Medieval dietetics

Translator: Bruce Lee

Dietetics is fashionable nowadays. Healthy eating habits, meant to keep one healthy, have become the leitmotiv of women’s magazines. The French government has launched a national healthy eating program and communication campaigns which recommend one to have some physical activity, to eat 5 portions of fruit and veg a day and to limit one’s consumption of salt, sugar and fat.

It has been forgotten that the interest for healthy eating was born in ancient Greece. Hippocrates, Galen and their medieval successors made similar recommendations: having physical exercise, eating food that is adapted to one’s temperament and to the time of year. In ancient times it was believed that illness was born from a lack of balance between 4 humours, and that dietetics was one of the 3 pillars of medicine (along with medication and surgery). In modern times it is all about unbalanced diets and nutrition troubles.

We say that food is made of carbohydrates, lipids and proteins, that it includes mono-insaturated fats or polyphenols. In ancient times they said: melon is cold and dry, and veal is hot and moist. Yet we still say a person is choleric or phlegmatic, in good or bad temper. Are we so far away from ancient theories of humours and temperaments?

  1. What is dietetics?
  2. The origins of medieval medical knowledge
  3. Medieval dietetics.

1 - What is dietetics?

This word comes from the Latin adjective diaeteticus relating to a diet, and the noun diaetetica set of rules to have a balanced diet. These Latin words themselves stem from the Greek diaitetikos, coming from diaitan submit to a diet.

In the Middle Ages the word dieta (same origin) means the reasoned use of the diet; a food diet. Medieval therapy includes 3 fields: surgery, pharmacy and diet (or regimen, both words are used indifferently). Prevention or healing with food is therefore an important aspect of medicine. A diet only became a synonym for depriving oneself of food on medical prescription from the 16th century. This word used to have a very broad meaning in the Middle Ages, and later its meaning became more restricted.

Dietetics today means the study of eating habits; the systematic study of nutrition (rations, calories).

If words like gastronomy and greed are linked to the pleasurable aspect of eating, the words dietetics and diet were connected, originally, to notions such as reason, reflection, analysis, all applied to eating. The word diététique is used in French from the 16th century onwards. Between that time and the 11th century at least, medieval texts in Latin usually spoke of regimen of health (regimen sanitatis) when they were meant to make medicine accessible to the vulgum pecuus. Specialised medical texts described which diets were adapted to which diseases in volumes called Consilia (consultations) when they were meant for medical scholars or physicians, according to Marilyn Nicoud, a historian who studies medieval treaties on dietetics.

It can therefore be said that dietetics or regimen of health define a controlled way of eating in order to preserve one’s health, as opposed to impulsive eating which does not care about consequences. Actually there was originally no contradiction between gastronomy and dietetics: controlling one’s way of eating does not mean eating badly or deprive oneself of food. It is a healthy lifestyle applied to food. It means eating moderately and wisely.

Top of page


2 - The origins of medieval medical knowledge

The main source of medieval dietetics was the famous School of Salerno (located in Italy, south of Naples) and its major book written around 1060: Flos medicinæ vel regimen sanitatis Salernitanum (Medicine according to the Salernitan regimen of health). This medieval text includes, in particular, rules of hygiene and eating to keep healthy.

There is said to have been 4 founders to the medieval School of Salerno: a Latin, a Greek, an Arab and a Jew. This origin, even if it is legendary, sums up the origins of medical knowledge at the time: Greek medicine (embodied by the Latin and the Greek) and Arabic medicine (embodied by the Arab and the Jew).

Greek dietetics

Eistein rightly said: It is the theory which determines what can be observed. This is true for the origins of dietetics in ancient Greece: Greek dietetics was born of the meeting between the physicians’ observations and pre-Socratic philosophy. The first Greek philosophers, between the 6th and 4th centuries BC, wondered about the origin of things. What are all things made of? Water, said Thales (late 7th-early 6th centuries BC); Air, said Anaximenes (~-550/-480), Fire, said Heraclites (~-576/-480), Earth said Xenophanes (~6th century BC). Pythagoricians like the physician Alcmeones (~-520/-450) and the philosopher and physician Empedocles (~-490/-435) later made a synthesis of those theories and used as the 4 roots of things; Water, Air, Earth and Fire. They developed the idea of a system of binary oppositions in the universe: hot/cold, dry/moist, bitter/sweet. Health comes from the balance between those principles, and maintaining this balance is the way to keep healthy. Unbalance or the predominance of one principle leads to illness and then to death.

