Obesity is now a global health issue. According to the World Health Organization, the top 10 leading risk factors for death in 2000 included four directly connected to obesity—hypertension, cholesterol, high body mass index and physical inactivity.

To tackle the problem, the WHO is launching a worldwide campaign against obesity. Its chief tool is a strategy to promote changes in diet and nutrition similar to what the U.S. Department of Agriculture has recommended for many years.

Shiriki Kumanyika, the vice-chair of the WHO panel that drafted the guidelines and strategy and a Penn obesity researcher, now finds herself in the middle of a global food fight, facing opposition to the campaign from the food industry and, in an ironic twist, the U.S. government, whose own dietary guidelines closely mirror those being endorsed by the WHO.

A professor of epidemiological biostatistics and epidemiology and associate dean for health promotion and disease prevention in the School of Medicine, Kumanyika is used to doing work on politically sensitive subjects—her area of research interest is obesity among black women—but being thrust into the public eye comes as a surprise. She now finds herself fielding calls from the media and traveling to developing countries to explain and defend her group’s recommendations.

The fight, she told a Medical School seminar Feb. 12, is reminiscent of the campaign the tobacco industry waged for decades against research showing strong links between smoking and respiratory disease. And it’s being waged for the same reason: Powerful business interests—and, in this case, some developing countries—would take a big financial hit if the strategy was implemented as planned. “Food trade is a major portion of global trade,” she said.

Because it is impossible to prove beyond doubt that a given risk factor causes a particular condition, critics with vested interests often claim that policies harming those interests are based on “junk science,” or that “no clear evidence exists” to link a risk factor to a disease. The “G-77” group of developing nations—many of which grow sugar, one of the foods whose intake should be limited according to the guidelines—used the latter argument in announcing their opposition to the strategy.

Kumanyika pointed out in the seminar that researchers have found convincing evidence—the highest standard in the field—that the amount and frequency of free sugar consumption greatly increases the risk of dental disease, particularly cavities.

The chief U.S. objections are to the parts of the strategy that call for changes in the way the public gets information about food and nutrition, including marketing. The Department of Health and Human Services succeeded in getting language inserted into the draft WHO strategy that places increased emphasis on personal responsibility.

Kumanyika noted, however, that this approach has already failed in the United States. “The ‘Healthy Children 2010’ initiative sought to reduce childhood obesity from 10 percent in the early 1990s to 5 percent today. Instead, it’s gone up to 16 percent, so it’s clear that whatever we’re doing is not working,” she said.