She says she trained herself not to by sheer willpower

Does she burp a lot instead? Maybe she's pumping it back up the other way. Kind of like how railguns vs blasters work lore-wise in EVE Online:

Consists of two components: a shell of titanium and a core of antimatter atoms suspended in plasma state. Railguns launch the shell directly, while particle blasters pump the plasma into a cyclotron and process the plasma into a bolt that is then fired.