Source: this video by Dr Greger.
An excerpt from this video by Dr Greger from which the above image is borrowed:
"Hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux up into the esophagus and throat. It affects more than 1 in 5 American adults. In contrast, in rural African communities who were eating their traditional plant-based diets, it wasn't 1 in 5; it was closer to one in a thousand — almost unheard of. It's almost peculiar to those who consume Western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools; three or four times the volume of Westerners."
Hiatal Hernia, GERD and Acid Reflux are inter-related. A separate article contains videos for Acid Reflux and GERD. Below are videos that focus on the pressure-related aspects of Hiatal Hernia.
(4 mins) Transcript. Summary: "Straining at stool over time may force part of the stomach up into the chest, contributing to GERD acid reflux disease. This may explain why hiatal hernia is extremely rare among populations eating high-fiber diets."
An insightful video by Dr Greger in simple English.
(6 mins) Transcript. Pressure is not the only cause for triggering GERD; other factors (dietary in nature) also contribute. Additional articles that explain:
(2017, article by Dr Greger) Best Foods for Acid Reflux.
(2017, article by Dr Greger) Treating the Root Cause of Acid Reflux.
(2017, research paper) This research paper reported that 63% of GERD patients who adopted WFPB (with 5% to 10% of calories allowed from animal products) showed significant improvement vs 54% of GERD patients using standard medical treatment: