Obesity has been one of the major health concerns for many years. There are many ancient documents and references regarding being obese or thin. According to the Lingshu (靈樞), published in Chin-Han(秦漢) era, the oldest classic of oriental medicine, people with different physical types (i.e. being obese or thin) need different applications of acupuncture.

    “Fat people have large shoulders and armholes with dark and tough skins..........This type of people should be applied with deep and prolonged acupuncture..........On the contrary; thin people have haggard faces and bodies with thin skins............ These people need shallow and fast acupuncture.”

For thousands of years, people knew differences between what is normal and abnormal (i.e. fat or thin). The matter of being fat or thin has been always the main interest in medical history.

Modern nutritionists suggest various theories for explaining causes of obesity. Among the theories, the most compelling one is the imbalance between energy intake by metabolic factors and energy consumption. This means obesity is the result of excessive accumulation of body fat or energy, which is caused by too much food and/or too little exercise. However, the theory does not give a complete answer for the reason of being obese, because there are certain people who have a higher risk of becoming obese than other people despite eating the same amount of food.

The other theories for explaining obesity are environmental theory and genetic theory. The environmental theory suggests various environmental inducements in relation with life style habits, cultural or socioeconomic status can cause obesity. For example, modern environmental factors such as high calorie foods and sedentary life style can induce obesity. However, it is unclear whether the environmental inducements are the only causes of obesity without excluding genetic factors.

The latter theory, genetic theory, explains obesity is genetically inherited, which is supported by a number of research results. In this theory, people who have family history of obesity may have higher risk of being obese than other people. For instance, if both parents have normal weights, the obesity rate of their children is only 10%. However, if one of the parents is obese, the rate increases to 50% and if both parents are obese, the rate increases to 80%. This result suggests that the genetic factors cannot be disregarded for explaining obesity.

Set Point (Fixed Point) Theory

The most promising theory for explaining obesity factor is the “Set Point Theory”. This theory seems to use similar approach with those of constitutional medical theory for explaining obesity factors.
According to the Set Point Theory, which was published by Schwartz and Seeley, people are born with certain set (fixed) range of weights like skin, eye or hair colors or heights. That is, body shapes (i.e. fat, thin or normal) and body weights are genetically predisposed. We cannot choose to be fat or thin! Every person is born with his/her own range of weight, which is called set point or fixed point. For example, some people are born with height of 170cm and weight of 70-90 kg, while others are born with 160cm and 50-70 kg. The set range of weight can be changed by dieting during lifetime, but it is very difficult to change the set point, because of human body's tendency for homeostasis to keep the original weight range.

People who has experiences of dieting know how hard to lose and maintain their weights. When people start diet, they lose several pounds within a few weeks. However, after then, although they restrict their food intakes by dieting, some people regain their original weight or even more by yoyo effects. The result is caused by human body's tendency to keep and restore its set point weight despite our painstaking efforts to lose weight.

If we decrease food intakes to change our set point weights, not only our body weights decrease below the set point, but also our metabolic activity decreases and thus our body starts to conserve energy. In this case, decreased body activity with hunger results in body movement toward losing fewer calories such as more sleep or loss of body temperature. For example, people with loss of appetite due to dieting are more sensitive to the cold or suffer from disorders of menstruation.

On the other hand, when the body weight increases above the set point, the metabolic activity increases. With increased metabolic activity, our body burns the excessive calorie intakes by increasing body temperature. Accordingly, our body weight is affected by various body functions such as body temperature, blood pressure and maintains its set point weight by our body adaptation mechanism.

The Set Point Theory suggests the followings: Some people born without obesity factor cannot be obese, even though they are exposed to obesity inducing environments. However, no matter how hard they may try, some people are predisposed to be obese, because they are born with obesity factor.

To easily discover which organ causes a certain disease, organs in the chart are transcribed in bold case. When The above Set Point Theory has a similar viewpoint with constitutional medicine, which describes “Obesity is determined by body constitution.” Although the Set Point Theory suggests a proper approach for explaining obesity without including inducing or external factor, the theory does not give a sufficient answer to physiological and/or inherited factors, which determines the body type of obesity.

Like the Set Point Theory, the constitutional medical theory takes the inborn body shape theory. However, the constitutional medical theory focuses on zhang-fu [the five viscera (liver, lungs, heart, kidney, and spleen) and the six entrails (of gall bladder, stomach, small and large intestines, the paunch, the bladder and the bowels)] rather than body shape: our body shape is determined by our inborn organ structure. That is, each person is born with his/her unique organ structure, which decides his/her constitution. The imbalance between functional increase and decrease of relevant zhang-fu is the main reason of obesity. Therefore, anyone who is exposed to obesity factors cannot be fat. Only some people who has certain internal organ related to obesity can become obese. In other words, anyone born with obesity-free organ may not be obese, even though he or she is exposed to obesity factors. Because each person has different capacity for coping with the same causes depending on his/her constitution. In this viewpoint, “Obesity is a phenomenon of body constitution.”

(Table1) The Organ Structure of Eigh Constitutions

An obesity-prone type is the person who is born with strong pancreas, precisely pancreas yang, which is in charge of digestive and absorptive functions. As shown in table 1, a Yol-Soyangin, who is born with the strongest pancreas, is the most obesity-prone type or constitution, and who is followed by a Yol-Taeumin, the person with the second strongest pancreas.

