"Of course, while history may be a good indicator of the strengths of a company, the future's what investors are looking for." So said Alyce Lomax just a few moments ago.

No question, Alyce. And that's precisely why Whole Foods (NYSE:WFMI) is such a dangerous stock.

Premium sometimes just means "expensive"
What I mean is that sometimes an expensive P/E ratio really is indicative of a stock that's going nowhere. How do I know? I screened for stocks that, like Whole Foods, had a trailing 12-month P/E of at least 60 but which had also declined by 20% or more in the past 52 weeks. The search revealed some impressive names:

Company TTM P/E Forward P/E TTM Return
63.67 24.09 (20.5%)
Electronic Arts (NASDAQ:ERTS) 63.03 46.75 (25.2%)
Four Seasons Hotels (NYSE:FS) 73.58 36.89 (21.7%)
Source: Yahoo! Finance

Hyping the future
That's not to say Whole Foods is on par with any of these businesses. For now, the green grocer is far better, and that's why it can get away with charging a premium both for its products and its stock. But it may not stay that way. And, really, weren't Comcast, Electronic Arts, and Four Seasons also all great businesses at one time? You bet.

Remember, too, that Whole Foods depends on its premium brand to maintain pricing power. A hiccup in quality arising from a chaotic supply chain could quickly erase some of that goodwill and send previously committed customers heading for the exits. After all, this is the company that Californians tend to call "Whole Paycheck," according to BusinessWeek.

Finally, there's that extra $2 billion that made its way into Mackey's 2010 projections recently. I'd like to know: What drove the revision? According to press reports, it's a belief that Whole Foods can open 25 to 30 new stores per year. OK, but that's a huge change. Whole Foods opened 15 stores in 2005 and hadn't opened more than 12 since 2001, according the company's most recent 10-K annual filing.

Growth is never infinite
Alyce, you're still very much one of my fave Fools, but the fact is that Mackey is asking investors to believe that he can do what he's never done before. That would be fine if the stock were cheap, but it isn't. It trades for three times its long-term projected earnings growth rate.

I've no doubt that Whole Foods is a truly wonderful, important business. But the market is littered with wonderful, cash-rich businesses that have made for poor stocks over extended periods. Inside Value pick Microsoft (NASDAQ:MSFT) is one, and surely there are dozens of others. Will Whole Foods join that list? I've no idea, but I'm not about to pay up to find out.

Whole Foods and Electronic Arts are Motley Fool Stock Advisor selections. Ask us for a30-day all-access passto find out which other stocks are helping David and Tom Gardner wallop the market by more than 25% each. Orsubscribeorrenewnow, and we'll throw inStocks 2006, which features our analysts' best picks for the year ahead. All you have to lose is the prospect of greater returns.

Think you're done with the Duel? You're not! Go back and read the other three arguments, and then vote for a winner.

Fool contributorTim Beyerseats loads of organic food. But Wild Oats is closer to his house than Whole Foods is. Tim didn't own shares in any of the companies mentioned in this story at the time of publication. You can find out what is in his portfolio by checking Tim's Foolprofile. The Motley Fool has an ironcladdisclosure policy.