The bone density fractionation method is a potential palaeodietary tool in tracing lifetime dietary changes as well as separating diagenetically altered fractions. This paper presents a workable bone density fractionation method that uses a devised mathematical model and the particle size distribution. Different grinding methods, i.e., a Spex $LN_2$ mill, a Disc mill and a Micronising mill, were used to reduce archaeological bone particles to an appropriate size range, which was then analyzed by a Laser particle sizer. It was found that density profiles are in good agreement with the diagenetic parameters, and with their stable isotope results.