Tomecia Weaver still winces when she recalls being passed over for a sales rep job at a pharmaceutical company early in her career.

She was one of two finalists: Her competitor had a weaker academic record and no background in sales. "They told me I didn't have enough sales experience," said Weaver. But someone involved in the selection process later confided she had been deemed too heavy for the job.

"That hurt," said Weaver, now a diversity specialist at American Express Financial Advisors in Minneapolis.

When it comes to girth in the workplace, there is plenty of pain to go around. With 64 percent of American adults now overweight or obese, businesses are shouldering billions of dollars in weight-related medical claims and lost productivity.

At the same time, some heavier workers say they're tired of insensitivity and discrimination on the job. As feelings about fitness and fairness collide at work, "size-ism" is emerging as the latest diversity frontier.

Recent medical research has grim implications for employers. Obesity is a greater trigger for chronic illness than smoking, alcoholism or poverty, according to a 2002 study by the RAND Corp., a think tank in Santa Monica, Calif. As a result, health-care costs are higher for obese people than for any other group studied, except the elderly.

The price tag for American businesses is heavy — $12.7 billion a year, according to the Washington Business Group on Health, a national nonprofit organization.

Given current trends, that cost is expected to continue climbing: This week RAND reported that the ranks of the severely obese quadrupled between 1986 and 2000.

Meanwhile, in today's competitive job market, bias against overweight people is commonplace, obesity-rights advocates say. The overweight are slighted in the areas of hiring, promotion, compensation and layoffs, according to Mark Roehling, an assistant professor at Michigan State University, who reviewed 49 studies on the subject.

Roehling has interviewed dozens of heavy people about their job-hunting experiences. One woman told him that she sat at a job interview and watched in horror as her interviewer wrote in big letters across the top of her resume: "TOO FAT."

Discrimination is especially acute in workplaces where a premium is placed on personal appearance, such as executive-level positions, sales, public relations and other areas where client contact is key, said Mary Story, a University of Minnesota professor who studies obesity.

In a 1990 study of several hundred people by University of Vermont professor Esther Rothblum, the heaviest were most likely to report they had been denied benefits including health insurance because of their size. Many said they had been fired or threatened with dismissal for weight reasons.