Changes in body fat: Measurements by neutron activation, densitometry and dual energy X-ray absorptiometry

The measurement of body fat in ten subjects (BMI from 22 to 43 kg/m(2)), and in particular the changes arising from a ketogenic diet, by the techniques of in vivo neutron activation analysis (NAA), densitometry (using two-and four-compartment models) by under water weighing (UWW) and dual energy X-ray absorptiometry (DXA) was compared. The association between techniques for the fat changes was' generally high (r = 0.70 to 0.98) and significant (p < 0.05). Assessment of agreement between DXA and the other techniques revealed discrepancies with significant slope and high association (r = -0.81 and -0.64). Whilst NAA and UWW appeared to measure similar changes, DXA underestimated small changes. (C) 1998 Elsevier Science Ltd. All rights reserved.