Alcmeones, before Hippocrates, underlined the importance of the diet, the lifestyle, the environment and the weather to understand and prevent illness. Later the theory of humours was developed in the Hippocratic Collection treaties (between 430 and 380 BC) and chiefly by Hippocrates’s son-in-law, Polybes, in his treaty On the nature of man.

At the same time India saw the development of Ayurveda (science of life in Sanskrit): a way of life, a philosophy or a medicine, developing a theory with 5 great elements (Ether or Vacuum, Air or Wind, Water, Fire, Earth). 3 of them (Wind, Fire and Water) give life and motion to the body. The Wind (Vata or vâyu) comes as breath (prâna), the Fire (Pitta) as bile; Water (Kapha or çlesman) as phlegm. Those 3 elements are also called humours (doshas). When elements and humours are balanced, the person is in a state of health (tridhâtu). Illness comes from the lack of balance (tridosa: the 3 troubles).

In addition to some similarities between Greek medicine and Indian medicine in the theory of humours, Indian theories are particularly mentioned in the Treaty of Winds by Hippocrates and the Timaeus by Plato.

Were the Greeks influenced by Ayurvedic theories or did they influence them? Trade between India and the West has existed for a very long time. Seals of the Indus civilisation (2400-1750 BC) were found in Mesopotamia. Later, after the conquest of the Indus by Dairus I (522-486 BC), whose Persian Achaemenid empire stretched from the Indus to the region of Thrace, these territories were occupied for 185 years. Persian civil servants created an arameo-indian writing to adapt to Indian languages. Jean Filliozat, a specialist of the origins of Indian and Greek medicines, thinks that the theory of humours already existed in an embryonic form in the Atharvaveda (late 2nd millennium) and that there are strong connections and similarities between Indian and Greek theories. There would have been no direct contact between Indian doctors and Greek doctors, no direct borrowing from texts, but indirect contacts through the Persians (Darius had Greek physicians). As a proof for his hypothesis, this doctor mentions 2 Indian remedies based on pepper and cinnamon which are referred to in the Hippocratic treaty On the Female Diseases. Those two spices are mentioned, in Greek, under their Persian name, which stems itself from Sanskrit.

Greek physicians transcribe their theories in the written form before Ayurvedic physicians, whose texts, attributed to Caraka and Suçruta are only known in the first centuries AD. But it is very likely that they were influenced, through Persia, by Ayurvedic theories, which are older than the Greek medical theories of pre-Socratic times.

Hippocrates of Kos (~460/360 BC) has become a symbolic figure of medicine, so much so that the Hippocratic oath is still a reference nowadays as far as medical ethics are concerned. Hippocrates is considered an excellent clinician, who transcribed scientific observations and differentiated medicine from magic and religion. His theories may nowadays seem obsolete, but some of his clinical descriptions still remain valid.

He probably wrote himself The Regimen of Acute Diseases which provides eating advice for people suffering from acute diseases:

Many things connected to the previous ones could still be said about digestion, to show that the body copes well with foods it is used to, even they are not of a good nature; similarly with drinks; and that it does not cope well with foods it is not used to, even if they are not bad, and similarly with drinks.

The famous treaty On Regimen on the other hand, dealing with the diet one should follow to keep healthy, is probably the work of a disciple of Hippocrates at the time. This treaty, which provides advice on eating habits, sexual habits, bathing, physical exercise, according to the age, the place of living and the time of year, became a reference in the Western world.

I shall first write to help the vast majority of people who eat and drink haphazardly, have to work and move, toil to get a decent living, are exposed to the sun and the cold against useful purposes and have, on top of all, irregular eating habits. This is, for these people, the way to live according to circumstances. (III, LXVII, 1).

Garlic is hot, laxative and diuretic, good for the body, bad for the eyes, for if the body is compelled to great purging, the sight becomes weaker. It is laxative and diuretic because of its purgative character. It is weaker boiled than raw. (II; LIV, 1).

Hippocrates, On Regimen

Hippocratic physicians identify 4 fluids or humours: blood, which is hot and moist, yellow bile, which is hot and dry, phlegm, which is cold and moist, and black bile (melancholy), which is cold and dry. The existence of the latter is questioned by modern medicine. Drawing on Alceones’s ideas, health is seen as the right balance between humours. It is therefore necessary to have a lifestyle and eating habits that enable one to maintain this balance or to compensate the unbalanced aspects linked to the time of year or the person’s age.

