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."