You can buy titanium sporks and AR-15s and hatchets until the cows come home, but unless you can move your own butt along with all that tactical gear, you're just the next snack for a zombie.
Prior to societal collapse, you need to train your body to do at least this:
1) Run 3 miles at a whack, 2-3x per week
2) Run 1x off-road (minimum)
3) Do my daily workout.
This will train your nervous system, muscles, cardiovascular system, and bone structure to make the adaptations NOW that you'll need THEN.
You'll also tap into the energy systems you need to burn extra fat.
Do it without stopping, no matter how slow or ugly it looks. And do it without whining, because it's free, and it's awesome.