Hippocrates’s successors developed the theory of Hippocratic temperaments: choleric or bilious, sanguine, phlegmatic or lymphatic, melancholic or atrabilary.

Oldcook: Medieval dietetics - Hippocrates, Galen, Avicenna

Galen, Avicenna, Hippocrates

It was then forgotten that the basis of the Hippocratic system was the clinical observation of the patient. Following Socrates, Plato and then Aristotle, one of the idiosyncrasies of Western thought emerged: putting the theory, the mere idea, before the praxis, concrete observation. Galen (~131 - 201 or 210), Greek physician of the Roman emperor Marcus Aurelius, intended to complete Hippocrates’s work. He reused and developed the theory of humours, adding graduations and combinations that were later reused and refined to the utmost degree by Arab and Latin physicians. Galen classified foods and medications on a 4 degrees scale. For example, pepper is hot in the 4th degree, garlic is dry and hot in the 4th degree. Galen created a beautiful coherent system, but he was more interested in the symmetry's pleasure of this system than in the scientific observation of facts.

His system of thought was so enticing to the Western mind, more interested in speculation than in reality, that it only began to be criticised in the 16th century and completely abandoned only when modern physics and chemistry appeared in the 19th century. In psychology, this system survived until the 20th century in Le Senne’s (1882-1954) characterology.

Arabic medicine

When the Christian religion became the state religion in the Mediterranean world, the secular heritage of Hippocrates and Galen was partly forgotten. Physicians found themselves in concurrence with healing saints. The epistle by James says:

Is there any one sick among you? Let him call the Church vicars so that they pray for him after anointing him with oil in the name of the Lord. The prayer of the faith will save the patient and the Lord will raise him again. (4, 13-15).

The ancient medical tradition chiefly survived in the Byzantine empire. Then the theological quarrels of the 4th and 5th centuries Christian Church favoured the exile of many educated people expelled from Constantinople. They ended up in Syria and Persia, taking with them ancient culture and manuscripts. The Baghdad caliphs (Al-MAnsur, 754-775, in particular) of the Abbasids dynasty, seduced by ancient culture, attracted intellectuals into the House of Wisdom (Bait al-hikma) where they created a library closely similar to that of Alexandria. They thus attracted to their court philosophers, geographers, translators and physicians, who studied and translated into Arabic Aristotle, Plato, Hippocrates and Galen. Harun al-Rachid’s personal physician was a Christian, Jibrail.

Between the 9th and the13th centuries, Arabic, Jewish and Persian physicians and philosophers studied ancient texts, compared it with Indian knowledge (the Abbasids’ caliphate stretched from the Indus to Spain before it was destroyed by the Mongols in 1258), developed their own research and published them, in Persia, in Baghdad or in Andalusia. Their names were Rhazes (or Rasis, ~860-923, also known as the Arabic Galen), Abulcasis (936-1013), Avicenna (980-1037), Averroes (1126-1198), Maimonides (1135-1204).

Rhazes said: As long as you can heal with food, do not heal with medication. The regimen of health is part of the therapies of Arabic medicine.

The physicians of the Arab-Muslim world use Hippocrates’s theory of humours and Galen’s classification of foods and medications by degrees for their own purposes. The knowledge of Eastern physicians was translated in to Latin by translators such as Constantinus Africanus (1015-1087) or Gerard of Cremona (1114-1187). The school of Salerno then simplified and broadcasted this knowledge into the whole Christian West with their book Medicine according to the Salernitan regimen of health (1060 Flos medicinæ vel regimen sanitatis Salernitanum).

One of the most famous books on dietetics that was transmitted to the Christian West was the Taqwim as-sihha (table of contents of health) by Ibn Butlan (a Christian physician trained in Baghdad who dies around 1068). This manuscript was translated into Latin under the name of Tacuinum sanitatis at the Sicilian court of Manfred, son of the emperor Frederic II Hohenstaufen.

The Tacuinum sanitatis begins like this:

Handbook for health relying on medical observation, detailing the six necessary things and underlining the useful characteristics of foods, drinks and clothes, as well as their drawbacks, according to the advice of the surest ancient sources.

