Acid reflux occurs when there is acid backflow from the stomach into the esophagus. This happens commonly but can cause complications or troublesome symptoms, such as heartburn.One reason this happens is that the lower esophageal sphincter (LES) is weakened or damaged. Normally the LES closes to prevent food in the stomach from moving up into the esophagus.The foods you eat affect the amount of acid your stomach produces. Eating the right kinds of...