We don't walk. We overeat because we've made it easy to overeat. We have fast-food joints on every corner. By the way the 'we' is all of us. It's not the government. It's all of us doing this together.
As told in Friendship with God if we simply decided to believe and act as if first we're all one and second life is eternal it would render virtually everything we've done all our lives pointless.
