Growth investing relies on a simple premise: Find great companies that will outperform over the long haul, outgrowing their premium valuations over time. This, of course, is easier said than done. In the video below, Fool contributor Daniel Sparks discusses a great way to tell the gold from the fool's gold. To illustrate, he takes a look at Whole Foods Market (WFM) and Panera Bread (PNRA).