WASHINGTON -- Ronald McDonald is urging America's children to get more active.

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Company executives are in Washington, D.C., Tuesday to unveil new Go Active! Happy Meals. The fast-food giant's signature kids menu is being updated to include choices like white or chocolate milk, apple juice and apple slices served with a low-fat caramel dip.

McDonald's President Mike Roberts said customers can substitute those products for french fries and soda that have been part of the Happy Meal for 25 years.

The new options will be available nationwide June 11.

But one nutritionist thinks McDonald's new healthy Happy Meals are going to be a tough sell.

Ruth Williams of St. Jude Children's Research Hospital in Memphis, Tenn., said it's good that McDonald's is offering healthier meals, but she's not convinced a lot of kids will want to eat them.

Williams believes kids might opt out of ice cream for the low-fat caramel dip, but that might be all.

She said the bigger issue is that parents need to instill good eating habits.

The company's new Go Active! campaign is designed to encourage fitness for children and adults.

On May 11, McDonald's launched its national Happy Meal for adults, which includes a salad, a fountain drink of choice or bottled water, a pedometer to track one's daily steps, and an informative booklet. The adult Happy Meals will be available through June 7 or while supplies last.