Most reflux during the day occurs after meals. This reflux probably is due to transient LES relaxations that are caused by distention of the stomach with food. A minority of patients with GERD, about 20%, has been found to have stomachs that empty abnormally slowly after a meal. The slower emptying of the stomach prolongs the distention of the stomach with food after meals. Therefore, the slower emptying prolongs the period of time during which reflux is more likely to occur.