Obesity increases the risk of gastroesophageal reflux disease (GERD). The majority of the reflux attacks occur postprandially. The influence of the speed of food intake on gastroesophageal reflux events is unclear in obese patients. To determine the influence of the speed of food intake on intraesophageal reflux events in obese patients with and without GERD. A total of 26 obese female patients were recruited. The patients underwent esophageal manometry to evaluate the upper limit of the lower esophageal sphincter and subsequently placement of a Multichannel intraluminal impedance-pH (MII-pH) catheter. All patients were asked to eat the same standard meal (double cheeseburger, 1 banana, 100 g yogurt and 200 mL water; total energy value, 744 kcal; 37.6% carbohydrates, 21.2% proteins and 41.2% lipids) within 5 or 30 minutes under observation in a random order on two consecutive days. All reflux episodes over a 3-hour postprandial period were manually analyzed and compared. The mean age was 46 +/- 12 (18-66) years. The mean body mass index (BMI) was 39.9 +/- 8.4 kg/m(2). There was no difference between the fast- and slow-eating group in the number of refluxes within the 3-postprandial hours. The patients were divided into 2 groups according to the 24-hour MII-pH monitoring results, that is, 16 subjects with normal MII-pH monitoring and 10 patients with pathologic MII-pH monitoring. There was no effect of the speed of food intake in either the patients with or without GERD. In contrast to the general belief, this study suggested that the speed of food intake does not influence the number of refluxes in obese female patients with or without GERD.