72 Journal of Chinese Medicine | Issue 130 | October 2022 The Yin and Yang of Fats and Cooking Oils high fat (LCHF), and consequently not much experience of them. However, both research and our experience as therapists indicate that when fats and oils are ingested without carbohydrates, they produce different effects to when they are eaten together. As already mentioned, most research on high fat (or high SaFa) diets has actually been done on a combination of different fats together with carbohydrates, rather than on fat with no or very low carbohydrates. 6,7,8 Therefore most research villifying fats and animal foods may actually be looking at the damage done at least partly by carbohydrates and PUFAs. In modern China, sugar and omega-6 consumption has dramatically increased, especially in fast foods. This combination potentiates their yin effects of causing obesity and inflammation. 86-90 Interestingly, both high carbohydrate-low fat (HCLF - such as that traditionally eaten in China and Okinawa) and LCHF diets have been shown to be beneficial. Aroma, toxicity and fa wu In general, fish and seafood contain relatively high amounts of omega-3 PUFAs, however when these reek, we are smelling PUFAs oxidising and if we consume them we risk toxicity from the oxidants, an effect known as fa wu 91 in Chinese medicine. Fa wu means ‘expelling things’; it refers to disease that has lain dormant coming to the surface, typically as an allergic reaction with or without skin problems, such as urticaria or eczema. Traditionally there is a Chinese admonition against eating fish or seafood that ‘smells like the sea’. This smell is thought to be indicative of ‘evil qi’ and these foodstuffs are likely to produce toxic effects unless they are detoxified prior to consumption (usually with the use of fresh ginger or perilla leaves during the preparation process). With regards to the Tokelau Migration Study mentioned earlier, where the population gave up their traditional diet of fish, coconuts and breadfruit. - a healthy diet in general to prevent the chronic diseases we see in the West - the resulting health problems were skin diseases, asthma and infections. 92 Skin diseases and asthma are typical problems related to fa wu. The famous dermatologist, Dr Yu Wenqiu (with whom one of the authors [PT] studied in Nanchang) once said that he had noticed that industrially-raised animals such as battery chickens were more fa wu than traditionally-raised animals. We believe that PUFAs, especially omega-6, can have a fa wu effect, most likely due to their oxidising effects; this has a connection to the aforementioned yin-effects of omega-6, which causes an increase in dampness. Fats and oils in the Chinese materia medica Cholesterol is found where there is high fat content in animal products; these foods usually contain many other nutrients - such as Vitamin A - which are unique to animal products. In Chinese medicine, these foods are considered particularly tonifying. A review of 200 different traditional cultures showed that animal fats were highly esteemed, and associated with fertility, health, sacredness and wealth. 93 Even though the Chinese are famous as a culture that consumes relatively more carbohydrates and less fat, they traditionally also appreciated animal fats such as butter. One Chinese term for fat is gao 膏, which refers to a dense, rich fluid that is associated with essences and fertility. Oils are often called you 油. In the Bencao Gangmu (Compendium of Materia Medica, BCGM), the pig is the first animal described in the section for domesticated animals; it states: ‘Congealed fat is called zhi 脂 and not congealed is called gao 膏 or you 油’. 94 The BCGM and other materia medicas contain many descriptions of the effects of eating pork and lard; interestingly there are more contraindications for pork than for lard. Although the BCGM is a later compilation of earlier knowledge, it contains little information about fats. There is information about lard, butter and sesame oil, and a brief mention of coconut pulp (but not oil), which has the effect of reinforcing qi and dispersing invading wind. Soy oil and tallow are classified as slightly toxic. Fish oil is briefly described by Li Shizhen as sweet, warm and slightly toxic and capable of treating hard masses. A common effect of many fats and oils – most of which are dense, cooling and moistening - is to descend qi. Lard, butter, goat/lamb fat, sesame oil and rape seed oil all moisten the intestines; lard and sesame oil descend the qi of the placenta (helping elimination of the afterbirth) and lard assists the bladder in urination. According to the BCGM, if we compare the most important fats/oils (lard, butter and sesame oil), we can see that they counter or eliminate blood stasis (which probably only applies if the patient has a dry rather than damp constitution). Lard is described in the BCGM as ‘sweet, a little cool, not toxic … it facilitates the function of the intestines, eases urination, eliminates five kinds of jaundice and oedema … facilitates blood circulation and disperses invading wind heat. It moistens the lung … moistens and brightens the skin … promotes growth of hair’. Interestingly, Sun Simiao notes that lard can treat intoxication from eating liver. Liver is a concentrated source of vitamin A, which if eaten in excess amounts can be toxic. Lard might be one of natures best sources of vitamin D, and vitamin A and D counter the potential toxic effects of each other. We also find traditional external uses of lard to treat dry lips, chapped hands and feet, and to treat hair loss when ingested together with millet. Other folk recipes include a soup containing lard and kelp to treat nail fungus. Butter is described in the BCGM as ‘Sweet, a little cooling, non-toxic … it invigorates the five zang and