There are various potential causes of chronic acid reflux. Most of these are due to the dysfunction of the esophageal muscles. Typically, there is a valve that allows food into the stomach but closes after swallowing. A significant cause of dysfunction in this valve is obesity, creating unnecessary upward pressure on stomach, pushing food and gastric juices back into the esophagus. Dietary habits including spicy, high-fat or highly-acidic foods can also create an environment conducive to acid reflux.

Hiatal hernias can also cause the upper portion of the summit to push into the diaphragm, causing acid to reflux. Since this is a common issue with those who are overweight, hiatal hernias are often repaired secondarily during weight loss surgery, for example sleeve gastrectomy and gastric bypass.