Many written sources inform us about the Byzantine diet. The quality and variety of food was heavily dependent on the crop and livestock production of each region, as well as on family resources. The wealthy were able to satisfy their desire for rare foods imported from foreign and sometimes remote areas, whereas the poor mostly ate fruit and vegetables.Disparities in diet between social classes in Byzantium were enormous: the lower classes made do with dry food or porridge, while the aristocracy consumed a wide variety of foods at lavish lunches and dinners, though this did not necessarily mean that the various population groups went without a varied diet.

Most people apparently had two main meals a day. The first of these, called the ariston or mesembrinon, was generally taken around noon or slightly earlier. Dinner time was usually before dusk in the evening, though it could be served earlier, as the term aristodeipnon indicates, or very late at night. There are also references to additional meals, such as the prog(e)uma or the prosphagon in the morning and the deilinon in the afternoon, apparently taken by members of the upper classes, thus increasing the number of daily meals to four.

Flour, olive oil and wine, the three mainstays of the Mediterranean diet, were the staple foods in Byzantium. These were produced both in the context of family production and consumption and for trade, whether at the local level or on a larger scale.

Wheat and other cereals were cultivated as food commodities in many parts of the empire. In Late Antiquity wheat bread from Egypt was distributed free to the inhabitants of Constantinople. The quality of bread in later centuries varied according to buying power.

The best and most expensive bread was the so-called katharos artos made of finely sifted white flour, and semidalis, made of semolina, both of which were consumed by the wealthier sectors of the population. In contrast, poorer people ate an inferior kind of bread called mesokatharon or ryparon, or kyvaron, kneaded from a mix of low-quality flour. The lowest quality bread was piteraton, made of bran. Besides bread, a kind of sea biscuit known as dipyros artos or paximas was widely eaten. This could be kept for a long time, and so was the main food for soldiers on campaign and people on long voyages.

Because olives have always thrived in temperate climates they were widely known throughout the Mediterranean. Olive oil was a major ingredient of Byzantine cooking and was produced in special presses. Up until the 7^th century olive oil was transported and traded in bulk from North Africa and Palestine to Italy and the Balkans, but in later periods trade seems to have been limited to the coastal areas and islands of the Aegean. Olive oil and wine were transported and stored in amphorae, also known as magarika from mid-Byzantine times onwards.

Viniculture was so widespread that wine was produced in almost every part of the empire and was rarely absent from meals; depending on its flavour, it was classified as thick, thin, astringent (dry) or sweet. The most famous wines were those from Chios, Samos, Thassos, Pteleos in Magnesia, Crete and Ganos. The Byzantines usually drank wine warm or added hot water. Other wine-based drinks were also made, such as kyminothermoni and konditon. The former was brewed with hot water, cumin and aniseed spiced with a little pepper, whereas wine, honey and spices went into the latter.

The Byzantine staple diet also included proteins and carbohydrates. Domesticated animals were primarily bred for their dairy products and eggs, not for their meat. Consumption of either fresh or salted meat was very limited, not only because it was difficult to preserve, especially during summer, but also because the consumption of meat and dairy products was prohibited during the lengthy fasting periods. However, the fare of the wealthy included lamb, goat, hare, rabbit, poultry, game (red and roe deer, wild boar) and even frogs. Pork was well esteemed and was usually cured or boiled with vegetables. Though considered inferior, offal was used to prepare foods similar to the spit roast (kokoretsi, Byzantine plekte) and boiled (gardoumba, gardoumion) dishes eaten in Greece to this day.

Fish consumption was high, especially amongst the clergy and in monasteries. Fish and seafood were most readily available in coastal, lake and riverside areas.  Salt water fish were favoured against fish from lakes or rivers, and were usually grilled, fried or boiled, occasionally with spices and herbs. Whilst only the rich could afford to buy large and expensive white fish (mullet, bream, sea bass, sea bream and turbot), other seafood like mackerel, sardines and bonito, as well as octopus, squid, cuttlefish, mussels, crabs and the ubiquitous salt fish were eaten by all and were always on demand in the market.
 
Cheese was produced in a wide range of types, with Vlach and Cretan varieties being highly prized. Anthotyro and myzithra (soft cheeses) were widely used, whereas white asbestotyro was of a low quality intended for consumption by the poor.

Vegetables and legumes were important seasonal side dishes for the rich, also serving as main meals for the poor. During the fasts laid down by the Church they were consumed by all. Vegetables were usually grown in kitchen gardens, or bought from market traders or itinerant greengrocers. Lettuce, cabbage, spinach, onions, garlic, mushrooms, carrots, leeks, radishes, peas, beets and salad rocket were commonest, as well as herbs like dill, mint, savoury and oregano. The favourite legumes were beans, lentils, chickpeas (white and black) broad beans and lupin beans. Housewives pickled large quantities of vegetables in brine or vinegar for wintertime consumption.

The Byzantines got their carbohydrates from fruit, which was their main dessert and a daily staple for all. They consumed many varieties of apple, pears, dried and fresh figs, loquats, quinces, grapes and melons. The emperor would even hand out apples or pears to courtiers at special ceremonies to mark religious feast days. Nuts such as walnuts, almonds, hazelnuts and chestnuts played a similar role to fruit. Various kinds of sweetmeats featuring honey as the main sweetening agent served as desserts (epideipna or doulkia), such as sesame cake (sesamous), grape jelly (moustopita), quince cheese (kydonaton), honeyed walnuts (karydato), various spoon sweets and a kind of fritter (laganon or lallangi). Lastly, pastry dough, almonds, walnuts and honey went into a dessert called koptoplakous, which was probably the forerunner of baklava.

The Byzantines ate relatively simply. They mostly grilled seafood and ate raw and cooked vegetables, soups and on rare occasions meat. Though very common in the modern Mediterranean diet, tomatoes, potatoes and citrus fruits were totally unknown. Food was flavoured by the addition of seasonings (salt and pepper, cinnamon, cloves, various types of cumin, lavender, honey, vinegar, and garlic) and herbs (dill, fennel, rosemary, oregano, capers). The most popular sauce was garos, made of small fry and fish offal blended with salt and old wine, then boiled or left to brew in the sun for around three months. This was used in different variations to flavour all kinds of food (vegetables, meat and fish). Finally, herb beverages such as mountain tea were common, as well as various fruit juices.