The law that went into effect April 1 forces companies and government, the two sources of health insurance in Japan, to measure the body fat of employees between the ages of 40 and 74.

Employers may be required to pay more into the national health care system if the waistlines of employees, their families and retirees exceed the government’s limits of 33.5 inches for men and 35.4 inches for women.

Unlike Japan, employers and government in the U.S. have been leery to punish people into losing weight, preferring instead to use financial incentives to reduce health risks, according to a recent Watson Wyatt survey that said such incentives had increased in recent years. Still, more employers are using strong tactics to outlaw smoking, and a National Business Group on Health survey of employees last year suggested they would support penalties aimed at obese workers.

“We’re not going to hold anybody to any kind of penalties,” says Mary Ann Hauert, director of human resources in North America for Sunstar, a Japanese maker of oral hygiene products.

Employees in Japan who are determined to be overweight can choose to participate in weight-loss programs, but participation may become mandatory if the company faces fines, Hauert says.

Employers in Japan must reduce the number of employees who show symptoms of metabolic syndrome—obesity and high blood pressure, cholesterol and blood glucose. These risk factors can lead to vascular disease and diabetes. Companies must reduce the number of obese employees by 10 percent by 2012 and 25 percent by 2015.

The campaign has even led to the coining of a new Japanese word, “metabo,” to replace the word obese or metabolic. Metabo has quickly come to represent a new national ethos.

“Goodbye, metabolic. Let’s get our checkups together. Go! Go! Go!” say the lyrics of one city’s anti-metabo song, The New York Times reported.

Sunstar, makers of GUM and Butler brand oral hygiene products, have the option of attending what they call Kenko Dojo, described by the company as a “health farm for employees” where workers can attend lectures on dieting, exercise and Zen meditation.

Though Japanese computer maker NEC has said it could face as much as $19 million in fines if its metabo workforce did not lose weight, an NEC spokeswoman in the U.S. writes in an e-mail that the policy in Japan “has nothing to do with and does not reflect the practices of NEC Electronics America. Our employees are the company’s most important assets, and we are committed to a workplace that provides a healthy environment.”