SAN FRANCISCO (MarketWatch) — Not sure what Alice Waters would have to say about them, but Wall Street is certainly heaping praise on McDonald’s and Chipotle for their latest contributions to the nation’s culinary landscape.

McDonald’s Corp. MCD, +0.37% , that mighty mélange of fast food, money and industry, turned up the heat in the third quarter with overall sales growth of 5%.

U.S. flags flutters in front of a sign for a McDonald's restaurant in Los Angeles. Reuters

That’s an amazing achievement, given the downbeat state of the economy. Or maybe it’s precisely because of the downbeat economy. Fancy additions to the menu have made dining at McDonald’s more acceptable to those who would, at least among friends, never admit to ordering from the expanded Dollar Menu. Hey, times are hard.

With these well-placed tweaks, McDonald’s managed last quarter to squeeze a 4.4% increase in sales from its established restaurants in the United States. That tops a 3.4% gain in same-store sales in Asia, which had been the big growth market for it over the past few years.

The improvement drove a 9% rise in net profit to $1.45 a share. Analysts, who typically don’t cut McDonald’s much slack, were expecting $1.43, so the “beat” was significant. McDonald’s shares promptly hit an all-time high of $92 a share at the open Friday and held the gain through much of the session, making it one of the biggest winners on the Dow. Read about McDonald's blowout quarter.

The numbers were even more impressive over at Chipotle Mexican Grill Inc. CMG, -1.41% , the popular burrito maker that McDonald’s spun off back in 2006, having bit off progressively larger stakes in Chipotle from 1998 onward. Obviously, McDonald’s didn’t send Chipotle into the fray unprepared. Whatever procurement, placement and management magic McDonald’s could offer went into the Chipotle recipe.

And it shows. Chipotle, which released its latest results late Thursday, saw its third-quarter profit jump 25% from a year ago. Read about Chipotle's third quarter.

There are a couple of ways to looks at both companies’ success. McDonald’s is recruiting customers from a downwardly mobile middle class. Chipotle, in giving fast-food an upscale feel, may well be appealing to much the same demographic. It might be selling high-end burritos, but let’s not forget — they’re still just burritos.

Where the two companies diverge is in their appeal to shareholders. McDonald’s continues to turn out solid results, backed by an equally solid dividend. It is a blue-chip stock with a global reach and operates with the kind of economies of scale only industrial behemoths achieve. It has a market cap of nearly $92.5 billion. It’s price-to-earnings ratio is 18.2.

Chipotle, on the other hand, has a market cap of $9.7 billion and a P/E ratio of (gulp) 54.5! Over the past year, its share price has rocketed 84%. It’s up over 500% since it went public. This is where fast food, food fads and stock bubbles are wrapped into one.

Chipotle shares again shot upward Friday — closing at an intraday high of $333.50, and within shouting distance of an all-time best — as investors savored its latest earnings.

Which raises the question: How long can this feeding frenzy last before Wall Street steps back and says, “It’s been amazing, but we think we’ve had enough.”

— Jim Jelter