US fast-food giant McDonald's unveiled a revamped menu Tuesday in a move to offer healthier options and join the fight against obesity, drawing praise from First Lady Michelle Obama.

The chain will add a serving of fruit or vegetable to its "Happy Meals," which are aimed at children, and shrink the portion of .

The new French fry holders will contain 1.1 ounces (31 grams) of potatoes, down from 2.4 ounces. The meals also will include apple slices, carrots, raisins, pineapple slices or other fresh produce. The change will cut calories by an average of 20 percent.

The move comes amid pressure from health advocacy groups to get the fast-food industry, blamed for much of the , to offer more healthy choices.

"McDonald's is making continued progress today by providing more fruit and reducing the calories in its Happy Meals," the first lady said in a statement.

"I've always said that everyone has a role to play in making America healthier, and these are positive steps toward the goal of solving the problem of . McDonald's has continued to evolve its menu, and I look forward to hearing about the progress of today's commitments, as well as efforts in the years to come."

McDonald's will begin rolling out the new in September, with the goal of having them available in all 14,000 restaurants in early 2012.

The new Happy Meal will also include the choice of a hamburger, cheeseburger or Chicken McNuggets, and options for low-fat milk.