The subjects were studied before and at 3, 6 and 12 months after the operation. All the patients underwent an oral glucose tolerance test (OGTT) with 75 g glucose, preoperatively. In addition, venous blood was collected after an overnight 12 hour fast and 30, 60 and 120 min after the administration of a 300 kcal mixed meal.The meal was consumed in ten minutes and consisted of 18% protein, 55% carbohydrate and 27% fat (Resource energy drink, Nestle Nutrition, France). Plasma levels of PYY, GLP-1, ghrelin and insulin were determined at every time point of the study. All patients underwent complete clinical evaluation during follow-up including nutritional, behavioral and anthropometric parameters. Visual analogue scales (VAS) were used to measure hunger, nausea, fullness and aversion to food, before and 30, 60 and 120 min after the consumption of the meal. Weight loss evaluation was based on postope¬rative body weight, body mass index (BMI) and % excess weight loss (EWL %).