Nine obese males of Scandinavian origin were examined with a multiscan (n = 22) computerized tomography (CT) technique before and after a small weight reduction (4.4 kg). The total adipose tissue (AT) volume was reduced by 2.6 litres. Expressed as a percentage of initial depot volume, there were significant reductions (P < 0.02) in the AT depots of viscera (9.6%), upper limbs (7.0%), subcutaneous trunk (6.0%) and lower limbs (4.9%), while the AT of head and neck (1.9%) did not decrease significantly (P = 0.08). These results indicated a changed fat patterning and evidence for this was obtained by expressing the AT volume of each depot as a percentage of the total AT volume both before and after the weight reduction. Visceral AT constituted 21.7% of the total AT before and 20.9% after weight reduction. Thus, the fraction of AT in viscera was changed by -0.8 +/- 0.9% units which was significantly different from the change in leg AT (+0.5 +/- 1.1% units) (P < 0.02) and tended to be different from the change of subcutaneous AT (+0.2 +/- 1.0% units) (P < 0.07). Thus, the AT distribution was changed in a favourable direction by weight reduction. Changes in visceral/total AT area ratios of different trunk scans were not consistent and, in a stricter sense, fat patterning cannot be studied with area determinations since AT areas cannot be expressed as fractions of the total AT volume.