In addition, Table 1 provides that a Han-Soyangin also has the organ structure of a strong pancreas (from strongest to weakest: pancreas > liver > lung > kidney). Unlike other obesity-prone types, the Han-Soyangin can become overweight, but not obese. It is because the physical constitution of a Yol-soyangin has excessive “pancreas yang”, while that of a Han-Soyangin is deficient in “kidney yang”. Besides, the strong pancreas of a Han-Soyangin does not imply excessiveness of “pancreas yang”, but “pancreas yin”. A Yol-Taeyangin also has the organ structure of the second strongest pancreas. As described in the case of the Han-Soyangin, a Yol-Taeyangin can become overweight compared with a Han-Taeyangin, but not easily get obese, because the constitution of Taeyangins has a strong lung, which is the source of exhaling.

Accordingly, Yeol-Soyangin with the strongest pancreas-yang has the highest risk of being obese and Yeol-Taeumin has the second highest risk of obesity. In spite of the above facts, due to lack of clear diagnosis method of physical constitutions and medical education, there is a misconception that obese people are Taeumin, not Soyangin. In the Sasang medical society, this problem has been a controversial matter.

As discussed, in oriental medicine, people are born with certain constitutional zhang-fu types, which determine their body type, either thin or obese. Compared with the oriental medical viewpoint of obesity, the western medicine was concentrated on demonstrating the results (symptoms) of obesity rather than its causes. In Korea, any person who easily gains weight or is obese is called “weight gaining type only with water intake”. Likewise, in western society, the person is called “weight gaining type only with seeing food” or “Obesity-prone (OP) type”, while the other type of person, who does not easily gain weight despite eating large amounts of food, is called “Obesity-resistant (OR) type or thin type”.

Every human being is born with either OP or OR type. In practice, however, it is not easy to clarify and classify each person's obesity type, since obesity is caused by many external factors as well as internal characteristics and each person has different constitution and inborn weight range. Even if people are born with OP type, they cannot be fat or obese, if they are living in destitute environment without sufficient nutrition supply. In this connection, OR type people can gain weight or be over weight, if they are provided with sufficient quantity of nutritious foods. For example, we can see many thin type peoples in North Korea, Africa or Vietnam and a number of obese peoples in the United States or other western countries. However, what is clear is every human being has his/her own inborn weight range, whether he/she is either OP or OR type. During his/her lifetime, his/her weight either increases or decreases within the set (fixed) range of the inborn weight.

As discussed, in oriental medicine, human being is born with certain weight range depending on his/her zhang-fu type. In this point of view, there can be no standard weight for human. The standard weight means the most appropriate and efficient weight for human to maintain health and physical activity. In general, the standard weight is estimated either by subtracting 100 (110 for children) from his/her height (Broca's Index) or by subtracting 100 from his/her height and multiplying 0.9 (Broca's variable). Besides the above, there are many other body type indexes for measuring the standard weight. However, these mechanical methods which do not take regard in inborn weight of each individual do not give a satisfying answer or approach to keeping our health just by maintaining our weight within the standard weight.

One of my female friends who is 47 years old and Yeol-Taeumin has height of 156 cm and weight of 57 kg. Before marriage, her weight was 46 kg, but after marriage and giving birth twice, her weight increased to present level. Since she did not want to gain weight and lose weight, she started dieting and has been eating smaller amount of food for 7 ~ 8 years. During diet, she usually ate appropriate amount of food in lunch and ate smaller amount of food in dinner, but skipped breakfast. In spite of her dieting efforts, she has not lost any pounds since then, which implies her present weight may the lowest figure within her set point weight range (inborn weight range).

Recently, she received a comprehensive medical testing from a general hospital. The doctor of the hospital told her to lose 3 or 4 kg to maintain her health, based on the estimated standard weight using the Broca's variable. In her case, her ideal standard weight is around 51kg. Actually, she succeeded in losing weight to 53kg (she lost 4kg.) by strengthening her diet two years ago. However, she did not look healthy at all and everyone asked whether she was having a serious health problem. She also felt very tired, lethargic or powerless and thus she gave up the dieting. In this case, it was not desirable for her to lose weight to her standard weight. Considering her inborn constitution, her standard weight with her height (156cm) should be 57 kg rather than 51kg for keeping her health. In oriental medicine, there is no standard weight for everyone and each person has its own standard weight according to his/her inborn weight (set point weight).

Regardless of the above, more and more people are trying to lose weight by diet or exercise, which is one of the negative impacts of socio-pathological phenomena caused by narrow-minded notion. People continue to struggle with losing weight, because of the wrong idee fixe, “Fat is ugly and thin is beautiful.” In the old days of Korea, a beauty was a woman with a full-moon-shaped face, which was a natural thing considering a Korean's body structure. However, these days the beauty standard has changed to western beauty types. Many Koreans who wants to look like Caucasians are doing unnecessary plastic surgeries such as cutting their cheekbones and other facial surgery. Likewise, just as old Chinese women who had unnatural beauty standard such as slim waist and small feet bound their feet, it is not natural to seek thin body image with disregarding own inborn weight.

Of course, obesity induced by excessive nutrient intake, which also causes various diseases such as diabetes or hyperpiesia, needs appropriate medical treatment for health maintenance. Aside from the above, we should dump the biased beauty aesthetics that fat is ugly and thin is beautiful, which was promoted by diet industry. We should accept and love our inborn type of body. If we bear this in mind, we will not only identify our true colors, but also find real health and happiness.