BACKGROUND: In Taiwan, the availability of a high-fat and high-energy diet has steadily risen over the past 30 y, while people have become increasingly sedentary. This lifestyle of poor diet and little physical activity has caused the prevalence of obesity to increase among adults and children. Obesity and associated chronic disease risk factors are becoming important public health issues. The purpose of this study is to evaluate the prevalence and secular trends of being overweight and obese among school children in Taiwan. METHODS: We conducted a cross-sectional survey among junior high school students in Taipei in 1994 to ascertain a representative distribution of demographic, lifestyle and biochemical characteristics, including several cardiovascular disease risk factors. After multistage sampling of 85 junior high schools in Taipei, we randomly selected 1500 children for this survey. We defined being overweight and obese based on ideal body weight (IBW) criteria. Children are considered to be overweight if their body weight is 110-120% of IBW, and obese if their body weight is greater than 120% of IBW within age- and gender-specific strata. RESULTS: In general, obese children have higher blood pressure, plasma glucose and triglyceride levels and lower high-density-lipoprotein cholesterol levels than normal-weight children. From 1980 to 1994, the mean value of body weight increased significantly over increases in body height (especially among boys). Although the percentage of overweight children remained steady from 1980 to 1994 in both genders, the prevalence and trends of obesity increased significantly, especially among boys and older girls. CONCLUSION: From this survey we find that in Taiwan from 1980 to 1994 body weight increased dramatically over body height among school children. The prevalence of obesity also increased significantly, especially among boys, while the percentage of overweight children did not vary. Overall, this study indicates that obesity and the adverse effects of being over the ideal body weight is no longer just a problem of Western countries. International Journal of Obesity (2001) 25, 170-176 | 
