The period between c. 500 and 1300 saw a major change in diet that affected most of Europe. More intense agriculture on an ever-increasing acreage resulted in a shift from animal products, meat and dairy products to various grains and vegetables as the staple of the majority population. Before the 14th century bread was not as common among the lower classes, especially in the north where wheat was more difficult to grow. A bread-based diet became gradually more common during the 15th century and replaced warm intermediate meals that were porridge- or gruel-based. Leavened bread was more common in wheat-growing regions in the south, while unleavened flatbread of barley, rye or oats remained more common in northern and highland regions, and unleavened flatbread was also common as provisions.
The most common grains were rye, barley, buckwheat, millet, and oats. Rice remained a fairly expensive import for most of the Middle Ages and was grown in northern Italy only towards the end of the period. Wheat was common all over Europe, but was more prestigious and thus more expensive. The finely sifted white flour that modern Europeans are most familiar with was reserved for the bread of the upper classes. As one descended the social ladder, bread became coarser, darker, and its bran content increased. In times of grain shortages or outright famine, grains could be supplemented with less desirable substitutes like chestnuts, dried legumes, acorns, ferns, and a wide variety of vegetable matter.
One of the most common constituents of a medieval meal, either as part of a banquet or as a small snack, were sops, pieces of bread with which a liquid like broth, or sauce could be soaked up and eaten. Another common sight at the medieval dinner table was the frumenty, a thick wheat porridge often boiled in a meat broth and seasoned with spices. Porridges were also made of every type of grain and could be served as desserts or dishes for the sick, if boiled in milk (or almond milk) and sweetened with sugar. Pies filled with meats, eggs, vegetables, or fruit were common throughout Europe, as were turnovers, fritters, doughnuts, and many similar pastries. By the Late Middle Ages biscuits and especially wafers, eaten for dessert, had become high-prestige foods and came in many varieties. Grain, either as bread crumbs or flour, was also the most common thickener of soups and stews, alone or in combination with almond milk.
Fruit was popular and could be served fresh, dried, or preserved, and was a common ingredient in many cooked dishes.
Since sugar and honey were both expensive, it was common to include many types of fruit in dishes that called for sweeteners of some sort. The fruits of choice in the south were lemons, citrons, bitter oranges (the sweet type was not introduced until several hundred years later), pomegranates, quinces, and, of course, grapes. Further north, apples, pears, plums, and strawberries were more common. figs and dates were eaten all over Europe, but remained rather expensive imports in the north.
Vegetables such as cabbage, beets, onions, garlic and carrots were common foodstuffs. Many of these were eaten daily by peasants and workers, but were less prestigious than meat.
Cookbooks, intended mostly for those who could afford such luxuries, which appeared in the late Middle Ages, only contained a small number of recipes using vegetables as the main ingredient. The lack of recipes for many basic vegetable dishes, such as potages, has been interpreted not to mean that they were absent from the meals of the nobility, but rather that they were considered so basic that they did not require recording.
Carrots were available in many variants during the Middle Ages: among them a tastier reddish-purple variety and a less prestigious green-yellow type. Various legumes, like chickpeas, fava beans and peas were also common and important sources of protein, especially among the lower classes. With the exception of peas, legumes were often viewed with some suspicion partly because of their tendency to cause flatulence but also because they were associated with the coarse food of peasants.
Common and often basic ingredients in many modern European cuisines like potatoes, kidney beans, cacao, vanilla, tomatoes, chili peppers and maize were not available to Europeans until the late 15th century after European contact with the Americas, and even then it often took a long time for the new foodstuffs to be accepted by society at large.