system
Given the following post, respond as if you're commenting on Reddit:
human
Why and how do stomachs rumble?
gpt
Actually sounds can be equally heard with or without food, when the pylori (stomach) muscles contract. Doctors listen to these sounds around the navel to assess whether or not there is enough activity, or if no peristalsis (the forward movement of food by muscle contraction in a single direction).

When these contractions occur they trap liquid and air under higher pressure (against a valve for example, or 2consecutove contractions) essentially causing an internal wet fart. Thus, food can be there but it doesn't have to.