The Golden Arches said on Tuesday that it would phase out the jumbo servings as it moves to a healthier menu "with a range of choices that support a balanced lifestyle".

Sixty percent of American adults are either overweight or obese, and $75 billion is spent in obesity-related health costs every year.

Pundits have laid much of the blame for the growing medical crisis on the nation's fast-food, couch potato culture.

High calorie meals

They have pointed out that a "super sized" serving of fries comes with 610 calories, versus 200 calories for an average order of McDonald's French fries in 1960.

However, McDonald's has already done much to overhaul its offerings.

It has introduced salads, changed the 20-year-old recipe for its Chicken McNuggets to cut calories and fat, and traded the oil it cooks its fries in for one lower in saturated fats.

Most American adults are obese
or overweight

The burger chain has worked with nutritionists to educate customers who are watching their calorie, fat or carbohydrate intake about what menu items they can eat.

Healthy eating

It is also planning to roll out a healthy adult version of its children's Happy Meal. The offering will come with water, a salad and exercise book produced by Oprah Winfrey's trainer, Bob Greene.

McDonald's said the switch to more healthy options is designed to appeal to increasingly calorie and health-conscious consumers, and to promote a "new national debate" about nutrition and fitness.

But McDonald's and other food chains have found themselves in the hot seat as study after study spells out the scope and consequences of the nation's obesity epidemic.