Sprint and hp with hunger

How would I make it so a player would not loose any hp and would still be able to sprint when they have no hunger?

For not loosing hp, I was thinking of using the player hp event if there is one and checking to see if there hunger is bellow 20 and cancel the event if so but I would think it would cause conflicts.

As for the sprint issue, I can't think of a way to do that, any suggestions?