What does "Without padding one’s end zone" mean?

Solution 1:

Oishi-san, "your end zone" here refers to your average Super Bowl watcher's "end" area, which is to say your derriere, or your buttocks, or (in Japanese) o-shiri (お尻).

Snacking while watching the game is an American pastime, and as we all know, snacking puts on pounds. Often where you want them least. Like in your end zone.

Note: "End zone" is a pun, because the object of American football is to have one of your team carry the ball across the opponent's goal line into their end zone.

Solution 2:

This article refes to how to avoid putting on weight specifically in the 'butt' area. Padding is one of those English words with several meanings, but all refer to putting something on, filling something in. And padding has the connotation of something soft, which people often become when they put on the pounds. With regard to weight, we sometimes say;

He's got some padding on him. (Or), She's well-padded.