Wendy's International Inc. (WEN) said Thursday it will begin frying french fries and breaded chicken items with non-hydrogenated oil, continuing a shift to offer healthier menu choices.

The country's third-largest burger chain said the blend of corn and soy oil has zero grams of artery-clogging trans fat per serving and will cut trans fat in those menu items by 95 percent. Wendy's will begin using the oil in its 6,300 restaurants in the U.S. and Canada in August.

"The trend is for a bit healthier," said Lori Estrada, Wendy's senior vice president for research and development. "We wanted to look at our products and improve our nutritional profile."

Trans fat raises bad cholesterol and lowers good cholesterol. Eating just 5 grams a day raises the risk of heart disease by 25 percent, research shows.

The new oil will reduce trans fat to zero grams for Wendy's chicken sandwiches, chicken nuggets and chicken strips. A large order of french fries will go from 7 grams to 0.5 grams while an order of fries from the kids' menu will have zero grams.

Wendy's, based in the Columbus suburb of Dublin, said it is working to further reduce trans fat in fries that occurs when suppliers partially cook the potatoes before shipping them to restaurants.

Fries and sandwiches cooked in the new oil taste and cost the same, Estrada said. Wendy's also has to train workers on how to use the new oil, which has a shorter shelf life than the old one.

Wendy's has been working on the new oil for two years and testing it for a year at 370 restaurants in Florida, North Carolina, West Virginia, and Ontario.

McDonald's Corp. (MCD) pledged four years ago to switch to an oil that would cut in half the level of trans fats in the top-selling chain's fries. However, Chief Executive Jim Skinner said in April that the Oak Brook, Ill.-based company was still testing the oil and did not know when they would make the change.

Earlier this year, Wendy's cut all trans fat from salad dressings and last year the chain started offering margarine with zero grams of fat per serving for baked potatoes.

In 2004, it began offering combo meal choices that allowed customers to pick chili, a baked potato or a side salad instead of fries, and offering milk and fruit for substitution in kids' meals.