Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index

Background: Although international interest in classifying subject health s tatus according to adiposity is increasing, no accepted published ranges of percentage body fat currently exist. Empirically identified limits, popula tion percentiles, and z scores have all been suggested as means of setting percentage body fat guidelines, although each has major limitations. Objective: The aim of this study was to examine a potential new approach fo r developing percentage body far ranges. The approach taken was to link hea lthy body mass index (BMI; in kg/m(2)) guide lines established by the Natio nal Institutes of Health and the World Health Organization with predicted p ercentage body fat. Design: Body fat was measured in subjects from 3 ethnic groups (white, Afri can American, and Asian) who were screened and evaluated at 3 universities [Cambridge (United Kingdom), Columbia (United States), and Jikei (Japan)] w ith use of reference body-composition methods [4-compartment model (4C) at 2 laboratories and dual-energy X-ray absorptiometry (DXA) at all 3 laborato ries]. Percentage body fat prediction equations were developed based on BMI and other independent variables. Results: A convenient sample of 1626 adults with BMIs less than or equal to 35 was evaluated. Independent percentage body fat predictor variables in m ultiple regression models included 1/BMI, sex, age, and ethnic group (R val ues from 0.74 to 0.92 and SEEs from 2.8 to 5.4% fat). The prediction formul as were then used to prepare provisional healthy percentage body fat ranges based on published BMI limits for underweight (<18.5), overweight (greater than or equal to 25), and obesity (greater than or equal to 30). Conclusion: This proposed approach and initial findings provide the groundw ork and stimulus for establishing international healthy body fat ranges.