I get gassy and bloated when i get really hungry (like gnawing hunger). what's going on?

Signals are sent from the brain to the stomach cells to produce hydrochloric acid in order to prepare for digestion. The production of acid causes gas to build up in the empty stomach (bloating) and acid starts to act on your stomach walls. The stomach wall muscle will protest by physically cramping (bowel noises you hear from a growling empty stomach are a result of all these factors).