Body composition: the fat-free mass index (FFMI) and the body fat mass index (BFMI) distribution among the adult Austrian population – results of a cross-sectional pilot study

Obesity and obesity-related diseases are among the most prominent health problems in Western countries. In the USA and Europe, more than 40% of the population is overweight [1]. Obesity is normally defined by the body mass index (BMI; kg/m2). BMI values between 18.5 and 24.9 kg/m2 are considered normal; individuals with BMI values from 25 to 29.9 kg/m2 are considered overweight, while those with values over 30 kg/m2 are considered obese [2]. The wide spread use of BMI to define the level of obesity is popular not because it is the ‘best way’ but because it is the ‘easiest way’ to achieve a workable indication. The limitations of BMI have been recognized for many years. BMI does not provide information on either fat-free mass (FFM; kg) or body fat (BF; % or kg). Because research has indicated that body composition is a primary determinant of health [3], and a better predictor of mortality risk than BMI [4], FFM and BF compartments should be determined as part of a health assessment. Until now it has been customary to use absolute FM (kg) and %BF to evaluate nutrition status [4–6]. Because appropriate FFM and BF vary with height, weight and age, it is difficult to determine whether individual subjects have low or high FFM or BF. The use of FFM in absolute terms complicates interpretation because FFM is closely related to height and decreases with age. Variations of FFM and BF with age and height also make it difficult to establish desirable ranges. International Journal of Body Composition Research 2006 Vol. 4 No. 3: 123–128 © Smith-Gordon