Chicago ? McDonald’s plans to use a new cooking oil for french fries and other fried foods that it says will do less damage to your diet.

Nutritionists call the fast food giant’s effort to reduce trans fatty acids a good first step but say the change doesn’t make french fries a health food.

“They’re still french fries, and they’re still high in fat,” said Kathleen Zelman, a registered dietitian and spokeswoman for the American Dietetic Assn. “But if people are going to eat them anyway, we can at least reduce the saturates which are artery-clogging.”

The Oak Brook-based company says the new oil, which will be used to cook all of its fried foods, will halve the trans fatty acid levels in its french fries while increasing the amount of the more beneficial polyunsaturated fat.

Trans fatty acids increase the body’s levels of bad cholesterol while simultaneously reducing its levels of good cholesterol, said Dr. Meir Stampfer, professor of epidemiology and nutrition at Harvard School of Public Health.

“People don’t have to change their habits, they don’t have to exert willpower; without doing anything they would be eating a healthier diet,” he said.

McDonald’s worked with its longtime supplier Cargill to develop the new oil, which a few restaurants will begin using in October. All 13,000 domestic restaurants will use the oil by February.

Phil Sokolof, president of the National Heart Savers Assn., said McDonald’s announcement would give consumers a false sense of security when eating fast food.

“French fries are still one of the worst foods for raising cholesterol level,” Sokolof said.