NEW YORK >> An apple a day may keep the doctor away. But when you put it in a Happy Meal, it might help keep regulators at bay too.

McDonald’s on Tuesday said that it would add apple slices and reduce the portion of French fries in its children’s meal boxes this fall, effectively taking away consumers’ current choice between either having apples with caramel dip or fries as a Happy Meal side. McDonald’s also said it is offering a new mobile app focused on the nutrition of its fare, and is reducing sugars, saturated fats and calories in its main menu items.

The moves by McDonald’s Corp., which has become a leader among its peers in offering nutritious choices like oatmeal and salads, comes as fast food chains face intense scrutiny from health officials and others who blame the industry for childhood obesity and other health-related problems. Some municipalities, including San Francisco, have even banned fast food restaurants from selling kids’ meals with toys.

Critics wasted no time complaining that the changes don’t go far enough. Kelle Louaillier, executive director of a group called Corporate Accountability International, said McDonald’s is just trying to get ahead of impending regulations that will restrict the marketing of junk food to children and require restaurants to post nutrition information on menus, among other changes.

"McDonald’s is taking steps in the right direction, but we should be careful in heaping praise on corporations for simply reducing the scope of the problem they continue to create," said Kelle Louaillier, executive director of a group called Corporate Accountability International.

Cindy Goody, McDonald’s senior director of nutrition, said the new directives are "absolutely not" related to new regulations, but rather a response to the fact that customers want healthier choices but weren’t picking them. Indeed, only about 11 percent of customers were ordering apples with their Happy Meals, even though 88 percent were aware of they had the option of having fries or apples, the restaurant said.

McDonald’s says the change will reduce calories in its "most popular" Happy Meals by as much as 20 percent. Currently, the lightest Happy Meal is the four-piece chicken nugget served with apples and apple juice. It has 380 calories and 12 grams of fat. The Happy Meal with the most fat and calories is a cheeseburger served with fries and 1 percent chocolate milk. It weighs in at 700 calories and 27 grams of fat.

"McDonald’s agrees with leading food and nutrition experts that making incremental lifestyle modifications with food consumption may lead to improvements in an individual’s well-being," Goody said, adding that McDonald’s didn’t eliminate fries from Happy Meals because "all foods fit when consumed in moderation."

Adding a half portion of apples and fries is more likely to change customers’ eating habits than simply offering apples as an alternative, said Jonathan Marek, a senior vice president at Applied Predictive Technologies. It could drive sales, he said.

"The key is, will this get parents to go to McDonald’s one more time each month than they would have otherwise?" said Marek, whose company helps restaurants forecast whether new programs will drive sales. He was not involved in the McDonald’s program.

This isn’t the first time the world’s largest burger chain has tried to paint itself as an emissary of nutrition.

In the ’80s, it created a fitness program for middle school children featuring gymnast Mary Lou Retton. A decade ago, McDonald’s used its mascot, Ronald McDonald, to encourage parents to get their children immunized and to tell kids to drink milk. In 2003, it added salad entrees to the menu. And in 2004, McDonald’s christened Ronald a "balanced, active lifestyles ambassador."

More recently, McDonald’s has worked to paint itself as a healthy, hip place to eat, offering wireless access in restaurants and introducing smoothies, salads, yogurt parfait and oatmeal. Other fast-food companies are now scrambling to replicate McDonald’s offerings.

"We’ve been in the nutrition game for over 30 years in providing nutrition information to our customers," said Goody, the McDonald’s spokeswoman. "Now what we’re doing is we’re adding more food groups and … creating nutritional awareness."

In part because of its ability to change with consumer tastes, McDonald’s has posted robust financial results during the recession in and its aftermath.

In 2010, McDonald’s accounted for 9 percent of U.S. restaurant sales, according to Technomic. Last year, its U.S. revenue rose 4.4 percent, while U.S. revenue fell at Burger King, Wendy’s, Kentucky Fried Chicken, Arby’s, Sonic and Jack in the Box, Technomic said.

McDonald’s ability to adjust to customers’ demands has helped bring already-loyal customers through the doors more often, but they’re also attracting "people who hadn’t traditionally visited us in the past," said McDonald’s spokeswoman Danya Proud.