Eating is essential to survival, so characters in any novel, including historical ones, will spend a good deal of their time thinking about, preparing, and consuming food. Furthermore, dining has been a social occasion in most societies since the age of the Iliad, and in consequence many key interactions between characters are likely to occur during a meal, whether it is a seductive dinner for two or a medieval feast for a thousand guests.
Obviously, over time eating customs have varied significantly. Fastfood and junkfood don’t fit in the Middle Ages, gourmet feasts are anachronistic in wartime Britain, and a dinner featuring Asian food shatters the authenticity of a novel set in Nazi Germany. Thus knowing what people ate in the period and setting of a novel is essential to creating a realistic atmosphere in an historical novel.
Furthermore, even within a fixed period, differences in diet tell us a great deal about the status and financial condition of an individual. While the lord of the manor feasts on game in heavily spiced sauces with fine white bread and flakey pastry, the peasant would have no meat and eat bread in which sand is mixed with the course-ground flour. Thus providing details about what is being eaten and how can be very useful in helping the reader understand and visualize a specific society.
On the other hand, some historical novelists take it to the other extreme. Cookbooks being some of the most successful best-sellers, they think they too have to provide recipes and lengthy cooking instructions every time one of their characters sits down for a meal. Yet unless the meal itself plays a significant role (e.g. Babbette’s Feast), too much talk about how a meal is prepared interrupts the flow of the narrative and probably doesn’t interest the reader at that particular moment. If he/she is looking for a recipe, they will find a cookbook!
I try to use descriptions of food as a means of saying something about the characters or society. Here’s an example from The Lady in the Spitfire in which food is a device for describing a character’s background and state of mind.
His grandfather clapped him heartily on the back in approval, while his mother just shook her head and turned away, retreating into the kitchen. Then, in a gesture of reconciliation, she called, “I’ve got some fresh-baked cookies in here, Jay.”
In the following excerpt from Leonidas of Sparta: A Boy of the Agoge the objective is simply making a distant, very different society seem less strange by reminding the reader of common experiences like a stand-up snack.
In the final two examples below, food is a means of telling the reader about life in Nazi Germany. Both are from An Obsolete Honor.