Answer:
Steaming: Locks in nutrients that would be lost if the same item was boiled in water. Some vitamins are water soluble and sensitive to heat and air.
Frying: Using non-stick pans can drastically reduce the use of oils and fats. Use mono/polyunsaturated oils sparingly or use spray oils.
Baking/roasting: Silicone bakeware and draining on paper reduces the amount of oil eventually consumed.
Meat: Choose meats trimmed of visible fat.
Microwaving: May be suitable for heating single items that will be served straightaway.