In the 1970s, most pundits probably thought that John Mackey was crazy for thinking Whole Foods Market (NASDAQ:WFM) could ever become a force on the national food scene.  But decades later -- and with a stock that's up 2,600% since going public -- it's clear that Mackey was on to something.

The problem is, that "something" -- namely, a movement to educate yourself about where your food comes from -- has been so popular that it's attracting competition from all corners.  In fact, so far this year, Whole Foods' stock is down almost 30%, largely due to concerns about competition.

Though investing (as opposed to trading) means taking a years-long approach to buying and selling stocks, checking in periodically with one's holdings is important.  So what should investors be focused on, and what should they look for by year's end from Whole Foods?  Check out the slideshow below to find out.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool's board of directors. Brian Stoffel owns shares of Whole Foods Market. The Motley Fool recommends and owns shares of Whole Foods Market. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.