Whether either one succeeds in helping to improve eating habits that are linked to chronic diseases - or merely clutters up menus - will likely be debated for years.
Are consumers shocked upon discovering that, say, Applebee's Teriyaki Shrimp Pasta, listed in the "Unbelievably Great Tasting & Under 550 Calories" section, contains 3,410 milligrams of sodium - more than double the recommendations for most adults? (More to the point: Do they change their order?)
Are restaurants so embarrassed by the contents of their food that they reformulate the most extreme items?
Could a lot of little changes - a slight impact from labels, a little more exercise and less soda, a better background in nutrition from school - eventually shift the national eating pattern from just above to just below the max?
"There is no silver bullet," said Rogan Kersh, a professor of public policy at New York University. Kersh, who is studying the impact of labeling here and elsewhere, compared food-related prevention strategy to how doctors treat a patient with complex health issues: "We wouldn't try one thing and see if it works."
The idea of placing nutritional information right next to price and description on menus - visible at the "point of purchase" - has been around for only a few years. Initially the restaurant industry bitterly opposed the move, and unsuccessfully sued to stop the first mandate, in New York City, which began in mid-2008.
As local variations of the concept began popping up around the country, however, restaurants decided to seek uniform national guidelines. Those became part of the federal health-care overhaul, which was signed by President Obama on March 23, 2010 - and gave the Food and Drug Administration one year to write the regulations.
Dozens of local and state proposals that were in process around the country, including New Jersey, were put on hold. Even in Philadelphia, which reports 83 percent compliance, the city has so far refrained from issuing tickets for fear that challenges could be tied up for years in court.
Meanwhile, researchers seeking to tease out the most effective strategies were left to study the handful of places whose rules had been at least partially implemented.
Very early findings from NYU indicate that Philadelphians noticed calorie information in restaurants twice as often after labeling went into effect as before; a control sample in Baltimore experienced no change. In an unrelated survey by the Public Health Management Corp. (PHMC), 38 percent of people who had eaten at a Philadelphia restaurant with posted information in the previous month said they ordered a lower-calorie food as a result; 4 percent said they chose a higher-calorie option; and 58 percent said they were not influenced by the posting.
Those findings alone mean little, however, since some studies elsewhere have shown that people think they are eating healthier in response to the labels while actual receipts prove otherwise - one example of why human behavior is difficult to study in the real world.
Perhaps the most comprehensive study examined more than 100 million transactions at all 316 Starbucks in New York, Boston, and Philadelphia during the three months before and 11 months after the Big Apple required labeling on menu boards (Philadelphia had not started yet).
The analysis, by the Stanford Graduate School of Business, found an average 6 percent reduction in calories per transaction as a result of the labels, with most of the 14-calorie difference coming from food. Consumers who averaged more than 250 calories per transaction cut back by 26 percent. Store revenues were unaffected.
Of course, Starbucks caters to an educated clientele. Doctors and nutritionists might be expected to pay more attention as well.
"I've stopped eating at certain places that haven't posted it," Health Commissioner Donald F. Schwarz said Tuesday. "I'm particularly attentive to sodium in restaurants . . . given how many people we have with hypertension and kidney disease."
Nearly 36 percent of Philadelphia residents (44 percent of African Americans) said they had been diagnosed with high blood pressure, according to PHMC's 2010 Household Health Survey. Federal guidelines recommend less than 2,300 milligrams of sodium a day but 1,500 for African Americans, people age 51 or over, and anyone with hypertension, diabetes, or chronic kidney disease - half the population.
Philadelphia's labeling ordinance is considered the strictest in the country because it requires chain restaurants - all the laws apply only to chains, which serve standard menus and can more easily afford to analyze nutritional content - to list not only calorie counts but also saturated fat, trans fat, carbohydrates, and sodium next to every item on printed menus in sit-down establishments. Menu boards found at fast-food establishments and food tags common in display cases must list only calories.
The federal law, like most others, requires only calories everywhere, although it includes vending machines, which few others do. It will supersede all local laws, although waivers may be granted in some cases. Philadelphia intends to apply for a waiver but cannot do so until the regulations are set.
The city determined that 726 establishments owned by 112 chains are covered by its ordinance. Most of the more than a dozen that were asked about the impact declined to comment.
John M. Scardapane, chief executive officer of Conshohocken-based Saladworks, said that measuring nutritional content was difficult - four methods each came up with different numbers - and cost "six figures."
Customer response for the health-oriented chain was "absolutely nothing" said Vince Rosetti, who owns franchises in Northeast Philadelphia and in Bensalem - although he said the company did remove perhaps its least healthful item, chicken-pot-pie soup, just before the labels went up and replaced it later with a reformulated recipe.
Labels can be confusing, too. Some places include the condiments; others give them separately. Calories listed as ranges for a single item are common, as in McDonald's "fountain drinks: 0-350."
"I still think the biggest problem is aesthetics," said George McKerrow Jr., president and CEO of Ted's Montana Grill, whose numbers-packed South Broad Street menu hints of a spreadsheet. He said the main ordering change seemed to be a slight shift from bigger desserts in favor of small cookies.
Some research suggests that giving people a context for their calculations makes a difference. Philadelphia, for example, requires printed menus to include a statement that typical dietary needs total 2,000 calories a day.
Nutritionists, policymakers and restaurateurs do seem to agree on one point: No tactic will do much by itself.
On Monday afternoon, Cynthia Mabrey, 50, carefully wrapped and tossed an uneaten half-bagel from Dunkin' Donuts (245 calories, including half a packet of cream cheese).
Mabrey, a registered nurse at Mercy Hospital of Philadelphia, has paid close attention to the labels for a year and added Weight Watchers five months ago. The family goes to the YMCA together. They eat out together.
"I have them look at the menu. And if they pick something like a Big Mac, I have them look again at the calories, the sodium, the fat," she said.
She said she had lost 25 pounds, and her 17-year-old daughter lost 50 in a year and a half.
"My doctor tells me if I lose weight and make the right food choices, I won't have to be on medication," Mabrey said. "The labeling helps."
Contact staff writer Don Sapatkin at 215-854-2617 or email@example.com.