More than 10,000 people around the region will take a fitness-inducing midday stroll Wednesday to mark National Walk @ Lunch Day. Half of them will be walking laps around Rittenhouse Square.

Will it make much of a difference?

Not if the walkers are looking to lose weight fast. An average person walking at an average pace for 30 minutes a day, five days a week, would need about seven weeks to expend the 3,500 calories that equals one pound.

But there is a bigger point, said Gary D. Foster, director of Temple University's Center for Obesity Research and Education, who reluctantly did the math because there is a broader message in this: "Walking is a fantastic thing to do. Because it improves your health. And it is the single best predictor of who keeps weight off and who doesn't."

The national Blue Cross and Blue Shield Association started Walk @ Lunch Day five years ago. Most affiliates, such as Horizon Blue Cross Blue Shield of New Jersey, involve only their own workers.

But Independence Blue Cross has recruited more than 100 of its subscriber organizations in Southeastern Pennsylvania. Last year, it had the biggest turnout in the nation.

At most companies, participants will walk around their own campuses. Those in Center City will walk around Rittenhouse Square, while hearing speeches from Mayor Nutter and other luminaries. (Three times around, plus going to and from the office, equals roughly one mile.)

"We are using this as a way to jump-start the adoption of wellness programs and, in particular, walking-related wellness programs," said chief medical officer Richard Snyder. The overarching goal "is to emphasize to employees in the workplace that you can get exercise in the normal course of your day," he said.

Even modest physical activity, he noted, leads to "improved mood, decreased stress and even better sleeping habits."

Snyder said the insurer was analyzing preliminary data from walking-based wellness programs it ran with companies last year. The results appear to show improvement on cardiovascular health measures such as cholesterol, blood pressure, and waist-to-hip ratio.

Last year's programs included education, social media, and "very modest incentive programs," he said. "Sustainability is an issue. It is easy to get started."

Independence Blue Cross has a publicly accessible website,, with tips, maps, and a GPS-enabled app to track walks and record and share calories burned.

The National Business Group on Health, a nonprofit that represents large employers, cites research estimating that medical costs for obese patients are one-third higher than for normal weight people. Obese workers typically have higher levels of type 2 diabetes, hypertension, heart disease and lower back pain, all of which causes more absenteeism. The group recommends broad-based wellness programs that combine healthy food and physical activity.

Walking was a key focus of wellness programs that Denice Ferko-Adams developed as a consultant for dozens of organizations over 15 years before becoming director of the new MacDonald Center for Obesity, Prevention and Education at Villanova University last year.

"I promote walking for several reasons," she said. "One, it's easy: most everyone can walk. Two, it's inexpensive: you only need a good pair of walking shoes. Three, it's accessible: You can do it anywhere. Four, if the weather is bad, head to a mall to walk indoors or to buy the right clothing [layers] to exercise outside year-round. Five, it is sustainable: Once you get into the habit, you will begin to feel the other benefits of exercise."

Ferko-Adams favors programs that measure time (30 minutes) rather than distance (one mile) because they level the playing field, especially for the couch potatoes who have the most to gain.

She advocates working with employees on an individualized approach: One person may need to pay to take a class in order to feel compelled to continue, while simply taking up biking may do it for another.

When 20 percent or 30 percent of a company participates, said Ferko-Adams, the culture begins to change. People talk about what food is being served at a meeting, for example.

Ultimately, there is no free lunch.

"The number one way to improve heart disease and diabetes is eating and lifestyle changes," Ferko-Adams said. "But most people will go for the quick fix: medication. They [think they] can eat the doughnut because they are taking the Lipitor."

It doesn't work.