Next Era’s solution is to use weight as a reward, not a punishment.

“We’re not trying for ideals” in the benchmark, says Miller, the benefits director. For weight, employees get a bonus if their body mass index is under 30 — that’s the threshold for obesity — rather than 24.9, the threshold for normal weight, according to the Centers for Disease Control and Prevention.

Baptist Health South Florida is also using a BMI of 30 as part of its rewards for the same three biometric measures. Chief Human Resources Officer Corey Heller says employees can earn up to $250 annually in incentives, including $50 for not smoking and another $50 for getting a flu shot.

Baptist believes “motivating and incentivizing is the best way to a healthy workforce,” Heller said. “We don’t believe punitive action is necessary.”

Such rewards are spreading across the country. UnitedHealthcare spokeswoman Elizabeth Calzadilla-Fiallo says more than 1.6 million employees have enrolled nationwide in its wellness programs that can lower their premiums by up to $1,000.

Ryder, the Doral-based international logistics company, plans also to offer more incentives in 2013, introducing employees to UnitedHealthcare’s Wellness Portal , where they can earn rewards “by taking healthy actions and engaging with health coaches,” said Pamela Rothstein, Ryder’s benefits director.

Rothstein said Ryder is facing particular challenges because, after five years of lower than average cost increases, it was hit in 2012 by huge increases in claims of more than $100,000. Through the first eight months, such catastrophic claims consumed 27 percent of Ryder’s total healthcare costs, Rothstein said.

Rothstein said Ryder is watching carefully a new concept developed by Aon Hewitt, which has set up a private health exchange, a mirror of what the federal reforms are planning for 2014. While the federal exchange is intended mostly for small businesses and individuals, Aon’s focuses on the large employers that are its clients.

Aon’s Ken Sperling said an employer first decides how much it wants to give each employee for healthcare. That amount becomes a credit that the worker can use to shop on the exchange, where up to nine insurers compete for business by offering four Aon-designed plans.

Workers who choose a plan with fewer benefits may not have to pay anything additional, Sperling said. Those who want more benefits, or lower deductibles, may have to pay more for premiums out of their own pocket.

Aon Hewitt rolled out the exchanges this year, using its own 20,000 employees.

For 2013, Sears Holding and Darden Restaurants, which have more than 100,000 employees are using the Aon exchange.

Calzadilla-Fiallo said UnitedHealthcare is participating in the Aon exchange “to gain valuable insight into consumer behavior,” both for the private exchanges that could grow quickly and for the government-mandated exchanges that will be used by millions in 2014.

Ryder is one of many companies that’s in a “wait-and-see mode,” Rothstein said. “The concept is very new.”

She likens it to a 401(k) in which an employee is given money to manage on his or her own, rather than an employer-defined pension.