According to a recent survey of 3,256 local citizens by the World Health Organization (WHO), about 44.5 percent of citizens are overweight, and up to 20.9 percent are obese.

Obese people have an abnormally high proportion of body fat, which is most often defined as being 20 percent or more over ideal body weight.

Recently, the WHO and International Obesity Research Association issued a new body mass index (BMI) for people in the Asia-Pacific area. BMI is calculated as weight in kilograms divided by height in meters squared.

According to the new body mass index, people in the Asia-Pacific area with a BMI of 23 or over are regarded as overweight, and those with BMI of 25 or over are obese. This BMI is lower than for people from Europe and America, due to the special physiological characteristics of Asians.

Experts predict that the number of overweight and obese people will double using the new BMI.

Morbid obesity is a severe form of obesity in which a person is 100 or more pounds overweight. Morbid obesity is considered by health officials to be a disease. And the disease has been linked to shortened life expectancy. According to C. Everett Koop, former Surgeon General of the US, obesity is the second leading cause of preventable death in the US.

"Being obese is more than having a big size, it can seriously affect health and longevity, because it's associated with elevated serum cholesterol, elevated blood pressure and others," said Robert A. Rabkin, director of Pacific Institute of Surgery for obesity.

Doctors have found that excessive weight also increases the risks for diabetes, gout, coronary heart disease, asthma, gallbladder disease, infertility and some types of cancers.

Besides physical inconveniences, obese people usually suffer more pressure than normal-size people. Some become socially isolated because of their size.

"The underlying causes of overweight are unknown," Dr. Rabkin said. "The basic mechanism is an imbalance between caloric intake and energy expenditure, but why this imbalance occurs is unclear."

However, doctors have found that obesity results from a combination of factors, including genetics, environmental influences, emotional trauma and overeating.

Since the pattern of food processing by the body has a genetic basis, multiple members of a family may be obese, Rabkin said.

During a study on twins of obese parents, medical researchers have found that they have nearly the same weight, even when they are raised in different families.

Doctors believe the increase in obesity, especially among children, is due directly to unhealthy diets that are high in calories, such as fast foods and fried foods.

Obesity is not limited to certain places or types of people. According to the World Health Organization, the obesity epidemic affects 115 million people.

In 1995, there were about 200 million obese adults worldwide and 18 million children under the age of five classified as overweight. As of 2000, the number of obese adults has increased to over 300 million.

Diet and exercise are the methods most frequently used by both sexes when they are attempting to lose weight.

For people who are 50 kilograms or more overweight, however, diet, exercise and medication are not effective in curing obesity. In fact, the cure rate of such methods is less than 3 percent.

Notwithstanding genetic or environmental factors, it also seems clear that once an individual exceeds a certain obesity level, he or she often can't reverse it because of the complications and restrictions caused the obesity disease itself. A highly effective thermostat at work within the body actually works against the loss of weight.

When caloric intake is severely reduced, a rapid biological adaption occurs. The metabolism slows down in order to conserve energy and preserve the quantity of stored fat.

Even worse is what occurs when the diet is relaxed and the obese individual returns to a normal eating pattern. Weight gain occurs since the same amount of calories ingested now produced a larger surplus due to the more efficient metabolism. This is a barrier which the severely obese patient usually cannot overcome.

It's not possible to hold one's breath for longer than several minutes. After a certain time, automatic subconscious drives take charge. Dieting causes much the same reaction in the body, since permanent fasting is not an option.

Diet and exercise are good in the short term, but long-term dieting can't be maintained and often the exercise can't be sustained. Severe obesity develops gradually from the accumulation of a relatively small surplus in daily food intake above the energy burned up by exercise and normal metabolism.

Since diet and exercise can't achieve a permanent change in either caloric intake or energy expenditure, the permanent reduction in weight is unable to be gained.

Surgery is effective

"Under such situation, surgery is the best and only effective way," Rabkin said.

Since the 1960's, surgeons have developed methods to help fight obesity called duodenal switch.

The surgery reduces stomach capacity, providing initial weight loss, and controls nutrition absorption through the intestines.

The evolution of duodenal switch started from "jejunoileal bypass," to "gastroplasty," and the latest development is "distal gastric bypass/duodenal switch" developed by Rabkin.

"The surgery rearranges the intestines so that the majority of food calories are not absorbed, resulting in progressive, long-term weight loss in most obese people. In addition, a portion of the stomach is removed to reduce the stomach capacity to about six ounces," Rabkin said.

After the surgery, the weight loss is good, with an average 80 per cent loss of excess kilos in 18 months, which remains stable for five years.

Besides the obvious weight loss, the surgery is good medicine for diseases that result from obesity.

The blood levels of cholesterol and triglycerides will be reduced, often to normal or even lower levels, and high blood pressure will be lowered. As for diabetes, blood sugar levels will often become normal, and insulin requirements reduced or eliminated altogether.

Doctors believe early prevention is the best way to fight obesity and overweight, including sufficient exercise and healthy diet.

(Shanghai Star 05/10/2001)