Weight Watchers' profits have been slim, as competition from free weight loss apps rises. CNN's Richard Quest explains. <script type='text/javascript' src='http://i.cdn.turner.com/cnn/van/resources/scripts/van-widgets.js'></script> <div data-cnnvansinglewidget data-affiliate='gantdaily' data-videoid='business/2015/03/02/pkg-qmb-weight-watchers-skinny-bottom-line.cnn' data-size='auto' data-autostart='true'></div>