Steaming is a very healthy cooking method.
First, since food is cooked by direct contact between steam (conduction) as well as the movement of the hot vapor through the food (convection), no fat is needed to conduct the heat. Often, just few drops of lemon juice is all needed to add to a steamed dish. This makes steaming a lower-calorie, low fat cooking method.
Food stays moist, too, since it is being bathed in water vapor. Also, since water soluble nutrients (namely Vitamins C and B) don’t leach out into vapor, steaming preserves up to 50% more nutrients than other moist heat cooking methods.