Tim and Nina Zagat, the couple behind the wildly successful Zagat guides, argued yesterday in the Wall Street Journal that the restaurant biz will survive the economic downtown (can we call it a recession yet?). Their argument was forcefully made, based on historical data, tax laws, and social trends. But they overlooked one important factor: the rising cost of ingredients, all sorts of ingredients, from flour to oil.

In other words, people are eating out less often, and restaurateurs are paying higher prices. These two trends cannot coexist without some sort of fall out. Jeffrey Buben, owner and executive chef of Bistro Bis and Vidalia, told me recently, “It’s when you have inflation on the other end, that’s what clobbers you.”

Granted, Buben works the high-end side of the restaurant equation, but rising food costs (not to mention rising rents) affect everyone, not just fine-dining owners. I fear this economic great storm will be much nastier than previous ones, and the Zagats should have addressed it.