Seattle ? Starbucks Corp. is cutting trans fats from the doughnuts, muffins and other treats in half of its U.S. stores, and plans to eventually drop the artery-clogging fats from company-operated coffeehouses across the country.

The world’s largest specialty coffee retailer has been working to eliminate trans fats from its food menu for about two years, spokesman Brandon Borrman said Tuesday.

Trans fats, listed on food labels as partially hydrogenated vegetable oil, are believed to be harmful because they wreak havoc on cholesterol levels.

Standalone Starbucks stores in Seattle, San Francisco, Chicago, Los Angeles, San Diego, Boston, New York, Philadelphia, Washington, D.C., and Portland, Ore. will have zero trans fats in their food as of Wednesday, Borrman said.

Getting the other half of U.S. stores to follow suit will take some time, as the company adjusts recipes with regional bakers and food suppliers.