Trans fats
A New York regulation that took effect in 2008 prohibits all restaurants from serving food prepared with partially hydrogenated vegetable oil or dishes that contain more than 0.5 gram of trans fat per serving. (Kathy Willens / Associated Press / July 16, 2012)
New York City's pioneering ban on all but the smallest amounts of trans fats in restaurant food has led to a significant reduction in consumption, a change that should translate into better cardiovascular health in the nation's largest city, according to a new report. It also demonstrates that coffee shops, fast-food joints and other eateries can play a major role in improving the health of the public, the study authors said.

Officials from the New York City Department of Health and Mental Hygiene conducted the study to assess whether the regulation that took effect in 2008 — which prohibits all restaurants from serving food prepared with partially hydrogenated vegetable oil or dishes that contain more than 0.5 gram of trans fat per serving — was making a difference for diners.

Public health officials had zeroed in on trans fats because they pose a uniquely potent health risk. Adding fewer than 4.5 grams of them to a 2,000-calorie daily diet can increase the risk of coronary heart disease by 23%, studies have found.

Researchers fanned out across Manhattan in 2007 and examined the receipts of 6,969 diners as they left fast-food restaurants at lunchtime. (The researchers went to fast-food chains because the nutrition information on the items sold there was readily available.) In 2009, they repeated the exercise with 7,885 receipts. They found that diners consumed 2.4 fewer grams of trans fat per lunch after the ban went into effect, according to their study published in Tuesday's edition of Annals of Internal Medicine.

That decline was offset by only a slight 0.55-gram increase in consumption of saturated fats, which are also associated with elevated cholesterol levels.

"Given that one-third of calories in the United States comes from food prepared away from home, this suggests a remarkable achievement in potential cardiovascular risk reduction through food policy," the authors reported.