Health Regeneration

Overhaul of the healing system using the Combat Test Snapshots mechanic. (No more fast healing from saturation, regen down to 7 hunger, faster regen, ...)
When hit 3 times in rapid succession you get the Injured effect that slows down the health regeneration, instead, when you eat from low hunger, you gain the Well Fed effect that speeds up health regen.

Food Consuming

Food now restores 63% of the normal hunger points (e.g. a Cooked Porkchop would give 5 hunger instead of 8).
Food is consumed slower based on hunger + saturation given. Low nourishment foods can be consumed faster than vanilla.
Makes Potions, Milk and Honey be consumed faster like the Combat Test Snapshots
If eating / drinking and you get hit by a mob (directly or indirectly), you'll stop eating/drinking, like in Combat Test Snapshots.

Exhaustion increase

By default Minecraft adds 0.005 exhaustion per block break. (Exhaustion = loosing hunger)
With this feature instead exhaustion is given whenever the player is breaking a block, meaning that the more time taken to break blocks, the more hunger is consumed.

Since MC 1.18+ you get passive exhaustion, 0.005 each second.
Also the hunger effect amplifies exhaustion gain by 100% per level.