Medieval monks gave up meat for centuries but almost never gave up fish
The word pescetarian was only coined in late-1980s Britain, blending Italian pesce with vegetarian. The habit is far older. Benedictine monks banned four-legged meat yet ate fish routinely, Japan's emperors approved seafood in 737, and even Pythagoras, patron of the meatless diet, may have eaten fish now and then.
Religious rules shaped the diet more than taste did. The Rule of Saint Benedict forbade the flesh of four-footed animals except for the sick, so monks lived on vegetables, dairy, eggs and fish; one Benedictine, Walafrid Strabo, summed up his menu as salt, bread, leeks, fish and wine. Carthusians ate fish, cheese, eggs and vegetables, dropping to bread and water on Fridays, and thirteenth-century Cistercians dug ponds to farm fish. Some sects saw fish as purer: the Manichaeans believed creatures born in water without mating escaped the taint that stained land animals.
Japan followed its own path. In 675 Emperor Tenmu banned eating livestock and most wild animals, influenced by Buddhism and scarce farmland, and in 737 Emperor Shomu allowed fish and shellfish. For roughly 1,200 years afterwards, until the Meiji Restoration, meals were largely vegetarian with seafood saved for special occasions. In Victorian England, Francis William Newman, who led the Vegetarian Society from 1873 to 1883, opened associate membership to fish-eaters and in the 1890s became one himself, reasoning that fish breed abundantly, need no land and have no parental feelings to offend.
Today the diet is small but steady. Ipsos MORI found in 2018 that about 3 per cent of people worldwide were pescetarian, the same as vegans, and it is more popular among women than men wherever data exist. Environmental arguments are strong: a 2014 lifecycle study estimated a 45 per cent cut in greenhouse emissions compared with eating everything, and a multinational study suggested a balanced version could shrink a diet's water footprint by 33 to 55 per cent.
The ethics are less tidy. Some people choose fish believing they feel less fear and pain than mammals, but fish brains have regions that can process pain, and their pain receptors resemble ours. Mercury and PCBs are a known concern in some species, though low-mercury choices exist. Among Seventh-day Adventists, around 10 per cent of those surveyed in North America in the 2000s ate this way, avoiding shellfish in line with Leviticus 11.
Source: Pescetarianism
