Obesity is considered a primary risk factor for cardiovascular disease and related mortality. The current study aimed to investigate the efficacy of minimal invasive gastric banding (GB) surgery for reducing caloric intake in morbid obesity, and to analyze the effects of weight loss on body composition and metabolic and psychosocial outcomes. Twenty-six adult severely obese patients (mean body mass index [BMI], 48.1 kg/m(2); range, 42 to 56) underwent adjustable silicone laparoscopic GB. Nine additional obese patients who declined surgery were treated with metformin (2 g daily) and served as a small additional group (BMI, 50.5 kg/m(2); range, 41 to 68). Presurgery and 17 +/- 2.2 months postoperatively, body composition (fat mass [FM], lean body mass [LBM], body water) and serum parameters (lipids, glucose, thyrotropin-stimulating hormone [TSH]) were determined. Quality of life (QoL) was evaluated by a standardized self-rating questionnaire (Short Form-36 [SF-36]), and supplemented by measures of physical complaints and psychological distress. After GB, weight loss was 21 +/- 14.9 kg (14%, P <.001). It was associated with a decrease in FM by 14 +/- 8.6 kg (18%, P <.001), LBM by 4 +/- 2.7 kg (5%, P <.001), body water by 4 +/- 3.4 L (7%, P <.01), systolic blood pressure by 16 +/- 26.3 mm Hg (10%, P <.05), total cholesterol by 0.69 +/- 1.29 mmol/L (12%, P <.05), and low-density lipoprotein cholesterol (LDL-C) by 0.38 +/- 0.39 mmol/L (10%, P <.05). Highly significant interactions between surgery and time were noted for weight (P <.005), BMI (P <.005), and FM (P <.007, analysis of variance [ANOVA]). Preoperatively, 14 of 26 patients (54%) had high fasting blood sugar levels (type 2 diabetics) and 11 (42%) had impaired glucose tolerance, whereas postoperatively, for baseline glucose levels a trend to decrease was noted. Neither malabsorption nor anemia was observed. QoL improved after GB; in particular, physical functioning and well being increased (P <.01), and somatic complaints (eg, dyspnea and heart complaints, pain in legs and arms) markedly decreased (P =.008). In the metformin group, neither relevant weight loss nor a significant decrease of biochemical values was observed. Minimal invasive GB is a successful therapeutic tool for reducing FM in morbidly obese patients. Weight loss resulted in improved metabolic parameters, suggesting a lowered atherogenic risk.