O.P., if you have any health issues like diabetes or any other blood sugar issues, then you may not have a choice. I have to eat breakfast when I get up or it will mess with my blood sugar. I don’t need to be passing out while driving to church. That being said, get up earlier so that you don’t need to worry about it, I started doing that (harder to do when I have to work on Saturday, I end up being really tired Sunday morn), then eat.
If you are worried enough time has not elapsed then don’t receive the Eucharist that Sunday, do it next.
I take Communion so serious that if I believe I may have committed a mortal sin and not have been to confession yet, I will pass. I have a particular sin I struggle with and usually fall short so more often than not I don’t receive because I don’t wan’t to receive unworthy. There is no shame in not receiving, if you feel you are not in a state to do so.
My understanding as to why the Church does this, as it was explained to me, is so that anything you ate is completely digested and will not mix with the Eucharist before that is completely digested, since the Eucharist is Jesus.