In Chinese philosophy, the concept of yin yang is used to describe how polar, interconnected and interdependent or seemingly contrary forces manifest in the biological world, and how they cause each other to happen in succession. The concept lies at the origins of many branches of classical Chinese science and philosophy, as well as being a primary guideline of traditional Chinese medicine.
Yin yang dualities only exist in relation to each other. Everything has both yin and yang aspects, but either of these aspects may manifest more strongly in particular objects, and may ebb and flow over time. Many natural complementary opposites—e.g. dark and light, female and male, low and high, cold and hot— are thought of as occurrences of yin and yang (respectively).
It is important to see that yin yang dualities do not account for good / bad distinctions or other dichotomous moral judgements. Most contrary, yin yang account for the idea and importance of balance.
Under the philosophy of letting food be your medicine, yin yang dualities and the importance of their balance, have been adopted by plenty of diets and nutritherapies around the world.
There are foods predominantly yin or yang, and foods containing both yin yang forces in quite a balanced way. In simple terms, yin is expansive, cool, moistening, light and upward growing. Yang is contractive, warm, drying, compact and downward growing. The ideal diet should contemplate a balance of these two energies. However, one should always have present that all foods share the presence of yin yang forces, usually one force predominating.
Yin foods (simplistically, most vegetables and fruits, sweets, stimulant drinks and water) are cooling to the body and turn down the internal thermostat. Yang foods (simplistically, salty foods, seaweeds, fish and meat with their concentrated protein) are heating.
Cooking food methods are also of great significance regarding yin yang balance. Quick cooking (light sautéing, rapid stir-fry, steaming) is a yin method, the end outcome is food that is still crisp and intact. Long cooking (baking, stewing, roasting and braising) are yang methods, the end outcome is concentrated foods that tend to have merging flavours and textures.
Seasons are definitively important to fine-tune one’s diet balance. A very yang season –summer– will ask for a more yin diet, with fresher and moist foods cooked in a lighter way or raw. A very yin season –winter– will ask for a more yang diet, with denser and dried foods cooked using longer methods or baked.
A list follows as a basic guideline to yin yang in foods, from foods with a stronger predominance of yin to a stronger predominance of yang. Ideally, one would like to choose foods from the middle range list to keep a balanced diet.
Alcohol, sugars, coffee / spices / chocolate / caffeinated or stimulant teas, tropical fruits and juices, fats and oils, nightshade vegetables (potatoes, tomatoes, peppers, aubergine), fresh and soft dairy products (milk, fresh goat cheese).
Balanced / neutral foods
Temperate fruits (apples, pears, berries, stone fruits), nuts, leafy green vegetables, round vegetables, beans / tofu / tempeh, root vegetables, sea vegetables, whole grains, fish.
Poultry, miso / tamari / shoyu, salty and aged cheeses, read meat / eggs, caviar, sea salt.