Well I think you have that backwards, most people concern themselves with the former because they are the easiest to address. It's very easy to just eat less and buy healthier food. Getting your running shoes on and going for a run when you're out of shape and overweight is extremely hard for most people in that category.

That's certainly true, and nothing wrong with doing the "easiest" first, but it's interesting that people get so focused on such small changes in risk all the while ignoring the big ones.