Oprah's favorite weight loss doctors, Michael Roizen and Mehmet Oz, would be proud of Los Angeles this weekend. In their most recent book, You: On A Diet, they say you should walk thirty minutes every day no matter what. "No excuses. It doesn't matter if you do this in one whole block or broken up into as many as three shorter sessions." Inspired by Franklin Ave's Wilshire Walk, Will Campbell from Metroblogging Los Angeles......