Well, it depends on your definition of "healthy" since I'm of the opinion that nothing that has aspartame is healthier than something with all-natural ingredients, even if the thing with the natural ingredients is full of natural fats and natural sugars.

That is pretty much true here, too-- a lot of fat-free things are either flavorless or kind of disgustingly sweet. A year or two ago I tasted some low calorie yogurts that pretty much tasted like kitty litter with sugar in it. It was vile.