Sandvich

The sandvich is a lunchbox available to the heavy from all sources from the beginning of the game. Each use of the sandvich heals 1000 hp to the player. After use the sandvich takes 6 seconds to "reload". It would be able to be used once every 0.1 seconds if it had the magazine capacity.

Strategy
Mandarbmax says: Not as good a backup as a melee weapon if you ask me, but if you do want to use it, put a passive reload addon on it.

NoodleCupDetective says: I personally find this a great backup item that can save you in hard times. It fully heals you when used and feels necessary when you get to very high distances since it becomes harder to get healing from the cart or picking up medkits. However, make sure that you've got a primary weapon with at least ammo leech or high ammo capacity, since having the sandvich means you'll only be able to carry a single weapon. It's also possible to carry 2 weapons and only pick up the sandvich to quickly heal and then switching back to your weapon, but that only works if there's a sandvich on the ground nearby.