CHICAGO (AP) _ McDonald's plans to introduce a new, all white-meat Chicken McNugget with less fat and fewer calories, the latest move by the fast-food giant to offer healthier fare.

In the next six weeks, McDonald's will begin offering the smaller McNuggets in all of its 13,600 U.S restaurants, the Chicago Tribune reported in Sunday's edition.

The revamped McNuggets are designed to meet a growing consumer preference for chicken breast meat. The change is a big, and some say risky, move for the Oak Brook-based company.

Ever since McDonald's first unveiled McNuggets in 1983, they have been one of the restaurant's most popular entrees, especially among children.

But the company says extensive consumer tests over the past six months show the time is right to shift from a McNugget that is 30 percent dark meat to one that's 100 percent white meat.

``It's clear now that consumers prefer white meat, so we started to work on how we might evolve the McNugget to a situation where it is now all white meat,'' said Wendy Cook, McDonald's vice president of menu innovation.

In September, the hamburger chain unveiled it was test marketing an adult version of its Happy Meal. Rather than a burger and a toy, the new Go Active meal will include a salad, an exercise booklet and a pedometer meant to encourage walking.

The new six-piece McNuggets will contain 260 calories, down from 310 calories, and 16 total grams of fat, down from 20 grams.

William Mikel, a University of Kentucky professor and specialist in meat processing and product development, wonders if consumers will reject the new McNuggets the way they rejected Coca Cola's New Coke in the mid-1980s.

``I think they probably have a good idea, but we as consumers, we're a fickle bunch,'' he said.