Pythagoras forbade his followers from eating fava beans, and nobody is entirely sure why. The ancient sources give conflicting explanations, ranging from spiritual beliefs about the soul to what may have been an early observation of a genetic disease. What’s clear is that the ban was deadly serious: one famous legend claims Pythagoras himself was killed because he refused to escape through a bean field.
Beans, Souls, and the Afterlife
The most widely cited explanation ties beans to Pythagoras’s belief in metempsychosis, the idea that human souls migrate into other living things after death. Pythagoras taught that the soul was immortal and could pass from a human body into an animal, a plant, or back into another person. Under this framework, eating any living thing carried the risk of consuming a reincarnated soul.
This is why Pythagoreans avoided meat, but beans got special treatment. Ancient writers recorded the saying that eating beans “is as much as to eat your parents’ heads,” a line attributed both to Pythagorean sacred texts and to Orphic poetry. The fava bean’s hollow stem was thought to provide a direct channel between the earth and the underworld, making it a kind of passageway for souls. Some ancient accounts claimed that if you buried a fava bean in moist soil and dug it up after a set number of days, it would resemble a human head or a fetus. Whether or not anyone actually tried this, the imagery reinforced the idea that beans and human life were uncomfortably intertwined.
There were also more visceral associations. Beans were linked to human breath and bodily gases. The flatulence they caused was interpreted not as a digestive nuisance but as evidence that something animate, something with a soul’s breath, lived inside the bean.
A Religious Tradition, Not Just a Personal Quirk
Pythagoras didn’t invent the bean taboo from scratch. The prohibition appears to have roots in the Orphic mystery religion, an older spiritual tradition in ancient Greece that emphasized ritual purity and the soul’s journey after death. Orphic followers abstained from meat, eggs, and beans, and scholars have traced these dietary rules to poems attributed to the mythical poet Orpheus, dating to around the fifth century BC.
The overlap between Orphic and Pythagorean dietary laws is so extensive that ancient writers sometimes couldn’t tell them apart, labeling certain food rules as “Orphic-and-Pythagorean” without distinguishing which tradition came first. The most reasonable interpretation, according to scholars who have studied the textual evidence, is that the Pythagorean brotherhood adopted the Orphic lifestyle, including its dietary taboos. Pythagoras gave these practices a philosophical framework built around mathematics and the harmony of the cosmos, but the raw material, the avoidance of beans, was likely inherited from an existing religious tradition.
Beans as Political Tools
A more pragmatic theory connects the ban to Greek democracy. In several ancient Greek cities, citizens voted by dropping beans into containers. White beans counted as a yes vote, black beans as a no. Some historians have suggested that Pythagoras, who ran a secretive, hierarchical community in southern Italy, opposed democratic participation and used “abstain from beans” as a coded instruction to stay out of politics.
This interpretation is clever but probably too clever. The ancient sources that discuss the bean taboo overwhelmingly frame it in dietary and spiritual terms, not political ones. And while the Pythagorean community did have political influence in the Greek colonies of southern Italy, the bean-as-ballot theory reads like a later rationalization by writers who found the literal food prohibition hard to take seriously.
A Medical Explanation That Actually Holds Up
The most intriguing modern theory is medical. Fava beans can trigger a condition called favism in people who carry a specific genetic trait: a deficiency in an enzyme that protects red blood cells from oxidative damage. When someone with this deficiency eats fava beans, especially fresh ones, their red blood cells can rupture, causing severe anemia and, in serious cases, death.
This genetic trait is concentrated in exactly the regions where Pythagoras lived and worked. It is particularly common in Greece, southern Italy, Sardinia, Cyprus, and among Sephardic Jewish communities. Pythagoras spent his career in Croton, a Greek colony in what is now southern Italy, precisely the kind of Mediterranean population where this deficiency would have been prevalent. About 20 percent of people who carry the gene will actually experience episodes of favism after eating fava beans, which means in any community, a visible minority of people would become seriously ill from a food everyone else tolerated fine.
Pythagoras wouldn’t have understood the genetics, but he could easily have observed that beans made some people dangerously sick. A blanket prohibition would have been the simplest protective measure available. Ironically, both the gene and the cultural practice of eating fava beans appear to be evolutionary adaptations that protect against malaria. Favism is essentially a negative side effect of two otherwise beneficial traits colliding in the same population.
Why There’s No Single Answer
Pythagoras left no writings. Everything we know about his teachings comes through later followers and ancient commentators, some writing centuries after his death. These sources often contradicted each other, and many had their own agendas, either defending Pythagoras as a divine sage or mocking him as a superstitious eccentric. The bean prohibition became a favorite anecdote precisely because it sounded absurd to later audiences, which means the explanations we have may say as much about the writers as about Pythagoras himself.
The truth likely involves some combination of inherited religious tradition, genuine spiritual conviction about the soul, and possibly real-world observation that beans harmed certain people. For Pythagoras and his followers, these wouldn’t have been separate categories. A food that could sicken or kill would have fit neatly into a worldview where beans were already spiritually suspect, reinforcing the prohibition from multiple directions at once.