In the last year, a few dozen chefs have come to Swedesboro, N.J., to the test kitchen of Rastelli Foods, a wholesaler based near Philadelphia, in search of tips about how to trim portions - preferably in ways that diners won't notice.

Like many in this business, Rastelli has developed an impressive bag of tricks, and one recent morning staff consultant John Roehm shared a few of them with the owner of Conley Ward's Steakhouse, a restaurant in Wilmington, Del. Roehm focused on the chops, which will soon be downsized in subtle ways, but he's got an idea about the shrimp cocktail, too.

"What you do is skewer the shrimp before you boil them," Roehm says. "It straightens them out so that when you serve them, they look bigger. Now you can buy a smaller, less expensive shrimp."

Pinched by soaring food costs on the one hand and a recession-fearing public on the other, the restaurant industry is getting crafty. Chefs are tinkering with recipes, swapping out expensive ingredients for cheaper ones. Managers are using behavioral science research to rejigger menus - putting high-profit items in the top right-hand corner, for instance, where diners tend to look first.

And many restaurants are putting the great American portion - a monstrosity by the standards of international cuisine - on a diet, as surreptitiously as possible. Lots of restaurants are buying smaller plates to make the reduced servings look just as large, or lighter silverware so that even if there are fewer bites per serving, each bite feels heavier than usual on the fork. A la carte portions of high-priced dishes - steaks, for example - are getting pared back and surrounded by low-cost starches and vegetables.

"We've advised a lot of clients to switch from an eight-ounce filet to two three-ounce filets," says Rastelli Foods owner Ray Rastelli, who sells to 6,000 restaurants in the New Jersey, New York and Delaware area. "They reduce their cost by 25 percent and they change the plate presentation, adding some strategically placed accouterments. It looks like more food and it actually costs less."

Some restaurants aren't bothering with the sleight of hand. At Lucky Devils in Hollywood, the toasted pecan shake recently went from 18 ounces to 12 ounces, though the price didn't budge. At the Plumsted Grill in Cream Ridge, N.J., the filet mignon recently went from a 10-ounce to an eight-ounce portion.

"We also bought more small plates," says Plumsted co-owner Stacy Maul. "Our chefs were using these large platters for dishes like the chicken marsala, and they felt like it didn't look right unless the whole plate was covered. You give them smaller plates, they cook less food."

The science of skimping

Fret not, gluttons. There is little risk that portion shrinkage will cause anyone to lose weight anytime soon. That's because the point isn't to slim us down or lower our cholesterol. It's to save money in a business that many owners and consultants think is already in recession. A recent National Restaurant Association survey found that 46 percent of members reported declines in traffic in February over the previous month, not to mention "a record-low reading in restaurant operators' outlook and expectations." Smart owners, of course, have always carefully watched their costs, but when every bill comes with a "gasoline-price surcharge" and fewer people are walking through the door, it's hocus-pocus time.

The risk is that patrons will notice and get annoyed. (One Lucky Devils regular recently fumed online that the restaurant had "done something unforgivable. They have toyed with the toasted pecan shake.") A lot of restaurants prefer to charge more rather than fiddle with the food, on the theory that customers think of menu prices the same way that drivers think of a gallon of gas - they hate to see it get more expensive, but don't blame the gas station when it does.

But eating out is optional in a way that driving isn't, and there's only so much that a typical customer is willing to pay for a plate of fried calamari. And though risky, the financial upside to smaller portions is greater for a restaurant than you might think.

Take that 10-ounce filet mignon. At $20 per pound, it costs $1.25 per ounce. Start buying eight-ounce filets from your supplier instead and you spend $2.50 less per dish. A restaurant that sells a modest 100 filets a week will save $13,000 a year on that item alone.

Move enough entrees, and even pennies start to matter. Two months ago, the Lobster House in Cape May, N.J., changed the recipe for a flounder dish, getting rid of a vodka sauce that cost 70 cents per serving in favor of an assortment of vegetables with garlic seasoning, which cost about a third as much.

"We're the 14th-largest-grossing restaurant in the country," says John Thompson, a Lobster House purchasing agent. "Changes like that add up."