Hands on your belly, breathe so that it moves, and listen. A gurgle down there is a real sign that you have stopped bracing.

What the research says

A review of C fibre touch describes how slow gentle stroking of hairy skin activates a separate class of nerve fibres that feed into the brain's picture of the body's internal condition, rather than into fine touch discrimination. So there is a real channel by which gentle contact updates your sense of your own insides. That work is about skin rather than gut, and it does not test stomach noises as a marker of anything.

Strength of evidence: one line of research. A single study, or a theoretical account.