BACKGROUND: Obesity is frequently associated with metabolic and cardiovascular co-morbidities and high mortality rates. Besides, because of the increasingly recognized fact that conservative therapy for morbid obesity is associated with an almost 90-95% failure rate in the long term, and probably because of the development of laparoscopic surgery,the demand for bariatric surgery is increasing rapidly.The significant weight loss observed during the first 6-12 months after gastric banding is related to the severe food restriction, related hypercatabolism, and has a potential risk of mineral and vitamin deficiencies.The aim of this study was to evaluate the effects of gastric banding on total body composition, metabolic profile and nutritional status. METHODS: 31 women were studied with median age 36 years (range 25-52), body weight 118.6 kg (range 98-156), BMI 43.6 kg/m(2) (range 36-56 kg/m(2)), percentage of excess body weight (%EW) of 107% (range 72- 166%), waist 115 cm (range 98-132) and hip 138 cm (range 119-155). Total body composition was measured before, 6 and 12 months after laparoscopic gastric banding, using dual-energy x-ray absorptiometry. Metabolic and nutritional profile were evaluated before and 1, 3, 6, 9 and 12 months postoperatively. RESULTS: There was a 23.3% reduction of total body weight and 36.8% reduction of body fat. Unfortunately we also observed a reduction of Fat Free Mass (FFM) of 9.6%. In addition, the major determinants of weight loss were the initial body weight and abdominal distribution of fat mass. Reduction of FFM was positively correlated with the rapidity of weight loss. A significant improvement of glucidic profile was observed, with disappearance of impaired fasting glucose, and normalization of the values of triglycerides in all patients. The prevalence of the metabolic syndrome decreased from 89% in preoperative conditions to 15% 1 year after gastric banding. No major nutritional deficiencies was found following gastric banding. CONCLUSIONS: This prospective study suggests that the first 6 months postoperatively are crucial for weight loss and changes in body composition. Furthermore, the significant reduction of body weight is accompanied by an important improvement of biological abnormalities.