There are multiple traits you can get in Project Zomboid that will give you positive and negative traits during your zombie campaign. For those who want to start with a negative trait, Out of Shape is one of the better ones to choose.

Unlike many of the other traits you can give yourself to start out in Project Zomboid, the Out of Shape trait can actually go away. You have to work at it, though. If you don't want to work at it, the Out of Shape trait is here to stay, and you'll have to deal with the added consequences of trying to outrun the zombies, making them harder to fight.

The only way to remove the Out of Shape trait in Project Zomboid is to work on multiple exercises and increase your character's Fitness skills. An optimal way to increase your character's Fitness skills is to have them consistently work on and increase their Exercise Regularity, or you can do it naturally by having them run or fight zombies. However, constantly sprinting everywhere and hitting zombies will take more time.

Eventually, if you increase your Fitness skill and it gets above the negative two points you get for equipping it during Project Zomboid character creation, the trait disappears. Not many other traits do this in Project Zomboid, making it a preferred starting skill for any campaign.