It's about discipline.
Just like investing or anything else you commit your life to.
When you examine your day, do you find opportunities when you could have executed an action in such a way that leads you to your goal?
When I find a way to save twenty cents a day my driving 1 mph slower, that leads me to my goal. Does that .20 mean anything. No, but it is the pursuit of lowering costs and maintaining discipline.
I assume the same thing can be applied to being healthy. Try to find things you do that is not healthy and eliminate them. And find opportunities to do things you already do, but do them in a healthy way.