in the early game you don't have high enough skill to take damage, unless you're jumping off cliffs and hills.
by the time your skill increase to the level that you take damage from jumping you should have food (ideally in all 3 slots). which among other things like increasing health pool gives you regeneration.

also..random fact: falling damage is capped at 100. you can't die if you have 101hp or more. (unless there are also other sources of damage like fire\poison or enemies