Two years after New York City declared war on artificial trans fats, nearly all city restaurants had successfully cut the artery-clogging fats from their menus, health officials reported Monday.

In December 2006, the city’s Board of Health decided to launch a gradual trans-fat phase-out from all licensed eating establishments - including restaurants, school cafeterias and street vending spots.

By November 2008, more than 98 percent of city restaurants had stopped using artificial trans fats for cooking, frying and baking, researchers with the city’s health department report in the Annals of Internal Medicine.

Trans fats have become notorious because they not only raise so-called “bad” LDL cholesterol, as the saturated fats in animal products do, but also lower levels of so-called “good” HDL cholesterol.

While some meats and dairy products naturally contain trans fat, most trans fats in people’s diet are artificial; they are formed when manufacturers add hydrogen to vegetable oil to make it solidify.

These so-called partially hydrogenated oils were long a staple in processed foods, like crackers, cookies and pastries, and widely used by restaurants in cooking, frying and baking.

In 2006, before the health department ban, half of New York City’s restaurants were using trans fats. By November 2008, less than 2 percent were, according to Dr. Sonia Y. Angell and her colleagues at the Department of Health.

When the restriction was first adopted, the researchers note, some critics claimed it was an Orwellian measure, while others worried that restaurants would have a tough time finding suitable trans-fat replacements.

However, the transition has been smooth, Angell’s team writes, asserting that trans-fat restriction “is now a largely unnoticed part of New York City life.”

The researchers point out that food manufacturers have been quick to market trans-fat-free shortenings and other products, making the transition easier for restaurants. In general, they say, city restaurants report that the change has been “cost neutral.”

Since New York’s measure passed, more than a dozen jurisdictions, including California, have adopted similar laws, and many national restaurant chains have cut trans fats from their menus, Angell’s team notes.

Ridding the food supply of trans fats, the researchers write, could potentially improve the cholesterol levels of millions of people.

SOURCE: Annals of Internal Medicine, July 21, 2009.