Recent studies have demonstrated an association between the pattern of body fat distribution and the occurrence of cardiovascular risk factors. In this study, we evaluated changes in body fat distribution as defined by several anthropometric criteria during a six week weight reduction programme in 110 obese adolescent girls (mean age 15.2 +/- 0.4 years). The standardized regimen included a mixed diet of 1032 kcal/day and a daily exercise programme of 1-2 h duration. The mean weight loss was 8.6 +/- 2.8 kg, decreasing the body mass index (BMI) from 31.4 +/- 4.7 to 28.2 +/- 4.9 kg/m2 (P < 0.01). The reduction in body weight was accompanied by a significant decrease in the waist-to-hip ratio (WHR) from 0.86 +/- 0.06 to 0.81 +/- 0.05 (P < 0.01). The initial WHR was correlated with the degree of weight loss independent of the initial weight (r = 0.34, P < 0.001). Categorized according to the waist-to-hip ratio girls in the upper tertile (WHR > 0.88) lost significantly more weight than girls in the lower tertile (WHR < 0.80) (9.8 +/- 2.7 vs. 6.8 +/- 2.5 kg, P < 0.01). These findings suggest that girls with an abdominal type of obesity benefit more from a weight reduction programme than girls with a gluteal-femoral type of obesity.