluid. They did the opposite. The swelling went, the blood pressure fell, the urine cleared. One woman went from three hundred and twenty-five pounds to two hundred and eighty-four in a fortnight on four quarts a day, and her blood pressure came down fifty points with it. Diabetics improved. The tubercular gained weight. Nervous patients slept. Crewe said the treatment was so simple it was not interesting to the profession, and so effective it made him uncomfortable in his own clinic, because it suggested most of his colleagues' work was unnecessary. Pasteurisation came in, raw milk became a controlled substance, and the Mayo Clinic's own doctors stopped mentioning it. The article survives. The practice does not. The most prestigious hospital in America once put its sickest patients to bed with a glass of milk every half hour and watched them get well. It is now illegal to sell that milk in most of the states it was practised in.