When we ingest food, it has a certain effect. It has a taste that moves us a certain way, it has a thermal quality that warms or cools us, and it has a substantial quality that either builds or reduces energy, fluid, or mass. These things influence who we may become. For instance, a child born thin and feeling cold and shy could help himself by eating mildly sweet and spicy food that also builds mass and warmth; on the other hand an adult who sits at a stressful job would do better with lighter, bitter and sour fare that cools the head and helps guide the qi down and in for a steady idle.
How can we know the nature of such food? Actually, such knowledge is inherent in any traditional culture. Oriental Medicine has simply lent it a language, a way to think about food as medicine, as having a predictable effect on the body. So here it is.
Food tastes sour, bitter, sweet, spicy, or salty, or a combination of these. Sourness guides the qi /in/, bitterness /descends/ the qi, sweetness /wallows/ and also /spreads out /the qi, spiciness goes /up /and /out,/ and saltiness /suspends/ and also moves /down./ For example, to aid in digestion, some bitter leafy greens help by guiding the food down through the bowels; or to rid the beginnings of a common cold, one may use spicy food like scallions or ginger to push the pathogens up and out.
Food also has a thermal nature, regardless of its external temperature. For example, peppermint leaf tea cools the head and chest whether drunk hot or on ice, whereas cinnamon bark warms the loins and limbs whether eaten in ice cream or a hot apple pie. In general, thermally warm food arouses the body and its senses and emotions, while thermally cool food settles them.
Finally, food is often what it looks like; this is called its law of signature. For instance a celery stalk is mostly light fibrous material that cleanses, cools, and rids the body of excess weight and heat, whereas a potato is a dense amorphous mass that adds energy and weight to the body. Spinach has both a nourishing quality, owing to its dark color, and a cool cleansing quality, being a delicate leaf. /Whole/ grains are concentrated sources of energy and mass like the potato, yet also have a germ that moistens, and bran that cleanses. Most legumes, nuts, and animal meat are rich and fleshy, and hence build flesh, whereas oils and animal’s blood and milk are rich and fluid, and nourish our blood and hormonal fluids. Minerals like whole salt help suspend fluids to sustain life, while water is the most basic and neutral fluid there is.
Now, in general, we as humans do well with a smattering of all these qualities of food. We enjoy activity and being inspired, and so do well with energy producing, warm, sweet and spicy fare. Yet also, we need to rest and reflect on our experiences, and so benefit from cooling, sour and salty fare as well. We need to build flesh and blood with dense, rich, and mildly sweet food, and also shed it with light and bitter food. We use food to help express our instincts and emotions, like leafs, fruits, flowers and animal’s meat, while we may reserve these motivations with seeds, nuts, roots, and animal’s milk. And, washing it all down, water acts as the great harmonizer, humble of itself, there to bring all things together.
Contrast this to a tiger, whose diet of mostly other animal’s raw flesh and blood define it as a fierce and hot-blooded creature. Nonetheless, even a tiger needs to eat a modicum of green leafy matter to cleanse and cool itself, as well as drink quite a lot of water! In fact, it is this cooling and calming fare that affords a tiger her rich and stimulating diet; otherwise she would burn herself out and lose her strength and agility.
This is the basic principle that is largely ignored in modern societies. Americans, in particular, feast mostly on intensely sweet, rich, and thermally warming food. Not only is this diet at obvious odds with a sedentary and intellectual lifestyle, it can hardly sustain any lifestyle at all, because of its lack of basic balance.
On the other hand, a balanced meal makes the body feel good and in control. Traditional cuisine is balanced relative to the people and climate it serves. Ideas can be had from perusing any cookbook with cultural roots, be it Asian, Indian, European, African, or Native American. The common themes are the use of fresh local produce, balancing tastes and thermal qualities, and using a variety of signature food. Beyond the basics and the larger cultural values, however, one may also wish to add a personal twist to meals, especially if one feels ill or has chronic complaints. To know what is appropriate to one’s self begs awareness and a close relationship to nature. These are the roots of Oriental Medicine.