Why desert comes last

When it comes to doing a great number of things, it is difficult to imagine doing them any other way than how we are used to. It feels as if our most deeply rooted habits were something natural and predetermined. The same goes for preparing and consuming food. Many would be surprised to learn that the order of courses in a meal as well as the established combinations of tastes in an average European meal today have its origins in the middle of the seventeenth century. It was at that time that the wealthier Europeans made significant changes to their eating habits, habits that have been taken for granted to this day. The reason for changing the established diet was a new scientific theory about how digestion works and what healthy nutrition really means.

Nature as one big kitchen

Since ancient times, people have been aware of the fact that their health depends greatly on the food they consume. In the time of the High Middle Ages and Renaissance there was a rule defining the health of an individual as a state in which his bodily fluids are in just the right proportions. Food was an important factor in maintaining physical balance as the doctors of the time could not rely on many methods with which the balance between bodily fluids could be regulated. When someone was severely ill, they would try to reestablish the balance within the body by controlled blood-letting. That is why the wealthier part of the population that could afford to choose the kind of food they would eat, usually followed the principles of healthy nutrition.

According to ancient medical tradition which was based mostly on the works of the Hippocratic Corpus, Aristotle’s essays and Galen’s treatises, digestion was viewed as food being cooked inside the human body. Just as, in nature, the sun heats the earth so that plants grow from it and bear fruits, the inner flames of the human body were believed to “cook” the ingested food further until it was transformed into bodily fluids, while the remains were disposed of in the form of excrements which would then fertilize the earth, and the natural cycle could repeat.

The image of the cosmos as a big kitchen in which natural flames induce the growth of living nature and the circulation of matter was reflected in the image of the human body as a miniature version of this cosmic kitchen in which the inner flames cook the ingested food. According to this model of nature and man, the most frequent advice doctors gave their patients was that they should boil their food as much as possible, ensuring that their digestive mechanisms are put under less stress, and that they should consume balanced food. Of course, this balance should be viewed according to the way nutrients were classified at the time.

The theory of four elements

At the time, different types of food were classified according to Aristotle’s established theory of four elements from which the world was believed to have been created. Individual elements had been attributed corresponding characteristics. Fire was hot and dry, water was moist and cold, air was hot and moist, and earth was dry and cold. Food was classified in accordance with these four characteristics; pepper, for example, was put into the category of fire while melons, mushrooms and fish were classified under water. Because it was believed that the human body should ideally be moderately warm and moderately moist, meals were planned accordingly. A healthy diet meant eating food which came as close as possible to the ideal ratio of individual elements in the body.

The ideal meal was believed to be a sort of warm and relatively squishy porridge, because it contained all the characteristics that were supposedly best for the body. It is interesting that raw vegetables were, consistent with the principles of the time, considered unhealthy and appropriate merely as food for the poor. On the other hand, sugar was believed to be a very healthy nutrient and an ideal food additive which was also sold in pharmacies. Because it was relatively expensive, it was usually kept safe or even locked up in the kitchen.

New science, new menu

In the 17^th century, however, the diet of wealthier Europeans underwent a significant change. The ideals of nutrition had changed and so had advices for a healthy diet. In her books and articles, Rachel Laudan, a science historian researching the history of relations between science, medicine and nutrition, has come up with several convincing arguments which indicate that the change in the eating habits of the rich around the year 1650 happened mostly because of new scientific discoveries. The main reason for these changes was a new scientific theory about how human digestion worked and how, in nature, one substance changed into another. If scholars before mostly compared the happening in nature and the human body to the process of cooking, which supposedly causes substance to change, the central natural process now became fermentation. In the most general terms, fermentation is a chemical process in which carbohydrates, like sugars, are transformed into alcohol and acids. With the fermentation of yeast, for example, one can produce wine, beer and vinegar. With the fermentation of lactic acid bacteria, milk changes into yogurt and other dairy products. Fermentation also contributes to the bread rising process, releasing carbon dioxide which leavens the dough by creating the bubbly structure typical of bread.

The chemistry of tastes

Scholars that, a few centuries ago, studied the branch of science today known as chemistry, used fermentation and distillation to isolate individual key ingredients of plants and search for new active healing ingredients. Because fermentation was present throughout nature as well, the theory was quickly established that the essence of human digestion was not some extended process of cooking food that takes place in the stomach, but the process of fermentation itself.

The system of food classification was quickly adapted to the new theory of digestion. Aristotle’s four elements with their usual characteristics were replaced by a system of classification according to three new ideals of pure substances which were first introduced in chemistry. The three ideal substances were salt, oil and quicksilver. However, these are not to be understood in the modern sense of the words, but the more (al)chemical sense, pertaining to the roles of these substances in the processes of fermentation and distillation. The chemists of the time discovered that in the process of distillation substances are usually separated into three parts: volatile liquids, “oily” substances and solid residues.

Sugar becomes poison

Oil was the term used to designate substances that did not evaporate during the boiling process, in contrast to alcohol which was classified as one of the “quicksilver” substances. Among the food items that could be found in the kitchen, butter, lard and olive oil were the closest to the “element of oil”. Apart from regular salt, flour and similar solid substances were part of the “salt” group. The typical representatives of the “quicksilver” group were vinegar, wine and other alcoholic beverages, as well as certain flavors of meat and fish. With the new division of food, oils especially gained importance, becoming the key ingredient of a variety of sauces. The new food classification system caused a noticeable change in eating habits.

As for sugar, doctors began to realize that it was far from the ideal nutrient it was once believed to be. They discovered, for example, that it damaged teeth, and was also found in the urine of several patients which was later attributed to diabetes. According to the new division of nutrients, sugar was no longer believed to be an ideal type of food, and some doctors came close to describing it as poison. That is why during the last few centuries our main courses have no longer contained excessive amounts of sugar, and sweets have only been consumed in small quantities at the end of the meal.