You know, walking is very good exercise. If everyone did enough, we might be able to claim victory in the battle of the bulge. But what's an effective and memorable manner in which to communicate this idea? Well, how about this:
Fozzie Bear speaks to the camera at a comedy club, saying: "What's an effective way to stay fit? Walka Walka!" and then he walks back and forth to demonstrate. (His catchphrase is: "Wocka Wocka.") Then we could hear the Surgeon General recommend walking a certain distance per day or week to maintain fitness.
(Yes, it's silly; but it's also memorable.)