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Introduction The increasing prevalence of childhood obesity with a parallel increase in the incidence of associated chronic disease is becoming a major public health problem in Asia, especially in countries [...], Background/Objectives: To develop and cross-validate bioelectrical impedance analysis (BIA) prediction equations of total body water (TBW) and fat-free mass (FFM) for Asian pre-pubertal children from China, Lebanon, Malaysia, Philippines and Thailand. Subjects/Methods: Height, weight, age, gender, resistance and reactance measured by BIA were collected from 948 Asian children (492 boys and 456 girls) aged 8-10 years from the five countries. The deuterium dilution technique was used as the criterion method for the estimation of TBW and FFM. The BIA equations were developed using stepwise multiple regression analysis and cross-validated using the Bland-Altman approach. Results: The BIA prediction equation for the estimation of TBW was as follows: TBW -- 0.231 x [height.sup.2]/ resistance + 0.066 x height + 0.188 x weight + 0.128 x age + 0.500 x sex-0.316 x Thais-4.574 ([R.sup.2] = 88.0%, root mean square error (RMSE) -- 1.3 kg), and for the estimation of FFM was as follows: FFM -- 0.299 x [height.sup.2]/resistance + 0.086 x height + 0.245 x weight + 0.260 x age + 0.901 x sex-0.415 x ethnicity (Thai ethnicity =1, others = 0)-6.952 ([R.sup.2] = 88.3%, RMSE = 1.7 kg). No significant difference between measured and predicted values for the whole cross-validation sample was found. However, the prediction equation for estimation of TBW/FFM tended to overestimate TBW/FFM at lower levels whereas underestimate at higher levels of TBW/FFM. Accuracy of the general equation for TBW and FFM was also valid at each body mass index category. Conclusions: Ethnicity influences the relationship between BIA and body composition in Asian pre-pubertal children. The newly developed BIA prediction equations are valid for use in Asian pre-pubertal children. European journal of Clinical Nutrition (2011) 65, 1321 -1327; doi: 10.1038/ejcn.2011.122; published online 6 July 2011 Keywords: body composition; total body water; fat-free mass; bioelectrical impedance analysis; children; Asia

An analysis of new and previous data on the effect of experimental underfeeding, refeeding and overfeeding on the mobilization and deposition of fat and lean tissue identifies the main determinants of differences among individuals in their regulation of body composition. The metabolic behavior of the human body during excess or insufficiency in food intake is a critical genetic determinant of the tendency to leanness or fatness. The analysis also concentrates on the role these determinants play in the tendency to fatness in rich societies and in the ability of individuals, in subsistence conditions, to adjust to sporadic food availability.