A method and system for estimating the visceral adipose tissue (VAT) mass or volume of a subject comprises performing a dual-energy X-ray scan of the subject; generating at least one image of the subject from the dual-energy X-ray scan; identifying a region of interest on the at least one image; dividing the region of interest into a plurality of sections; determining an outer transverse extent of a coelom or inner abdominal cavity of the subject; determining a subcutaneous adipose tissue (SAT) composition for each of the plurality of sections, wherein the SAT composition determination is restricted to an area directly anterior and posterior the coelom or inner abdominal cavity of the subject; and determining a VAT mass and/or volume for the region of interest based on the determined SAT composition for each of the plurality of section.