What is the Pythagorean diet? Exploring the ancient vegetarian philosophy

January 2, 2026 •

4 min read

Did you know that until the 18th century, the practice of a meat-free diet was commonly known as the "Pythagorean diet"? This dietary tradition, rooted in the teachings of the ancient Greek mathematician and philosopher Pythagoras, is far more than a simple food regimen; it is a holistic lifestyle driven by deep-seated ethical and spiritual convictions.

Quick Summary

An exploration of the Pythagorean diet, an ancient form of vegetarianism guided by philosophical tenets of reincarnation and spiritual purity. It emphasizes unprocessed plant-based foods while prohibiting meat and other items.

Key Points

Ethical Foundation: The diet was based on the belief in the transmigration of souls, leading Pythagoreans to abstain from eating any animal flesh.
Spiritual Purity: Adherence to the diet was intended to promote spiritual and moral purity, as well as foster mental clarity.
Plant-Based Focus: The core of the diet consisted of whole, unprocessed plant foods, including fruits, vegetables, grains, and nuts.
Unique Taboos: A notable feature was the strict prohibition on eating fava beans for mysterious reasons related to purity and the afterlife.
Inspiration for Modern Movements: The Pythagorean diet is a historic precursor to modern vegetarian and vegan philosophies, influencing centuries of ethical eating.
Resembles Lacto-Ovo Vegetarianism: While primarily plant-based, the diet allowed for minimal amounts of dairy and eggs, making it similar to a modern lacto-ovo vegetarian diet.

The Philosophical and Ethical Foundations

At its core, the Pythagorean diet was inseparable from the broader philosophical movement known as Pythagoreanism, founded in the 6th century BCE. While most people associate Pythagoras with his geometric theorem, his school of thought also emphasized ethical living, asceticism, and a belief in the transmigration of souls, or metempsychosis.

The Transmigration of Souls and Non-Violence

The central impetus for abstaining from meat was the belief that the soul is immortal and is reborn into various living beings, including animals. Consuming animal flesh was therefore viewed as an act of violence against a fellow creature that might harbor a human soul. As a result, Pythagoreans practiced a form of non-violence (ahimsa), extending compassion and respect to all life. This ethical stance was radical for its time, challenging the prevalent Greek practice of animal sacrifice.

Simplicity and Spiritual Purity

Beyond ethics, the diet was a tool for achieving spiritual purity and mental clarity. Pythagoreans believed that a simple, balanced diet of unprocessed foods would nourish the body and soul, avoiding the "pollution" that meat-eating was thought to cause. This emphasis on moderation and balance was a key tenet of their lifestyle, extending beyond just food to encompass all aspects of life.

What to Eat and What to Avoid

Pythagoras and his followers primarily subsisted on a plant-based regimen. While the specifics are debated, historical accounts suggest a diet based on fruits, vegetables, grains, and nuts.

A List of Acceptable Foods

Fruits: Fresh and dried fruits were a staple part of the diet.
Vegetables: A wide variety of vegetables were consumed, with special emphasis on fresh and raw options.
Grains: Whole grains like barley and wheat were used to make bread.
Nuts and Seeds: Rich in nutrients, these were included regularly.
Legumes: Most legumes were acceptable, except for one notable exception.
Dairy and Eggs: Minimal amounts of dairy and occasional eggs were consumed, making it similar to a modern lacto-ovo vegetarian diet.
Honey: This was considered an acceptable food of animal origin.

The Curious Prohibition of Fava Beans

One of the most peculiar restrictions of the Pythagorean diet was the complete taboo on fava beans. The reasons for this ban were multi-faceted and mysterious, with different accounts suggesting different origins:

Reincarnation: The beans were sometimes seen as resembling a human fetus or a gateway for souls from the underworld, making their consumption akin to cannibalism.
Health: Some suggest it was for health reasons, possibly due to the risk of favism (hemolytic anemia) in those with G6PD enzyme deficiency, which was a known risk in the Mediterranean region.
Mystical Significance: The ban may have simply been a test of obedience or a marker of their unique, ascetic lifestyle.

Pythagorean Diet vs. Modern Diets

Although the philosophical roots differ, the food choices of the Pythagorean diet share similarities with modern plant-based diets, though some key distinctions exist.


Feature	Pythagorean Diet (Ancient)	Modern Lacto-Ovo Vegetarian	Modern Vegan Diet
Meat and Fish	Excluded	Excluded	Excluded
Dairy Products	Minimal use	Consumed	Excluded
Eggs	Occasional use	Consumed	Excluded
Honey	Allowed	Often consumed	Excluded
Fava Beans	Prohibited	Often consumed	Often consumed
Processed Foods	Avoided	Generally a preference	Often a preference
Motivation	Ethical, spiritual purity, reincarnation	Ethical, environmental, health, personal	Ethical, environmental, health, personal

Modern Takeaways and Relevance Today

Despite its ancient origins, the core principles of the Pythagorean diet resonate with many modern approaches to healthy eating. The emphasis on whole, unprocessed, and plant-based foods is linked to numerous health benefits today, including a reduced risk of chronic diseases like heart disease.

However, potential nutritional deficiencies must be managed, particularly for individuals fully committing to such a restrictive regimen. Key nutrients like vitamin B12 (found mainly in animal products), iron, and omega-3 fatty acids require careful planning.

Today, the Pythagorean diet serves as a powerful historical precedent for vegetarianism and conscious eating. It reminds us that dietary choices can be a reflection of our deepest philosophical and ethical values, connecting the health of the body with the purity of the mind and spirit. To learn more about the profound influence of this ancient philosophy, explore the history of vegetarianism at Britannica.

In conclusion, the Pythagorean diet is not a relic of the past but a foundational pillar of ethical vegetarianism. Its legacy is found not only in the health benefits of plant-based eating but also in the enduring idea that our relationship with food is a reflection of our connection to the world around us. Its timeless message of harmony and compassion continues to inspire contemporary movements toward more conscious and sustainable living.

Frequently Asked Questions

The diet is fundamentally rooted in the Pythagorean belief in metempsychosis, or the transmigration of souls. This means they believed a human soul could be reborn into an animal, making the consumption of animal flesh an unethical act.

Pythagoreans were strictly forbidden from eating meat and fish. They also famously had a unique taboo against eating fava beans, for reasons that are not fully understood but likely related to their spiritual beliefs or health concerns.

Yes, while prohibiting meat and fish, historical sources indicate that the diet permitted minimal consumption of dairy products and occasional eggs. Honey was also an acceptable food.

The exact reason remains a mystery, with several theories existing. Some suggest it was due to the bean's association with the underworld and reincarnation, while others point to potential health risks like favism or simply the symbolic nature of the taboo.

No, it is not the same as a modern vegan diet. A vegan diet excludes all animal products, whereas the Pythagorean diet allowed for small amounts of dairy, occasional eggs, and honey. It also uniquely banned fava beans.

From a modern nutritional perspective, the diet's emphasis on whole, unprocessed plant foods, rich in fiber and vitamins, could contribute to lower cholesterol, reduced risk of heart disease, and increased energy.

For those not consuming eggs or dairy, careful attention must be paid to obtaining adequate levels of nutrients typically found in animal products. These include vitamin B12, iron, and omega-3 fatty acids, which can be supplemented or obtained from fortified foods and other plant sources.