Think it's time to make some healthy lifestyle adjustments? Dan Buettner, author of The Blue Zones: Lessons for Living Longer from the People Who’ve Lived the Longest, is right behind you. Buettner is crossing Iowa in a bus, attempting to change American towns into healthier places. "More than 40% of Americans smoked in the ’60s, and only 20 percent do now," he points out. "We can turn around our diet and lifestyle, too."