For the past year, many of the nation's chain restaurants have trumpeted their efforts to give consumers helpful details about the food they serve — from calories to carbs.

An unscientific spot check of some of the most popular suggests they do indeed offer a lot of information — from Ruby Tuesday's (search) 1,164-calorie Cuban panini to Subway's (search) 210-calorie Ham Deli sandwich.

The push to tell what those menu items will cost your waistline might be more than just helpfulness. The Food and Drug Administration and members of Congress have been considering whether to require such information from restaurants.

No doubt some people might be shocked to know that a 32-ounce McDonald's (search) vanilla shake has 1,110 calories — more than two Quarter Pounders (840 calories).

Early on, the Tennessee-based restaurant chain Ruby Tuesday was among the boldest, putting those daunting calorie, fat and carb counts right there next to that high-calorie panini. But by summer's end, those details were off the menu and put in a separate booklet.

Company officials insisted it was no effort to hide calories. They said they were just cutting down on expensive reprintings every time the chef decided to alter the menu.

Indeed, the six-page "Smart Eating Guide" was on every table during lunch at a Ruby Tuesday in Brentwood, Tenn., outside Nashville.

That Cuban panini's fat, carbs and fiber were revealed — along with a chart to help tally up the various salad bar choices.

An Applebee's (search) in Austin, Texas, offered less comprehensive details. It gave a breakdown on just a handful of selected entrees and appetizers. But it also listed Weight Watchers' "points" — crucial to folks who stick to that eating plan. The Sizzling Chicken Skillet, for instance, at 360 calories, 4 grams of fat, and 10 grams of fiber, carries just 7 points.

Customers looking for a carb count are out of luck, though.

And when a waiter was asked for nutritional details for the onion peels and horseradish dipping sauce, "We don't have any of that here" was the reply. The waiter returned with a Web site and phone number.

The experience was similar in Springfield, Mo., at TGI Friday's (search), which has teamed up with Atkins Nutritionals Inc. to cater to the low-carb crowd.

A separate section of the menu listed Atkins-approved foods, from appetizers to main courses, with net carb counts. The garlic chicken with mixed vegetables, for instance, has a mere 7 net carbs.

Diners were given no other guide for making healthy choices from among the other dishes.

The manager offered a toll-free number for TGI Friday's corporate office when asked for more information. A spokesman there said only Atkins' net carbs were listed for selected items.

"If chain restaurants can provide nutrition information on Web sites, they can put calorie numbers on their menus," says Margo Wootan, nutrition policy director for Center for Science in the Public Interest.

Sen. Tom Harkin, D-Iowa, and Rep. Rosa DeLauro, D-Conn., plan to reintroduce bills to require fast-food chains to list calorie counts on menu boards; they want table-service chains to list calories, fats, carbs and sodium on printed menus. The proposed legislation would affect only chains with 20 or more outlets.

Harken cites studies indicating some 75 percent of adults read food labels in the supermarket, and more than half of those said it caused them to change their minds about the foods they purchase.

But Subway sandwich shops don't need legislation as an incentive. Some locations take a full-frontal approach to nutrition data, starting before diners get in the door.

At a Subway in Concord, N.H., a sidewalk placard offered copies of a pamphlet with a dizzying array of data on virtually every sandwich, topping and condiment. (Those garlic almonds on your salad will cost you 80 calories.)

As you walk in the door, a sign admonishes: "Be good. Be heart smart."

Large wall-mounted menus above the workers making sandwiches repeat the message and highlight low-carb and low-fat options, including those that have earned Atkins' seal of approval.

The plastic takeout bag again reminds consumers that Subway has "seven subs with six grams of fat or less." A chart printed on the napkins lists nutrition data for all of them.

It was a different story at a Boston Market (search) in the New York suburb of Mamaroneck. A worker had to abandon the counter for six minutes to get a computer printout revealing calories and other details for the restaurant's tasty creamed spinach.

In fact, the food order was ready to go before the worker returned. She explained that "a long time ago" the restaurant had nutritional information posted, and that another Boston Market nearby did post it.

Once she provided it, the computer printout listed tremendous detail — calories, fat, saturated fat, protein, cholesterol, sodium, fiber and sugar. That tasty creamed spinach tallies 260 calories and 20 grams of fat, thanks to the added cream and cream cheese — details mentioned on one of the soft drink cups.

At a McDonald's in Springfield, there was no nutritional data on the menu board. When asked for help, however, the cashier immediately offered a paper placemat that broke down 67 items from salad dressings to desserts. She also pulled out two sheets with nutritional contents of breakfast and sandwiches without bread.

Wonder what a Big Mac (search) minus bun will do to your waistline? It's 380 calories, 30 fat grams, 11 carb grams, 19 protein grams and 760 milligrams of sodium. The bun adds 220 calories, 3 fat grams, 39 carbs and 340 milligrams of sodium.

A Burger King (search) across town had a large poster on the wall that broke down the contents of each food item. The only hitch was that it was mounted where customers pick up orders. It also had small print and was too high to be of much use to those shorter than 6 feet.

Asked if a printout was available, the cashier smiled, left and returned with the Web site.

"For nutrition information to be useful, it needs to be at the point of decision-making," Wootan said. "Few fast-food consumers want to lose their place in line to squint at a hard-to-read poster."