The earliest recorded usage of the term "macrobiotics" is found in the writings of Hippocrates. Translated literally, macro is the Greek word for "great" and bios is the word for "life." Macrobiotics is used by its practitioners as a tool that allows one to learn to live within the natural order of life. Throughout history, philosophers and physicians from many parts of the world have used this term to signify living in harmony with nature, eating a simple, balanced diet, and living to an active old age.

The modern practice of macrobiotics was started in the 1920s by a Japanese educator named George Ohsawa. Ohsawa is said to have cured himself of a serious illness by changing to a simple diet of brown rice, miso soup, and sea vegetables. At the core of Ohsawa's writings on macrobiotics is the concept of yin and yang. In Chinese philosophy, the opposing forces of yin and yang govern all aspects of life. Yin-representative of an outward centrifugal movement-results in expansion. On the other hand, yang-representative of an inward centripetal movement-produces contraction. In addition, yin is said to be cold while yang is hot; yin is sweet, yang is salty; yin is passive, yang is aggressive. In the macrobiotic view, the forces of yin and yang must be kept in balance to achieve good health.

The macrobiotic diet, therefore, attempts to achieve harmony between yin and yang. To this end, foods are classified into yin and yang categories, according to their tastes, properties, and effects on the body. The two food groups-grains and vegetables-that have the least pronounced yin and yang qualities, are emphasized in the macrobiotic diet. Eating these foods is thought to make it easier to achieve a more balanced condition within the natural order of life. Foods considered either extremely yin or extremely yang are avoided.