Ask HN: How do you hack fitness ?

How do you manage to stay fit ? I am moderately fit, but more often than not, I lose motivation to go run everyday or workout / eat healthy food, and so it turns into a two step forward, one backward story.

This post [How to Push Past the Pain, as the Champions Do / http://news.ycombinator.com/item?id=1806944] a couple of weeks ago, re-inspired me to pick up and add some more discipline to my daily habits by changing my thought process a little, and on a similar note, I would love to hear about how do you manage to stay fit, and what thought process, and routine(if any) helps you get there ?

Thanks.