Steam cooking is a healthy cooking method. Since food is cooked by direct contact between steam (conduction) as well as the movement of the hot vapor through the food (convection), no oil is needed to conduct the heat. 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 more nutrients.