In spite of new evidence that Americans are eating themselves to death — and killing the economy, too — there’s a dispute in Congress over how to get them to quit.

[IMGCAP(1)]The issue is: How much of a break on insurance premiums should employees get for participating in corporate wellness programs?

Most big corporations and some smaller ones now encourage their employees to get health screenings, exercise regularly, improve their diets, quit smoking, and keep their cholesterol and blood pressure under control.

Some of the programs — like Safeway’s and Johnson and Johnson’s — have shown dramatic results and 70 to 80 percent participation rates. The problem is that only 20 to 40 percent of employees participate at most companies.

Right now, federal regulations allow companies to reduce insurance premiums by 20 percent to encourage participation in such programs.

The Senate’s version of health care reform includes an amendment sponsored by Sens. Tom Harkin (D-Iowa) and Mike Enzi (R-Wyo.) to raise the limit to 30 percent, study the effects and, possibly, let the government permit a 50 percent break.

The measure has the support of corporate groups, insurance companies, disease management firms and the Partnership to Fight Chronic Diseases, which includes various disease advocacy groups.

But, surprisingly — actually, shockingly, to me — many of those same groups, including the American Cancer Society, the American Heart Association and the American Diabetes Association, are against the measure on the grounds it discriminates against people who want to stay fat and won’t quit smoking.

In June, 50 groups including unions and AARP wrote Members of Congress saying they are all for workplace wellness programs, but “we are very concerned that individuals not be penalized … if they are sick or presently engage in specific behaviors or have certain conditions, such as smoking or obesity.—

The groups succeeded in keeping the Harkin-Enzi language out of the House’s health care reform bill and likely will lobby the administration to keep it out of a House-Senate conference agreement.

The question has to be asked: Are these people serious about fighting chronic disease or not?

According to studies reviewed by the pro-Harkin group, Health Promotion Advocates, about 40 percent of all U.S. deaths — 900,000 a year — result from unhealthy lifestyle choices such as tobacco use, obesity, lack of exercise or misuse of drugs and alcohol.

Unhealthy lifestyles are the primary contributor to the six leading causes of death — and health expenditure — in the United States, including heart disease, cancer, stroke, respiratory diseases, accidents and diabetes.

Chronic conditions account for an estimated 75 percent of the nation’s $2 trillion annual medical expenses, and two-thirds of the increase in health care spending can be attributed to unhealthy behaviors, especially obesity.

On that score, a new study by Emory University health expert Ken Thorpe showed that incidence of obesity has risen from 12 percent of the U.S. adult population in 1989 to at least 27 percent in 2008 and, at the present rate of overeating, will rise to 43 percent in 2018, or perhaps even 48 percent.

If current trends continue, he found, obesity-related spending will quadruple to $344 billion in nine years, though if the obesity rate could be held to present levels, the United States could save $200 billion a year in health costs — enough to pay a quarter of the cost of health reform.

Obesity, Thorpe said, “is the fastest-growing public health challenge the nation has ever faced.—

According to the American Heart Association, 72 percent of white men and 58 percent of white women in America are overweight, along with 74 percent of African-American men and 77 percent of women, and 75 percent of Hispanic men and 73 percent of women.

The AHA estimates that 32 percent of both white men and women are obese, 37 percent of black men and 53 percent of black women, and 27 percent of Hispanic men and 42 percent of Hispanic women.

(“Overweight— is defined as having a body mass index over 25 — 170 pounds for an adult 5 feet 9 inches tall. “Obese— is a BMI over 30, or 200 pounds.)

At the AHA’s annual meeting this summer, scholars said that the increase in overweightness and obesity among children and teens, from 20 percent in the mid-1980s to 35 percent now, threatens to wipe out medical gains made in combating heart disease.

And yet, the AHA is among the groups opposing the Harkin-Enzi measure. The group did not respond to an inquiry, but a spokesman from the American Cancer Society did.

He said that the group is not opposed to the current 20 percent insurance break but is opposed to raising it to 30 percent or 40 percent because premium reductions for wellness participants will result in premium increases for non-participants.

The ACS, AHA and American Diabetes Association issued a statement last week declaring that “such a plan would shift substantial costs onto the backs of the least healthy workers and open a large back door to discrimination against people with chronic diseases.—

However, the Harkin-Enzi measure specifically allows employees with chronic illnesses to get a doctor’s certification that they are unable to participate in wellness programs and still get a premium discount.

According to Michael O’Donnell, editor of the American Journal of Health Promotion, corporate wellness programs show significant results in encouraging smoking cessation and blood sugar control, but less in controlling obesity.

Clearly, obese people — who are killing themselves and causing huge increases in health spending, including higher premiums for their co-workers — need better incentives to lose weight.

These ought to include significant breaks in insurance premiums. I’d even favor higher rates for those who will not lose weight and lack a legitimate medical reason why.

The nation produced dramatic reductions in smoking by banning it in public places. We can’t force fat people to eat outside, but we ought to offer them every incentive to lose weight, and penalties if they don’t.

The question is: How serious are we about fighting preventable chronic disease, which is driving the country broke?