Mortal Flesh Is Weak

• WWizards of the Coast2010-06-15
  Official Ruling
  For a player’s life total to become a certain number that’s lower than their current life total, what actually happens is that the player loses the appropriate amount of life. For example, if the lowest life total among your opponents is 5 and another opponent has 12 life, this scheme’s ability will cause that player to lose 7 life. Abilities that interact with life loss will interact with this effect accordingly.

Rulings via Scryfall