96 fruits, vegetables and spices are studied, as well as 9 types of weather, 7 dairy products, salt, 4 breads, 29 meats (including pork), 5 fishes, 14 drinks and aromatic products and 23 human activities. This mixture of foods, weather and activities follows the Hippocratic lifestyle principles. Their nature is analysed: sweet cherries are cold in the 2nd degree and moist in the 3rd, hazelnuts are hot in the 1st degree and moist in the 2nd, cabbage is hot in the 1st degree and dry in the 2nd, the north wind is cold in the 3rd degree and dry in the 2nd, roasted meat is hot and dry while veal is hot and moist in the 1st degree, etc. It is also known that summer rooms must be cool and slightly wet, whereas winter rooms must be moderately hot.

Top of page


3 - Medieval dietetics

By Laetitia Bourgeois-Cornu, medieval historian, author of The good herbs of the Middle Ages, 1999.

The theory of the four elements is not an exclusively medieval one. The ancient Greeks invented it, and it was used in modern times too in spite of the constant discoveries that were made in the field of medicine. But this theory is inseparable from medieval thinking.

What is this theory? Like earthly bodies made of 4 elements (Air, Fire, Earth, Water), human bodies are made of 4 fluids, called humours: blood, yellow bile, black bile, phlegm (or lymph). Each of these humours brings together two of the 4 fundamental forces (qualities): heat, cold, dryness and moistness. Each of them becomes dominant during each of the four seasons and each of the four ages of life.

The quaternary system combining elements, humours and qualities is represented in this fashion:

Oldcook: Medieval dietetics - The diagram of the theory of humours and 4 elements

Theory of humours and 4 elements

The blood, which corresponds to Air, is both hot and moist. This element dominates childhood, spring, and gives a sanguine temperament, inclined towards pleasure. The yellow bile, also known as choler, hot and dry, dominates youth, summer, and gives a choleric temperament, full of Fire. Autumn, cold and dry, is the season corresponding to adult life, dominated by the Earth and its correspondent, the black bile. The adult temperament is atrabilary or melancholic – which is the Greek word for black bile. And winter is the time of Water, cold and moist, and corresponds to old age. Older people are lymphatic or phlegmatic, dominated by the phlegm (or lymph).

Each person is born with a dominant humour, which is distinctive of his character. A sanguine person is of reddish complexion, vigorous, and tends to put on weight. A choleric person has a yellow complexion, a dry and nervous body. The atrabilary person is rather thin, with a grey complexion. A lymphatic person is rather thin and limp, with a pale complexion.

Each type of character is drawn to the foods that correspond to him. The sanguine person likes meat with sauce, and wines, which are hot and moist like him. The choleric person is rather attracted to grilled meat, spices, hot and dry things. The lymphatic ones eat soup, raw vegetables, and the atrabilary ones roots coming from the Earth, their dominant element.

This natural kind of balance, or rather this slightly unbalanced distribution of humours was considered normal. In the Middle Ages there was no absolute quest for balance, which would bring a perfectly balanced character. Every person followed their temperament, like their destiny, got to know the four forces - heat, cold, dryness and moistness - with the influence of time and seasons.

But if things become too unbalanced, it leads to physical and mental disturbances, namely illness and madness. Medieval physicians therefore endeavoured to maintain some balance among humours, and had to act when one of the fluids really becomes too important. They bled and purged the patient in order to get rid of the excess of fluid. They prescribed remedies and foods corresponding to the missing humours. Health was thus restored, as well as the balance proper to each individual.

The theory of humours is a world of its own, well organised, in which every thing has a place and an explanation. There are some adjustments to be made, though. The four elements have an equal worth and are organised in circles. But they are sometimes represented on a scale: the Fire at the top, as it dominates even the sky (the limbo was supposed to be made of Fire), then comes the Air, then the Earth and then the Water. This scheme gives arguments to those who also think a hierarchy of human beings is just as natural. For example, aristocrats, whose nature is flamboyant, connected with Air, dominate earthly peasants. Which is why airy foods like birds, fruits (growing in the trees, in contact with the air) become aristocrats and not peasants, who eat vegetables growing in the earth, and fish.

This kind of global explanation is therefore easily perceived as limited, and yet the relevance of observations and the tolerance with which medieval people accepted various types of behaviour (especially in matters of food) are quite striking. Our civilisation has not prospered for two thousand years without bearing traces of the theory of humours. They can be easily traced in everyday words. When a person is described as dry or hot, when people feel melancholy or act with some phlegm, they are – unbeknownst to them - very much connected to Hippocratic medicine.


Top of page

La diététique médiévale