Minecraft wiki entry for Development_versions, associated text: High saturation no longer gives a fast regeneration boost.
Changed food eating speed from 32 game ticks (1.6 seconds) to 40 game ticks (2 seconds).
The player now naturally regenerates health when above a hunger level of 6 () instead of 18 ( × 9).
The player now naturally heals every 60 game ticks (3 seconds) instead of every 80 game ticks (4 seconds).
Natural healing now always drains food points.
Saturation is not used when healing damage, and is only relevant to other actions that drain the hunger bar.
The player can now sprint at any hunger value.