It’s only ever you in there. They just put away the props, take off the makeup, and get ready to argue about which color of pants should go with those shoes your spouse hates but you like so much.

Burping and farting are tiny, but if we’re talking gasses and changing weight, the vast majority of the mass you lose from fat when you lose weight actually comes out in your breath.

Also not a doctor but glucometers can be cheap, not that scary, and answer exactly this question.