Body composition measurements provide essential information for assessing and monitoring nutrition state.1 Some researchers use underwater weighing or potassium counting as reference methods for total body composition. However, these methods assume a constant density and potassium content of lean body mass (LBM), which may not be true, and measure only two compartments, fat (FM) and LBM.2 A multicompartment approach combining different technologies that measure bone, mineral, muscle and water is preferable and currently considered the gold standard.3 Nevertheless, its high costs, long duration, and the potential intolerance of patients limit its use in clinical routine. Thus, other methods, especially dual-energy x-ray absorptiometry (DXA), have been investigated. Although the original purpose of DXA was to determine bone mineral density, recent devices measure total and regional body composition of three compartments, fat and lean soft tissues and bone mineral.4 This editorial focuses on the advantages and limitations of DXA and the differences in total and regional body compositions. In this article, the combination of lean soft tissue and bone mineral is referred to as LBM.