From what to eat to how much to exercise, Elizabeth Cohen explains what you really need to do to lose weight. <script type='text/javascript' src='http://z.cdn.turner.com/cnn/van/resources/scripts/van-widgets.js'></script> <div data-cnnvansinglewidget data-affiliate='gantdaily' data-videoid='health/2014/09/26/the-keys-to-losing-weight-elizabeth-cohen-orig-jtb.cnn' data-size='auto' data-autostart='true'></div>