McDonald's Happy Meal kids meals in both Canada and the U.S. are changing -- but in different ways.

McDonald's Canada says it will be testing a new Happy Meal in the fall that will include a small serving of 1 per cent milk fat yogurt. The yogurt will come in addition to the drink and entree already offered. There will still also be the choice of fries or apple slices.

McDonald's Canada spokesperson Karin Campbell tells CTV.ca that the size of the fries offered in the Happy Meals will be reduced to 31 grams, from the current 71 grams, and will contain about 100 calories.

She was not able to say how many calories would be in the new yogurts, but said all Happy Meals will add up to fewer than 500 calories.

In the U.S., meanwhile, McDonald's plans to add apple slices to all Happy Meals. The company announced Tuesday that by the beginning of next year, Happy Meals in the U.S. will include a half-order of apples and a half-order of fries. Customers can get all fries or all apples if they ask.

Toys will still be included and the price of the meals will not change with these adjustments.

Registered nutritionist Theresa Albert called the changes "necessary," saying they add some protein and calcium to the meal.

But parents can still make a Happy Meal even healthier for their children by choosing milk or water instead of pop, saving another 100 calories.

"You've got to bend once in a while and say ‘yes' to these kinds of things, and just make wise choices when you're there," Albert told CTV News Channel.

"These are treats. This is not living on food, this is treat food."

Campbell explained that the options in the U.S. and Canadian Happy Meals are different because each company responds to what its customers want and ask for. She says McDonald's Canada sold nearly 3.5 million pounds of apple slices last year -- an increase of nearly 50 per cent since the apples were first offered in Canada in 2006.

McDonald's USA says the changes to their Happy Meals will cut the number of calories in the meals by 20 per cent. It will also reduce the total fat in the meals, though it wasn't clear by how much.

McDonald's USA also promised Tuesday to reduce sugar, saturated fats and calories in its meals, through "varied portion sizes, reformulations and innovations," by 2020. It didn't give details as to how it would do this.

By 2015, the restaurant chain also plans to reduce sodium by 15 per cent. It said it had already started to do this by reducing the sodium levels in most of its chicken items.

"The commitments we're announcing today will guide the future evolution of our menu and marketing," Jan Fields, president of McDonald's USA, said in a news release.