Here's a quick pop quiz for today's healthy fast-food consumer: Which has fewer calories -- a McDonald's Premium Crispy Chicken Club Sandwich or a Big Mac?
The answer: the Big Mac at 540 calories, compared to 630 for the chicken sandwich.
How about a Dunkin' Donuts glazed doughnut versus a plain bagel? The doughnut wins with 220 calories compared to 330 for the bagel.
Most people don't know that, especially when standing in front of the cash register about to order.
But that soon could change. Four states -- California, Maine, Massachusetts and Oregon -- soon will require chain restaurants to post calories on their menus. Another 14 considered similar legislation this year, according to the National Conference of State Legislatures, and a bill is working its way through Congress to require such disclosures nationally.
New York City was the first in the nation, in July 2008, to require calories on menus at chain restaurants.
Starbucks customer D.J. Martin, 29, said sometimes he'll splurge on a sausage, egg and cheese biscuit -- 500 calories -- but generally, seeing the calorie counts at the store helps convince him to avoid the chain's baked goods and stick to fruit and artificially-sweetened coffee.
"I just feel healthier," Martin said.
But not everybody feels that way.
Just because diners want to be conscious of calorie counts, it doesn't mean they always will be.
Maryanne McGarry, 63, and Dorothy Daly, 64, said they generally pay attention to calorie counts on New York City restaurant menus.
"Sometimes you learn that salads are worse than they are," Daly said.
But during a recent visit to an Olive Garden restaurant in New York City's Manhattan borough, the two threw caution to the wind: They had a craving for the restaurant's soup, salad and breadsticks combo meal, and calorie counts weren't going to get in their way. They didn't check the calorie counts on their meals.
"Don't tell us," Daly pleaded to an ABC News reporter.
For the record, a garden fresh salad with dressing, minestrone soup and three breadsticks amount to a total of 900 calories.
We won't tell them if you don't.
But even if all customers don't look at the calorie counts, some will -- and restaurants already have started to respond.
Starbucks cut the number of calories in its blueberry muffins by 80 calories, according to Margo G. Wootan, nutrition policy director at the Center for Science in the Public Interest and a leading advocate for so-called menu labeling.
McDonald's large french fries went down 70 calories, Wootan said, and Cosi switched to low-fat mayonnaise on its club sandwich, dropping the calorie count from 800 to 450.
(A report last year done for several Scripps television stations found that in eight cities across the country, the posted number of calories didn't always match the actual amount in the food as measured by lab technicians.)
Americans consume about a third of their calories when eating out, Wootan said. At restaurants, she added, "portion sizes are so big and the calorie count is so high" that picking wisely can have a major impact.
"From a split-second decision," Wootan said, "people can cut hundreds to even 1,000 calories from their diet."
There have not yet been any comprehensive studies about the year-long impact on New York restaurants thanks to the new menu law, but Wootan said it appears that customers are happy and business is holding steady at restaurants. (Watchers also point out that a fall-off in business because of the recession makes this year especially difficult to assess.)
"People say they are still eating out, they are just changing the way they order," Wootan said.
The industry has signed on to the national legislation in part because in New York, "they saw the sky didn't fall down," she added.
The National Restaurant Association has signed on to a compromise bill now moving through the Senate as part of the health care reform package. Chains with at least 20 locations nationally would have to post calories on their menus and menu boards.
The industry likes the bill because it would create one uniform standard in all jurisdictions and prohibit states and individual cities from imposing stricter restrictions, according to Beth Johnson, executive vice president of public affairs at the association.
"We are very supportive of menu labeling," Johnson said. "We very much hope to see that move forward."
Marion Nestle, a professor of nutrition, food studies and public health at New York University, said that companies have made big changes to the size of their products.
"There's just no question about it," she said.
She said most people think the calorie disclosure is wonderful. A few people complain they don't want the government regulating everything in their lives, but "they really don't want to hear what they don't want to hear."
The real problem though, Nestle said, is that people don't have an idea of how many calories they should be eating.
The typical middle-aged male is recommended to consume about 2,500 calories a day to be healthy, according to the U.S. Department of Health and Human Services. But consider this: Chili's Big Mouth Bites -- four mini bacon cheeseburgers served on a plate with french fries, onion strings and jalapeno ranch dipping sauce -- amounts to 2,350 calories on its own. Wash that down with a large soda, and you are already over the recommended daily intake.
What is unclear is if knowing that information matters to consumers. We might know that a meal is unhealthy but will order it anyway. Or some people would just rather live in blissful ignorance.
Health officials hope that most people will start making wiser decisions.
The calorie counts can lead consumers to some surprising epiphanies.
For instance, fish is widely praised for its health benefits but, at Applebee's, calorie counters might be better off choosing steak. The restaurant's Blackened Tilapia Sandwich consists of 1,210 calories, while its 10-ounce Bourbon Street steak weighs in a just 600 calories. Even with a side of mashed potatoes and vegetables, the steak dish is still under 1,000 calories.
At the Olive Garden, meat-lovers may be heartened to know that, calorie-wise, anyway, they won't be hurting much if they choose the chain's cheese ravioli with meat sauce over cheese ravioli with marina sauce. At 610 calories, the meat sauce dish is just 80 calories more than the marinara dish, according to the restaurant's menu. (Another twist? Both entrees contain fewer calories than the restaurant's grilled chicken Caesar salad, which has 850 calories.)
The meat versus meatless distinction is more stark, however, when you compare two personal pan pizzas from Pizza Hut. The chain's cheese-only, six-inch pie has 590 calories, while its meat-lover's pie contains 850.
At Starbucks, the muffin stats may mystify some: The chain's low-fat raspberry sunshine muffin has 340 calories, just 20 less than its blueberry muffin, which bears no "low-fat" distinction in its name.
There's no mistaking, however, the difference between a plain coffee and one of Starbucks' blended drinks: A 16-ounce coffee with milk is 110 calories, while a caffe vanilla frappuccino -- a vanilla-and-coffee drink -- of the same size is 310 calories. Add whipped cream, and the calorie count rises to 430.
Roshawn Boyce, 38, went out to Applebee's for lunch with two friends yesterday, where, she said, the women read the calorie counts with dismay.
"We do care about calories, but we hate the fact that [a meal] is so many calories," she said.
The calorie information on the Applebee's menu, Boyce said, helped her plan her meal. She chose the restaurant's crispy orange chicken bowl, a chicken-and-rice entree. But, because the meal contained 1,880 calories, Boyce decided to finish only half the dish and save the rest for diner.
Boyce said she hopes that restaurants across the country add calorie counts to their menus. It might have come in handy to her, she said, on a recent trip to New Orleans.
"I really went out of control down there," she said. "It was hard because nothing in New Orleans told me how many calories I was consuming."