OBJECTIVE: To review the main methods to assess body composition of children, emphasizing validation studies. DATA SOURCES: SciELO, Science Direct and Pubmed databases were searched using the following key-words: "validation", "body composition", "child", "body mass index", "hydrostatic weighing", "plesthymography", "electrical bioimpedance", "skinfold, anthropometry, waist circumference. Studies published between 1990 and 2007 in English and Spanish, as well as recognized classical works on the theme, were selected. DATA SYNTHESIS: The most widely used indirect methods to evaluate the body composition of children were plesthymography and dual energy X-ray absorptiometry. Among the double indirect methods, the most frequently used ones were body mass index, skinfold thickness, electrical bioimpedance, waist circumference, waist-to-hip ratio, conicity index and waist-to-height ratio. Higher correlations were found for electrical bioimpedance and body mass index. CONCLUSIONS: There are many methods to evaluate a child's body composition, each one with advantages and disadvantages. Before starting the evaluation, an effective method must be chosen to identify the problem, considering costs, the evaluators' skills, timing, acceptance by the target population and possible risks to health.
body composition; child; anthropometry; nutrition assessment