BANGOR – Dwight Knightly, 5, dipped his Wendy’s french fry into catchup before placing it into his mouth and munching it down.

The child described the fried potato as “good.”

His mother, Leah Knightly of Bangor, was surprised to learn the fry her son was eating was made with Wendy’s new healthier oil, a non-hydrogenated cooking oil that contains minimal amounts of artery-clogging trans fats.

Wendy’s International Inc., the third-largest hamburger chain in the United States, switched in August from a vegetable blend oil at all of its 6,300-plus restaurants in the United States and Canada to a soybean and corn oil that doesn’t contain any of the trans fats that increase the risk of heart disease.

The move cuts trans fat in fried menu items by 95 percent, the company’s Web site states.

Local Wendy’s restaurants made the change several weeks ago, Ann White, co-manager of the Union Street restaurant, said recently. The fast food restaurant is one of 15 operated in Maine by Rest Wend Inc., which also operates the Wendy’s by the Bangor Mall and the one in Orono.

“[Customers] didn’t seem to notice at all,” White said. “I never had anyone come up and say anything. As far as flavor, it does great. And we know it’s a lot healthier for us.”

Anything that is deep-fried is fried in the new oil, she said.

There are 22 Wendy’s in Maine, according to Wendy’s corporate headquarters in Dublin, Ohio.

Breaded chicken nuggets, strips and sandwiches now have zero trans fat, compared with between 1.5 grams to 3 grams before the switch, and the amount in french fries dropped significantly from as much as 7 grams, for a large fry, to between zero and 0.5 grams, she said.

Wendy’s is the first major fast food chain to make the change to a non-hydrogenated oil. McDonald’s is known to be working on a reduced trans fat oil, but has not been able to reproduce the flavor of its famous fries.