This study was performed to investigate the effects of a levan diet on the body fat accumulation and serum lipid composition of 29 Korean women over a period of up to 12 weeks (n = 13 for the control group, n = 16 for the levan group). The subjects ate an uncooked diet (6 g) with 400 ml of tap water twice a day. The mean body weight and height measurements of the subjects (levan group) at the outset were 66.0 +/- 8.8 kg and 156.7 +/- 5.3 cm, respectively. The subjects showed a significant reduction in weight, body fat mass, anthropometric measurements and skinfold thickness during the experimental period. The waist hip ratio (WHR) was 0.88 +/- 0.03 at the outset, and fell to 0.82 +/- 0.05 after 4 weeks. The intake of levan was also influenced on the levels of serum Fe, leptin, lipoprotein lipase, HDL-cholesterol, LDL-cholesterol, and triglyceride. The serum glucose levels were within the normal range during the experimental period. The initial serum triglyceride level was 121 mg/dl, but fell to 103 mg/dl after 4 weeks of levan supplementation. The current study demonstrates that a levan diet is effective in controlling weight, body fat, HDL-cholesterol, LDL-cholesterol, and triglyceride levels.