Say, supposedly, during Mass, you have a piece of food stuck in your teeth, and after some tongue-pushing, it comes out and you swallow it. Since you technically ate something (and Communion is probably within an hour), would you still be permitted to receive the Eucharist?
Digestion begins in the mouth. The food was consumed previously. Swallowing such partially digested food does not constitute eating and does not break the fast.
Fr. Vincent Serpa, O.P.