It’s not really killing him — it’s doing him a lot of good (although it is a big time outlay)! A mile takes about 15 to 20 minutes to walk, once you’ve got some practice (which, at his rate, he definitely has), and it doesn’t require much in the way of specialized clothing, as long as your shoes are reasonably sensible, so it’s a simple way to tuck in a bit of exercise. If you’re wondering where to start, adding in a walk like this 2 or even 3 times a day is a terrific plan.
The best part of this character’s plan is associating his exercise with something he is doing anyway — having a meal. This technique is called “anchoring,” and it works best when you anchor your new habit to something you do predictably, at least as often as you want to do the new behavior. For example, taking the stairs instead of the elevator may be impractical every single time, but one way to begin is to take the stairs when you first get to work and when you come back from lunch.
Learn more about anchoring, along with tips for choosing good starting points (really small things that are so easy there’s no reason to skip ’em), at BJ Fogg’s Tiny Habits project.