Obesity is a major nutritional problem in many countries of the world and currently it is also quite prevalent in Taiwan. As a result, advertising costs for companies in the beauty and dieting industry total from one hundred million to many billions of dollars per year. There is much evidence that shows that the body mass index in relation to death rate presents in a J shaped curve. Thus we can see that obesity is highly dangerous to one's health. Furthermore evidence shows that being obese can increase the risk of many life threatening diseases, including type 2 diabetes, cardiovascular disease, gallbladder diseases, hormone sensitivity and gastrointestinal cancer. Obesity also leads to many non life threatening problems, such as back pain, arthritis and infertility. In many westernized countries people who suffer from obesity may also suffer psychological problems and have difficulties in social interactions.