DIET

The Cornerstone of Medicine

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Following his Hippocratic and Hellenistic predecessors, Galen regarded different foods as each possessing various properties capable of rebalancing the humors and their related elemental properties. Some foods heated while others cooled, some were moistening and others drying; there were foods that thickened the humors and others that thinned them. A poor diet could bring about illness, while the right one would preserve and even restore health. Foods were powerful in ancient medicine, and Galen wrote extensively about them.

Mosaic of fish, fowl, and vegetables in a cupboard. Roman, ca. mid–2nd century CE. Stone. Probably the floor of a triclinium, from a villa on Via Ardeatina at Tor Marancia, outside Rome. H. 122 cm; W. 122 cm; D. 6 cm. Musei Vaticani: MV.2580.0.0. Photo: Jastrow / Wikimedia. Public domain.

In his most important manual on the topic, the encyclopedic On the Powers of Food, Galen classified more than 150 different foods. He organized entries according to digestibility—pork, white meat, poultry, and fish are easier to digest than red meat, for example. But no matter the food, moderation is important: Galen warned that eating too much causes indigestion (from a buildup of the humor phlegm), but this could be remedied by drinking something hot and drying, such as wine with pepper. He described what to eat to maintain health but also what to do in the case of illness, since food is a type of medicine: when someone becomes sick, feed them barley-broth soup, and reintroduce other foods gradually as they recover. Galen’s recommendations—eat a variety of balanced foods—are quite sensible by contemporary standards, but he also held some strong opinions that are surprising to readers today. Galen was anti-fruit: he believed fresh fruit was frequently a cause of illness—except for small amounts of figs and grapes—a conclusion he drew from his personal experience as well as from witnessing the same phenomenon occur in others.

Detail of a basket of figs. Roman, 1st century CE. Fresco. Villa Poppaea, Oplontis, Italy. Photo: adriano spano / Alamy Stock Photo.

It is indeed possible that uncooked or unwashed fruit may have been a source of intestinal problems, so this position is not as scandalous as it may seem in our time. But in other cases, his food opinions are even more extreme; here he is on beef:

“Beef furnishes nourishment that is substantial and not easily digested, although it generates thicker blood than is suitable. If anyone more inclined by temperament to melancholy should eat his fill of this food, he will be overtaken by melancholy disease. These diseases are cancer, elephantiasis, scabies, leprosy, quartan fever, and whatever is detailed under the heading melancholia.”

Historians note that Galen’s interpretations of foods were informed by his medical theory, but they were also culturally conditioned—beef was typically reserved for special occasions in antiquity, and similar factors likely colored his view. 

Galen’s writings on diet and food provide fascinating insight into culinary cultures from around the ancient world. His texts include catalogues of foodstuffs common to different people from across the Roman Empire, from its capital city to rural corners of the Aegean Coast (present-day Turkey). Within his different books and treatises, Galen writes about a variety of grains and offers suggestions on cooking techniques, comparisons of different honeys, lists of wines, observations about quince tarts, and instructions on where to find wild thyme.

The cultural contexts of foods also come up with some regularity; we find descriptions of the harsh foods eaten by peasants and the sumptuous delicacies of the wealthy. Galen records the differences between rural and urban diets as well as the foods of other cultures: the rough porridges that he ate in the countryside during his youthful travels in Asia Minor caused flatulence, constipation, and headaches, and were difficult to digest; the hard skin of Egyptians revealed the effects of eating fish, snails, beans, lentils, and beer; the Scythians, on the other hand, drank milk and had virtually no skin diseases. Galen frequently draws conclusions about the healthful potential of these different foods based on his personal experience and observations, and the upshot is: you are what you eat.

Mosaic detail depicting snails in a basket. Roman, 4th century CE. Basilica Patricale, Aquileia, Italy. Photo: sailko / Wikimedia. CC BY-SA 3.0.

Diet and cultural commentary repeatedly bleed together not only in medical texts, but also in the writings of philosophers and poets. In the ancient world, eating was not simply about health: food was frequently connected with politics and ethics. Meals were often used to demonstrate wealth and power, especially by the upper classes in elaborate banquets. Indeed, when one thinks of elite Roman banquets, the hedonistic indulgence of elaborate meals with too much wine is often the image that comes to mind.

Detail of a banqueting scene. Roman, 1st century CE. Fresco. Casa dei Casti Amanti, Pompeii. Photo: WolfgangRieger / Wikimedia.

Pliny the Elder (23/24–79 CE) was critical of conspicuous consumption and attacked luxury foods, especially fancy fish, since expensive varieties commanded shockingly exorbitant prices. Yet perhaps the most familiar and cynical critique of the use of food by the ruling classes of Rome comes from Juvenal (ca. 55–127 CE), who denounced “bread and circuses.” For the average working Roman, bread was a diet staple and many city dwellers relied on grain rations from the state. The phrase evokes the corruption of the upper classes as well as contempt for their struggling fellow citizens, who often depended upon food supplements for survival.

Left: Charred loaf of bread from Modestus’s bakery. Roman, 79 CE. Carbonized bread. Pompeii. H. 6 cm; Diam. 22 cm. Museo Archeologico Nazionale di Napoli: 84595. Photo: Ministero per i Beni e le Attività Culturali e per il Turismo / Museo Archeologico Nazionale di Napoli. Right: Detail of the distribution of bread. Roman, 40–79 CE. Fresco. House of the Baker, Pompeii. H. 69 cm; W. 60 cm. Museo Archeologico Nazionale di Napoli: 9071. Photo: Marie-Lan Nguyen / Wikimedia. Public domain.

In antiquity as in the present, diets are often as strongly determined by our place in the world, geographically and socially, and by our cultural priorities, as they are by our nutritional needs.