Americans eat way too much. Our diets are laden with dangerous amounts of salt, empty calories from corn syrup and artery-clogging trans fats.
Now the politicians at City Hall want to do something about it. In an effort to curb obesity and improve heart health, city and state public health officials across the country are cracking down on fast food, sugary sodas, trans fats and other unhealthy ingredients. They are banning fast food in certain neighborhoods, demanding that restaurants post calorie counts, and considering taxes on sweetened soda.
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Ever the trend-setter in this arena, New York City announced in January it was leading an initiative to lower salt levels in packaged and restaurant-prepared foods. The move, says health commissioner Dr. Thomas Farley, is based on evidence that most Americans consume too much salt, putting them at higher risk for heart attacks and strokes. Many packaged foods contain sky-high amounts of salt.
It sounds like good public policy. But critics bemoan the lack of evidence showing that this and other initiatives will improve public health and make unhealthy eaters change their ways. Some researchers say the new laws and initiatives represent uncontrolled experiments that could backfire and end up having as many negative consequences as positive ones.
No one has ever conducted large-scale clinical trials to measure the effects of reducing salt intake in the general population, for example. The same is true for bans on trans fats, and few studies have looked at the calorie labeling requirement at restaurants.
In an article published last week in the Journal of the American Medical Association, epidemiologist and Albert Einstein College of Medicine professor Michael H. Alderman argues that lowering salt content in the population may in fact be harmful. He points out that in some clinical trials, reductions in salt levels has led to decreased insulin sensitivity and increased production of a blood pressure-regulating hormone. Alderman has served as a scientific adviser to the pro-industry Salt Institute since 1996.
Farley stands by the city's decision. While the evidence on salt reduction is not yet definitive, he says, most experts are convinced of the potential health benefits. He also says tackling high blood pressure by targeting consumer products is a necessary approach.
"The way that public health has been most successful is when we create environments that make it easy for people to live in a healthy way," says Farley.
That's been the thinking behind the city's many public health interventions of late. In 2006, the city council voted to ban artery-clogging trans fats from restaurants. In 2008, it passed a law requiring chain restaurants to clearly post calorie counts on their menus. Last November, Farley and the state's governor advocated for a tax on sodas to bring in close to a billion dollars annually and discourage consumption of the sugary beverage, which is associated with obesity. The idea hasn't gotten legislative traction yet.
As for the effect of calorie counts on menus, the results have been mixed. A study published in October 2009 in Health Affairs found that some customers actually chose foods with slightly more calories. A recent Stanford Business School analysis, however, found that the menus were associated with a 6% decrease in calorie consumption per transaction for New York City Starbucks (SBUX - news - people) costumers.
The city of New York has been monitoring residents' health through its regular surveys, but has yet to see lower heart disease or obesity rates.
Yale epidemiologist Harlan M. Krumholz, who is in favor of the city's trans fat ban and salt initiative, says it will be at least five years before an effect will be seen from any of these initiatives if they indeed produce one.
In the meantime several cities, including Seattle, Philadelphia and Boston, have followed New York's lead on trans fats and menus with calorie counts. The new salt initiative includes 15 states, numerous major cities and nonprofit health organizations. Only a handful of companies have signed on.
Some cities have tried to strike out on their own. In 2008 the Los Angeles city council banned new fast food restaurants in a poor area of South LA. It's not clear whether the ban had any positive effect. A study published in Health Affairs last fall found that the area actually had a lower density of fast food restaurants in comparison with more affluent parts of LA. The bigger problem might have been that the area has few grocery stores with good produce selections, prompting residents to rely on convenience stores filled with unhealthy packaged foods.
In 2007 San Francisco mayor Gavin Newsom lashed out against high fructose corn syrup and threatened to tax beverages loaded with the stuff. The idea never went anywhere, but it did leave a lasting impression. Last fall a group of parents protested after discovering the chocolate milk served at their children's public school contained the additive. The local manufacturer bowed to the pressure and replaced it with sucrose instead, but the sugar content remained exactly the same.
Dr. Elizabeth Whelan, president of the American Council on Science and Health (ACSH), a consumer education group that gets some industry funding, says New York's policies are misguided. Instead of "harassing" restaurants about salt, she says the city should devote more of its resources to encouraging residents to get their blood pressure checked regularly.
Whelan says it makes much more sense to focus on reducing overall calorie intake than to obsess over fat. She points to an ACSH review of trans fat studies that found removing the substance has no effect on cholesterol and lipid levels. But a similar review published in the Archives of Internal Medicine in 2009 found that trans fat consumption does modestly boost heart disease risk.
Krumholz, the Yale epidemiologist, agrees there is no proof the various New York initiatives will work, but says heart disease rates have become so severe that something needs to change now. "We're doing experiments every day anyway we let (food) manufacturers do it," he says. "This is just public health saying, 'Let's put the brakes on this and try to move it back.'"